Basic Emotions in Clinical Depression During Acute Illness and Inpatient Treatment: Correlations with Change in Emotional Clarity

Abstract

In our longitudinal study, we examined self-reported or explicit basic emotions, i.e., happiness, sadness, anxiety, and anger, in depressed patients during acute illness and inpatient treatment. For exploratory purposes, we also assessed implicit emotions. We analyzed how changes in emotional clarity relate to changes in emotions and depressive symptoms. A sample of depressed inpatients (n = 52) was examined at admission and on average after seven weeks of multimodal psychiatric treatment. A healthy control group (n = 52) was tested at the same time interval. Basic emotions were measured via the Differential Emotions Scale and a discrete-emotions variant of the Implicit Positive and Negative Affect Test. Emotional clarity was measured with the WEFG scales. Patients reported lower explicit happiness and heightened explicit sadness, anxiety, and anger compared to healthy controls, regardless of time of measurement. Across groups and time points, implicit happiness was greater than implicit sadness, anxiety, and anger, with no group differences. Patients’ emotional clarity improved and correlated with improvements in depressive symptoms, explicit happiness, sadness, and implicit anger. In summary, depressed patients experience heightened anxiety and anger, suggesting broader alterations of negative emotions beyond sadness. Increased emotional clarity during treatment was found to be correlated with changes in explicit and implicit affectivity.

1. Introduction

Depression is among the most prevalent and debilitating mental health disorders worldwide, significantly impairing emotional regulation and processing. Individuals diagnosed with depression often struggle to accurately identify and manage their emotional states [1,2], contributing to the persistence and severity of the disorder. Clinical emotion researchers often adopt a categorical approach to exploring emotional dysfunctions and impairments, focusing on basic emotions. Happiness, sadness, anger, fear, and disgust are commonly identified as basic emotions [3,4,5] (see [6] for a review). They are considered universal, innate responses that form the core of human emotional experience [7,8,9]. Basic emotion theory has been very influential, establishing a major theoretical framework for studying emotions [10]. Although it has faced criticism by, among others, proponents of the theory of constructed emotion [11,12], the core ideas of basic emotion theory remain highly influential in the affective sciences [13,14].

The concept of basic emotions is rooted in functionalist theories, which emphasize their adaptive role in navigating fundamental life tasks. For example, happiness signals progress toward valued goals, while sadness reflects experiences of loss or failure [15]. In depression, adaptive emotional processing is disrupted, characterized by increased negative affect and reduced positive affect [16]. Individuals with depression report significantly lower levels of happiness and heightened sadness when compared to healthy controls [17]. However, there is a dearth of studies dedicated to the experience of different basic emotions in depressed patients.

The emotional profile of depression is distinct from that of non-patients, primarily marked by heightened sadness, which aligns with core diagnostic criteria for depressive episodes [18]. However, other negative emotions like fear and anger are also reported, indicating broader emotional dysregulation in depressive states [5,19]. Depressed individuals often show significantly lower frequencies of happiness and higher levels of sadness, alongside an increased experience of fear and anger compared to non-depressed individuals [5,20]. This specific emotional pattern might serve as a key differentiator between depressive disorders and other mood disorders. The hierarchy of emotional responses in depression, typically led by sadness and followed by fear and anger, indicates a unique affective profile. While sadness is the most frequently experienced emotion, heightened levels of fear and anger reflect a broader spectrum of negative affectivity [19]. These findings underscore the importance of exploring a range of basic emotions in understanding the emotional dysregulation inherent in depression, which can inform more targeted and effective therapeutic interventions.

Dual-process theories distinguish between two types of information processing: a reflective, conscious system that handles information in a linear, step-by-step manner, and an impulsive, automatic system that operates outside of conscious awareness and processes information simultaneously [21]. Self-report affect measures assess what is known as explicit affect, referring to conscious emotional experiences shaped by intentional reflection and social norms regarding emotional expression [22]. On the other hand, implicit affect arises from the impulsive processing system, reflecting immediate, automatic emotional responses. This type of affect is thought to involve the rapid activation of extensive emotional information, including both episodic and declarative memory [22,23]. Implicit emotions involve the automatic activation of cognitive representations of affective experiences, functioning through non-conscious, associative processing systems [22]. In recent years, the study of implicit emotions has received increasing attention due to its potential to reveal automatic, non-conscious emotional processes not easily captured by traditional self-report measures [24,25,26].

The Implicit Positive and Negative Affect Test (IPANAT) was designed to assess these non-conscious emotional states. It measures implicit positive and negative affect by asking participants to rate meaningless stimuli based on perceived emotional connotations, effectively bypassing self-report biases [22]. Factor analyses identified two main factors, implicit positive affect and implicit negative affect, each demonstrating high internal consistencies and reliabilities [23]. The validity of the IPANAT is supported by substantial empirical evidence. The IPANAT has shown criterion validity, correlating with physiological stress markers and distinguishing between implicit and explicit affect. Notably, implicit affect assessed by the IPANAT is linked to automatic physiological responses, such as cortisol levels, suggesting it captures underlying affective processes beyond conscious self-reports [27]. Moreover, implicit negative affect measured by the IPANAT was found to be associated with the recognition of masked (or hidden) angry body expression and enhanced activation of emotion-processing subcortical structures in response to masked (or hidden) angry and fearful body postures [28].

Building on the IPANAT, a procedure to assess the specific basic emotions—happiness, sadness, anger, and fear—called the IPANAT for Discrete Emotions (IPANAT-DE, refs. [23,29]) was developed. A yet unpublished version of the IPANAT-DE showed a robust factor structure with high internal consistencies (all Cronbach’s alphas > 0.80) and captured effects specific to distinct emotions using subliminal stimuli [23,29]. In addition, implicit affect, as measured by the IPANAT-DE, was found to be linked to physiological indicators of stress: van der Ploeg et al. [30] observed that higher levels of implicit negative affect correlate with increased systolic blood pressure and decreased heart rate variability during stress tasks, indicating a connection between non-conscious emotional processes and cardiovascular reactivity. Günther et al. [31] demonstrated that implicit anxiety as measured by the IPANAT-DE is predictive of increased activation in the basolateral amygdala during the presentation of masked fearful faces.

Suslow et al. [32] studied changes in implicit and explicit affect in patients with clinical depression during an inpatient treatment program using the IPANAT. During the acute phase of depression, patients exhibited significantly lower positive affect and heightened negative affect compared to healthy controls. After seven weeks of treatment, both implicit and explicit positive affect showed improvement, while explicit negative affect significantly decreased. However, implicit negative affect remained largely stable throughout the treatment period. These findings suggest that implicit affectivity may respond differently to therapeutic interventions compared to explicit affect. Specifically, while explicit negative affect tends to decrease with treatment, implicit negative affect remains stable, potentially indicating an increased negative affective responsivity at an automatic processing level in depression that might require long-term interventions for change. This highlights the complexity of treating depressive symptoms, as addressing automatic, unconscious affective processes may be essential for comprehensive recovery.

Emotion psychology has identified four key traits in emotional processing: clarity, attention, intensity, and expression [33]. Of these, emotional clarity—the ability to accurately identify and differentiate emotions—is fundamental for psychological well-being and effective emotion regulation [34,35,36]. High emotional clarity is associated with better psychological and physical health [37,38]. Deficits in clarity, on the other hand, are linked to multiple forms of psychopathology such as anxiety and depression [39,40,41].

Emotional clarity and attention both involve engaging with one’s emotions, but their impacts differ significantly. In contrast to emotional clarity, attention to emotions focuses on simply noticing one’s emotions without necessarily understanding them. High attention without clarity can amplify emotional distress, resulting in maladaptive behaviors like rumination, which increase negative feelings instead of resolving them [33,39]. The ability to understand one’s emotions appears to constitute a building block for successful, adaptive emotion regulation [42]. Identifying one’s emotions could provide information about possible courses of action, may have a positive influence on decision-making, and may help to shift one’s attention away from goal-irrelevant or distressing stimuli [39,43]. Furthermore, clearly identified emotions could feel less aversive than unclear emotions and help to accept negative emotional states, at least temporarily [44]. Enhancing clarity may thus serve as a protective factor against the onset of mood disorders and improve overall well-being [45]. Interventions that focus on improving emotional clarity can reduce the level of depressive symptoms in chronic depression [46] and help prevent the continuity of depression from adolescence into adulthood [45,47]. These findings emphasize the importance of addressing clarity deficits rather than merely increasing emotional awareness, making it a central focus of clinical interventions.

Emotional clarity and attention to emotions can be assessed using the WEFG (Skalen zur Wahrnehmung eigener und fremder Gefühle) developed by Lischetzke et al. [48]. Lischetzke et al. [48] emphasize that the perception of one’s own emotions can be structured through the dimensions of emotional self-awareness and clarity of one’s own emotions. This conceptual distinction has been successfully applied to the perception of others’ emotions [49].

In our study, we investigated self-reported, explicit basic emotions in depressed patients during acute illness and inpatient treatment. Based on the results of previous studies [17,32], it was hypothesized that depressed patients, when acutely ill, are characterized by reduced explicit happiness and heightened explicit sadness, anxiety, and anger compared to healthy individuals. At the end of the treatment, it was expected that explicit happiness would increase and explicit sadness, anxiety, and anger would decrease in depressed patients [32]. For exploratory purposes, we investigated implicit basic emotions in depressed patients by administering the IPANAT-DE. In the present study, we examined the relationship between changes in emotional clarity and changes in explicit and implicit emotions and depressive symptoms. It was assumed that increases in emotional clarity are correlated with declines in depressive symptoms and in explicit and implicit negative emotions and increases in explicit and implicit happiness. Finally, we explored the relationships between explicit and implicit emotions in acute and partially remitted depressed patients and in healthy individuals at time 1 and time 2. As self-report questionnaires rely on reading and understanding, we decided to administer a measure of verbal intelligence in our study. This allowed us to control whether the study groups differed in their verbal abilities.

2. Materials and Methods

2.1. Participants

Our study sample included 52 patients (30 women) admitted to and treated in the Department of Psychiatry, Psychotherapy and Psychosomatics at the Martin Gropius Krankenhaus Eberswalde. Patients were tested soon after admission and then again after 6 to 8 weeks of treatment. The mean number of days between measurement 1 and measurement 2 was 50.5 (SD: 3.8). We used the Structured Clinical Interview for DSM-5 Disorders (SKID-5-CV [50]) to determine psychiatric diagnoses. All participating patients fulfilled the criteria for major depressive disorder [51]. Patients with a history of or current substance dependence or substance abuse, bipolar disorders, schizophrenia spectrum disorders, neurological diseases, and organic impairments were excluded from the study. Seven patients had an additional anxiety disorder. Forty-nine patients were on antidepressant medication (atypical antidepressants, selective serotonin reuptake inhibitors, serotonin-noradrenaline reuptake inhibitors, or tricyclic antidepressants). In about 46% of the patients, the current depressive episode was the first occurrence of major depression (n = 24). The mean number of depressive episodes was 2.10 (SD = 1.42). In our patient sample, the duration of the index episode was on average 7.31 months (SD = 5.74), whereas the mean total duration of illness was 6.62 years (SD = 7.57). The average age of onset was 38.33 years (SD = 13.34).

All patients took part in a multimodal treatment consisting of group psychotherapy (three times a week) and individual psychotherapy sessions (once a week) in combination with arts and music therapy, physiotherapy, sports, and dietetic treatment. The group psychotherapy consisted of mindfulness training, psychoeducation, and relaxation exercises. Patients were paid a fee for their participation.

The healthy control group consisted of 52 volunteers (32 women). They were recruited via a public notice about the study. Healthy controls were interviewed using the Mini-International Neuropsychiatric Interview (M.I.N.I. [52]). All individuals enrolled in our study as healthy controls met the criterion of having no past or current mental disorder. Healthy individuals were also tested twice at an interval of 6 to 8 weeks. Patients and healthy controls were all native German speakers.

Written informed consent was obtained from all participants prior to enrollment in the study. The study protocol was approved by the Ethics Committee of the Landesärztekammer Brandenburg in Cottbus.

2.2. Measures

The German version [53] of the Differential Emotions Scale (DES [54]) was used in its state form to assess the intensity of currently experienced basic emotions. The DES comprises ten scales measuring ten basic emotions (i.e., happiness, interest, surprise, anger, anxiety, sadness, disgust, shame, guilt, and contempt). Respondents rate the intensity of their momentary emotional experiences on a 4-point scale (0 to 3). In the present investigation, we focused our analysis on the scales assessing happiness, sadness, anxiety, and anger.

Implicit emotions were assessed using the discrete-emotions variant [23] of the Implicit Positive and Negative Affect Test (IPANAT [22]). The IPANAT-DE is an indirect measure of emotions that asks individuals to rate the degree to which artificial words (e.g., VIKES and TUNBA) express emotions. Four basic emotions are assessed: happiness, sadness, anxiety, and anger. Three adjectives are presented per emotion (happiness: freudig (happy), gutgelaunt (cheerful), begeistert (enthusiastic); sadness: traurig (sad), bedrückt (depressed), betrübt (saddened); anxiety: verängstigt (scared), furchtsam (fearful), erschreckt (frightened); anger: verärgert (annoyed), gereizt (irritated), wütend (angry)) along with each of the five words from a putative artificial language. In total, sixty judgments were made on a 6-point scale (1 = does not fit at all; 6 = fits very well). The IPANAT has been shown to have satisfactory internal consistency and factorial validity [23,29].

In the present samples, the IPANAT-DE scales showed satisfactory to excellent internal consistencies. In the patient sample, Cronbach’s alphas were 0.92 (time 1) and 0.92 (time 2) for implicit happiness, 0.92 (time 1) and 0.97 (time 2) for implicit sadness, 0.88 (time 1) and 0.93 (time 2) for implicit anxiety, and 0.77 (time 1) and 0.93 (time 2) for implicit anger. In the healthy control sample, Cronbach’s alphas were 0.96 (time 1) and 0.96 (time 2) for implicit happiness, 0.97 (time 1) and 0.96 (time 2) for implicit sadness, 0.95 (time 1) and 0.94 (time 2) for implicit anxiety, and 0.98 (time 1) and 0.96 (time 2) for implicit anger.

To gather evidence concerning the factorial validity of the IPANAT-DE, we tested a confirmatory factor analysis model to evaluate the factorial structure based on the pooled patient and control subject data from the first measurement (time 1; n = 104). This model specified Positive Affect (implicit happiness) and three lower-order negative emotion factors (implicit anger, implicit anxiety, and implicit sadness) with a higher-order Negative Affect factor. The model achieved a CFI (comparative fit index) = 0.953, TLI (Tucker–Lewis index) = 0.937, RMSEA (root mean square error of approximation) = 0.117, and SRMR (standardized root mean square residual) = 0.052, indicating a good fit in terms of incremental fit indices and an acceptable residual-based fit. Importantly, CFI/TLI are less sensitive than absolute misfit indices to sample-size-related inflation of the chi-square statistic. With a small sample, RMSEA can appear overly strict, whereas the comparatively high CFI/TLI therefore provides a particularly informative indication of model adequacy. Crucially, this model clearly outperformed the traditional two-factor (positive vs. negative emotions) solution (CFI = 0.884, TLI = 0.855, RMSEA = 0.178), supporting the conclusion that negative affect is not adequately represented as a single undifferentiated factor and that discrete negative emotions are factorially distinguishable in the present data.

To assess the dispositional attention to and clarity of one’s own feelings, the WEFG scales (Skalen zur Wahrnehmung eigener und fremder Gefühle) were used [48]. Six items assess emotional clarity (e.g., “I can name my feelings”) and six items measure attention to emotions (e.g., “I focus on how I feel”). Items are rated on a four-point frequency scale. There is evidence for the reliability and (factorial and concurrent) validity of the WEFG scales [48,55].

The Beck Depression Inventory (BDI-II [56]) is a widely used self-report measure of the presence and severity of depressive symptoms. The BDI consists of 21 items assessing the severity of depressive symptoms in the last two weeks. Subjects rate the severity of each symptom on a 4-point scale ranging between 0 and 3.

The Multiple-Choice Vocabulary Intelligence Test (Mehrfachwahl-Wortschatz-Intelligenztest, MWT-B [57]) is a performance test that assesses verbal intelligence. Each of the 37 items consists of one existing word and four pseudo-words (distractor words). Subjects have the task of identifying the real word. The MWT-B sum score can be transformed into IQ scores.

2.3. Procedure

Study participation included an initial interview in which exclusion criteria were checked. At the first test session, participants filled out a sociodemographic data questionnaire followed by the MWT-B. Subsequently, participants were given the BDI-II, WEFG, IPANAT-DE, and DES. After six to eight weeks, participants again completed the BDI-II, WEFG, IPANAT-DE, and DES.

2.4. Statistical Analyses

Chi²-tests and t-tests for independent samples were administered to detect differences between study groups in sociodemographic variables and intelligence. The DES and IPANAT-DE data were analyzed by means of 4 × 2 × 2 mixed ANOVAs with emotion quality (happiness, sadness, anxiety, and anger) and time (test 1 vs. test 2) as within-subjects factors and group (depressed vs. healthy individuals) as a between-subjects factor. To examine the time course of emotional clarity, attention to emotions, and depressive symptoms (BDI-II), we performed separate 2 × 2 mixed ANOVAs with time as a within-subjects factor and group as a between-subjects factor. The Greenhouse–Geisser correction [58] was applied to adjust the degrees of freedom of F-ratios in case the sphericity assumption was violated. For emotional clarity, attention to emotions, BDI-II, and the explicit and implicit emotions (DES and IPANAT-DE) we calculated change scores in the patient sample by subtracting the score after 7 weeks from the baseline score (in the case of BDI-II, sadness, anxiety, and anger) or by subtracting the baseline score from the score after 7 weeks (in the case of emotional clarity, attention to emotions, and happiness). Thus, a positive change score indicated either an increase in positive emotion, emotional clarity, and attention to emotions or a decrease in depressive symptoms or negative emotions. To test our directed hypotheses concerning the relationships between changes in emotional clarity, depressive symptoms, and explicit and implicit emotions, we employed one-sided significance tests but used a conservative p-level of 0.005 in these analyses. Additional exploratory correlation analyses were conducted in the patient sample to examine associations between changes in attention to emotions and changes in depressive symptoms and explicit and implicit emotions. Moreover, exploratory correlation analyses were calculated to investigate associations between explicit and implicit emotions in the patient sample and the healthy control sample. All calculations were performed using IBM SPSS Statistics 29.0 (IBM Corp., Armonk, NY, USA). Results were considered significant at p < 0.05 and were two-tailed if not otherwise specified.

G*Power (version 3.1.9.2.; University of Kiel, Kiel, Germany) [59] was used to perform a priori analyses of statistical power. According to the findings of a previous study [17], the difference in explicit happiness between acutely depressed patients and healthy controls was large, and the difference in explicit sadness was medium to large. A calculation based on MANOVA, repeated measures, F tests, within–between interaction indicated a required total sample size of 90 to detect a medium to large effect size (f (V) = 0.3) given a power (1 − β) of 0.80 and an alpha value of 0.05 (with two groups and two measurements).

3. Results

The study groups did not differ significantly in age, sex ratio, years of school education, and intelligence (see Table 1 for statistical details).

Table 1. Sociodemographic and intelligence test data of depressed patients and healthy controls (means (SD in parentheses) or frequency values).

Variable	Depressed Patients Mean (SD)	Healthy Individuals Mean (SD)	t/χ2	p
Age	44.94 (13.65)	44.73 (12.71)	0.08	0.93
Sex (female/male)	30/22	32/20	0.16	0.69
School education (years)	10.92 (1.23)	11.38 (1.30)	−1.86	0.07
Intelligence (IQ; MWT-B)	110.31 (14.61)	114.46 (17.36)	−1.32	0.19

MWT-B: Multiple-Choice Vocabulary Test Version B.

3.1. Explicit and Implicit Emotions: Longitudinal Analysis

A 4 × 2 × 2 mixed ANOVA based on the DES scores showed a main effect of emotion quality, F (1.40, 143.32) = 77.77, p < 0.001, ηp² = 0.43, and a main effect of group, F (1, 102) = 24.80, p < 0.001, ηp² = 0.20. Moreover, the results indicated an emotion × group interaction, F (1.40, 143.32) = 44.30, p < 0.001, ηp² = 0.30, a time × group interaction, F (1, 102) = 4.72, p < 0.05, ηp² = 0.04, an emotion × time interaction, F (1.91, 194.57) = 12.71, p < 0.001, ηp² = 0.11, and a three-way interaction (emotion × time × group), F (1.91, 194.57) = 13.24, p < 0.001, ηp² = 0.11. The DES scores are shown in Table 2. To further analyze the three-way interaction, separate two-factor ANOVAs (emotion × time) were conducted for both groups. A 4 × 2 ANOVA based on DES scores of depressed patients yielded a main effect of emotion, F (1.44, 73.45) = 7.92, p < 0.005, ηp² = 0.13, and an interaction effect (emotion × time), F (1.98, 100.93) = 18.28, p < 0.001, ηp² = 0.26. According to the results of dependent samples t-tests, explicit happiness increased from time 1 to time 2, t (51) = −5.34, p < 0.001, whereas explicit sadness, anxiety, and anger decreased over time (t (51) = 3.77, p < 0.001; t (51) = 2.66, p < 0.01; t (51) = 2.05, p < 0.05). The results of a 4 × 2 ANOVA based on DES scores of healthy controls showed only a main effect of emotion, F (1.30, 66.33) = 194.56, p < 0.001, ηp² = 0.79. Bonferroni-adjusted pairwise comparisons indicated that explicit happiness was significantly greater than explicit sadness, anxiety, and anger (ps < 0.001). Moreover, explicit sadness scores were higher than explicit anxiety and anger scores (ps < 0.005).

Table 2. Depressive symptoms, emotional clarity, attention to emotions, and explicit and implicit emotions of study groups at the two test sessions (means with SD in parentheses).

	Depressed Patients		Healthy Individuals
	Time 1 Mean (SD)	Time 2 Mean (SD)	Time 1 Mean (SD)	Time 2 Mean (SD)
BDI-II	31.46 A (9.71)	19.79 B (13.39)	5.04 C (4.24)	4.88 C (4.68)
Emotional clarity	14.83 A (3.83)	16.62 B (3.77)	19.98 C (3.18)	19.81 C (3.21)
Attention to emotions	14.73 A (4.21)	16.12 B (4.31)	14.62 A (3.86)	15.04 AB (3.65)
Explicit happiness	0.64 A (0.62)	1.19 B (0.86)	1.54 C (0.69)	1.60 C (0.72)
Explicit sadness	1.25 A (0.82)	0.80 B (0.83)	0.18 C (0.29)	0.28 C (0.49)
Explicit anxiety	0.77 A (0.72)	0.51 B (0.60)	0.09 C (0.29)	0.10 C (0.33)
Explicit anger	0.65 A (0.73)	0.41 B (0.69)	0.06 C (0.14)	0.12 C (0.31)
Implicit happiness	2.85 A (0.84)	3.01 A (0.80)	2.99 A (1.00)	3.06 A (0.94)
Implicit sadness	2.52 A (0.73)	2.55 A (0.85)	2.42 A (1.07)	2.41 A (0.94)
Implicit anxiety	2.36 A (0.79)	2.50 A (0.84)	2.42 A (1.08)	2.22 A (0.94)
Implicit anger	2.54 A (0.75)	2.71 A (0.87)	2.60 A (1.12)	2.41 A (0.95)

BDI-II: Beck Depression Inventory. Mean values in rows marked with different letters differ significantly.

A 4 × 2 × 2 mixed ANOVA based on the IPANAT-DE scores revealed a significant main effect of emotion quality, F (1.89, 192.40) = 32.40, p < 0.001, ηp² = 0.24. No other effect was significant. According to Bonferroni-adjusted pairwise comparisons, implicit happiness was significantly greater than implicit sadness, anxiety, and anger (ps < 0.001). Moreover, implicit anger scores were higher than implicit anxiety scores (p < 0.001). The IPANAT-DE scores are shown in Table 2. To estimate the effect sizes for the differences between groups with regard to implicit emotions, independent t-tests were calculated for both measurement times. As expected, none of the t-tests were significant (all ps > 0.05). Effect sizes for these (non-significant) group differences are presented in Table 3. At time 1, effect sizes indicated very small to small differences between groups in all implicit emotions. At time 2, according to Cohen’s d, group differences were small to very small for implicit happiness and implicit sadness, and medium for implicit anxiety and implicit anger.

Table 3. Effect sizes for group differences between depressed patients and healthy controls concerning implicit emotions at time 1 and time 2 (with confidence intervals).

	Cohen’s d	95% Confidence Interval
		Lower Limit	Upper Limit
Implicit happiness time 1	−0.146	−0.530	0.240
Implicit sadness time 1	0.107	−0.277	0.492
Implicit anxiety time 1	−0.058	−0.443	0.326
Implicit anger time 1	−0.054	−0.438	0.330
Implicit happiness time 2	−0.053	−0.437	0.332
Implicit sadness time 2	0.160	−0.225	0.545
Implicit anxiety time 2	0.315	−0.073	0.701
Implicit anger time 2	0.332	−0.056	0.719

3.2. Emotional Clarity and Attention to Emotions: Longitudinal Analysis

According to the results of a 2 × 2 mixed ANOVA on emotional clarity scores (WEFG), there was a main effect of time, F (1, 102) = 7.95, p < 0.01; ηp² = 0.07, and group, F (1, 102) = 44.45, p < 0.001; ηp² = 0.30, and a time × group interaction, F (1, 102) = 11.73, p < 0.001; ηp² = 0.10. In the patient sample, emotional clarity increased significantly from time 1 to time 2, t (51) = −4.45, p < 0.001, Cohen’s d (repeated measures) = 0.61, whereas no changes in emotional clarity were observed for healthy individuals.

A 2 × 2 mixed ANOVA on attention to emotions scores (WEFG) yielded only a main effect of time, F (1, 102) = 6.28, p < 0.05; ηp² = 0.06. There was an increase of medium effect size in attention to feelings from time 1 to time 2, irrespective of group.

3.3. Depressive Symptoms: Longitudinal Analysis

The results of a 2 × 2 mixed ANOVA based on BDI-II scores indicated main effects of time, F (1, 102) = 64.29, p < 0.001, ηp² = 0.39, and group, F (1, 102) = 172.96, p < 0.001, ηp² = 0.63, as well as a time × group interaction, F (1, 102) = 60.99, p < 0.001; ηp² = 0.37. The BDI-II scores are presented in Table 2. The BDI-II scores of depressed patients were in general higher than those of healthy individuals. However, depressed patients described significantly fewer depressive symptoms at time 2 compared to time 1, t (51) = 8.14, p < 0.001, Cohen’s d (repeated measures) = 1.42.

3.4. Relationships Between Change in Emotional Clarity and Changes in Depressive Symptoms, Explicit and Implicit Emotions in the Patient Sample

The results from our correlation analyses indicated that an increase in emotional clarity was correlated with decreases in depressive symptoms, explicit sadness, and implicit anger and increases in explicit happiness (ps < 0.005; see Table 4 for statistical details). In contrast, there were no correlations between patients’ change in attention to emotions and changes in depressive symptoms, explicit and implicit emotions (see Table 4).

Table 4. Product–moment correlations of change in emotional clarity and attention to emotions with changes in depressive symptoms and implicit and explicit emotions in the patient sample (n = 52) with descriptive statistics (means with SD).

	∆ Emotional Clarity	∆ Attention to Emotions	Mean (SD)
∆ Emotional clarity	1	−0.05	1.79 (2.90)
∆ Attention to emotions	−0.05	1	1.38 (4.46)
∆ Depressive symptoms	0.50 **	−0.09	11.67 (10.34)
∆ Explicit happiness	0.50 **	−0.08	0.54 (0.74)
∆ Explicit sadness	0.35 *	−0.22	0.45 (0.86)
∆ Explicit anxiety	0.23	−0.20	0.26 (0.71)
∆ Explicit anger	0.14	−0.11	0.24 (0.86)
∆ Implicit happiness	0.13	−0.16	0.16 (0.83)
∆ Implicit sadness	0.13	−0.19	−0.03 (0.82)
∆ Implicit anxiety	0.10	0.03	−0.14 (0.87)
∆ Implicit anger	0.35 *	0.00	−0.17 (0.77)

* p < 0.005, ** p < 0.0001 (one-tailed).

3.5. Correlations Between Explicit and Implicit Emotions in Depressed Patients

At time 1, there was a significant positive correlation between explicit and implicit anger in the patient sample. However, no correlations were found between explicit and implicit happiness, explicit and implicit sadness, and explicit and implicit anxiety (see Table 5 for statistical details). Interestingly, at time 1 there were also significant positive correlations of implicit sadness and implicit anxiety with explicit anger. At time 2, no significant correlations were observed between explicit and implicit emotions of the same quality (see Table 5). At time 2, implicit anger was positively correlated with explicit anxiety, and implicit happiness was found to be negatively correlated with explicit anger and explicit sadness.

Table 5. Product–moment correlations between explicit and implicit emotions (A) in the patient sample and (B) in the healthy control sample.

	Implicit Happiness		Implicit Sadness		Implicit Anxiety		Implicit Anger
	Time 1	Time 2	Time 1	Time 2	Time 1	Time 2	Time 1	Time 2
A Patient sample
Explicit happiness
Time 1	−0.01	0.02	−0.18	0.06	−0.15	−0.04	−0.08	−0.06
Time 2	0.05	0.26	0.03	−0.01	0.09	−0.01	0.08	−0.23
Explicit sadness
Time 1	0.07	−0.05	0.12	−0.06	0.22	0.03	0.27	0.11
Time 2	−0.11	−0.37 **	−0.13	−0.11	−0.04	−0.06	−0.03	0.22
Explicit anxiety
Time 1	−0.03	−0.08	0.09	0.01	0.17	0.02	0.04	0.00
Time 2	−0.02	−0.11	0.00	0.11	0.11	0.17	0.11	0.34 *
Explicit anger
Time 1	−0.10	−0.12	0.27 *	0.01	0.31 *	0.01	0.30 *	0.05
Time 2	−0.18	−0.38 **	−0.10	−0.08	0.05	−0.10	0.01	0.24
B Healthy sample
Explicit happiness
Time 1	−0.13	−0.08	−0.09	−0.26	−0.16	−0.18	−0.08	−0.24
Time 2	0.05	0.03	0.09	−0.09	0.04	−0.07	−0.06	−0.03
Explicit sadness
Time 1	−0.07	−0.15	−0.13	0.03	−0.02	0.09	−0.09	0.09
Time 2	−0.28 *	−0.22	−0.22	−0.11	−0.20	−0.06	−0.21	−0.14
Explicit anxiety
Time 1	−0.07	−0.11	−0.18	−0.09	−0.07	0.09	−0.10	0.14
Time 2	−0.37 **	−0.36 **	−0.27	−0.26	−0.19	−0.15	−0.22	−0.15
Explicit anger
Time 1	−0.17	−0.17	−0.22	−0.22	−0.19	−0.15	−0.16	−0.08
Time 2	−0.06	−0.09	−0.17	0.01	−0.08	0.06	0.05	0.02

* p < 0.05, ** p < 0.01 (two-tailed).

3.6. Correlations Between Explicit and Implicit Emotions in Healthy Individuals

Neither at time 1 nor at time 2 were there significant correlations between explicit and implicit emotions of the same quality in the healthy control sample (see Table 5 for details).

4. Discussion

This study examined explicit and implicit basic emotions, emotional clarity, and attention to emotions in depressed patients over a seven-week inpatient treatment period. It should be noted that the results concerning implicit emotions should be considered exploratory due to the ongoing validation process of the discrete emotion variant of the IPANAT administered in our study. By investigating both explicit and implicit representations of basic emotions during the acute phase of illness and subsequent recovery, the study may offer a differentiated perspective on emotional processes in depressed patients in an important period of their illness. Furthermore, the study investigated the relationship between patients’ emotional clarity and attention with basic emotions and depressive symptoms during inpatient treatment. This dual-focus investigation may contribute to a more nuanced understanding of emotional characteristics in depression.

As hypothesized, depressed patients showed significantly lower levels of explicit happiness and higher levels of explicit sadness, anxiety, and anger compared to healthy controls at treatment onset. This is in line with previous findings [17,20]. The explicit emotion profile strongly aligns with the core diagnostic criteria for depression, particularly the persistence of negative affect and diminished positive affect [51]. The heightened sadness observed in depressed patients is consistent with prior research emphasizing sadness as a hallmark of depressive states [5,19]. However, the heightened levels of explicit anxiety and anger extend the emotional profile of depression, suggesting broader negative emotional dysregulation beyond sadness alone.

The pattern of group differences for explicit emotions persisted at the end of treatment, but happiness increased, while sadness, anxiety, and anger decreased in the patient group over the seven-week period. This means that our hypotheses concerning group differences and change over time in the depressed group were confirmed for explicit emotions. Explicit emotions in the depressed group improved significantly during the treatment period. These findings corroborate prior studies demonstrating that psychotherapy and pharmacotherapy effectively reduce negative affectivity and increase positive affect in depression [60,61]. The multimodal treatment employed in this study, combining psychotherapy, arts therapy, mindfulness training, and relaxation techniques, likely contributed to these improvements.

Interestingly, our data on implicit emotions show a different picture. Depressed patients did not differ from healthy controls in implicit emotions across both measurements. Both study groups manifested a stable pattern of implicit emotions characterized primarily by happiness and fewer negative emotions (i.e., sadness, anxiety, and anger). A predominance of implicit positive affect over implicit negative affect has been observed repeatedly in healthy samples [22,62]. It seems surprising that acutely depressed patients show implicit happiness and implicit negative emotions at levels that correspond to those measured in healthy individuals. In this context, one must consider that implicit emotion scores as measured by the IPANAT appear to reflect both state and trait variance [22,23]. Thus, the IPANAT-DE should not only measure state emotions but also tap trait emotions, i.e., stable tendencies or dispositions to experience basic emotions (such as happiness, sadness, anxiety, and anger) across time and situations (see [22]). The depressive episode as a temporary phenomenon could be accompanied by altered state emotions, but it may not change general predispositions to experience basic emotions. However, it has to be noted that the null findings concerning the IPANAT-DE cannot be interpreted as clear evidence for the absence of implicit emotion alterations in depression. Our effect size analysis helps to make a differentiated interpretation of the null findings. The present effect size results indicate that no substantial differences in implicit emotions should be expected between acutely depressed and healthy individuals. However, less depressed patients (who are in a phase of recovery) may differ in implicit anger and anxiety from healthy individuals to some extent. In these cases, medium effect sizes for differences between depressed and healthy individuals can be expected. A priori power analysis calculated with the program G*Power [59] shows that to detect a medium-sized difference between two independent means (two groups) d = 0.3, given an alpha error probability of 0.05 and a power of 0.80 (one-tailed testing), the required total sample size is 278. This means that future research on implicit anger and anxiety in depression should be based on large samples to have adequate statistical power to detect differences between patients and healthy individuals. Given this estimate, it is clear that our study had low statistical power to detect medium-sized group differences in implicit emotions. Based on the results of the present study and those of Suslow et al. [32], it appears that differences in implicit affectivity between clinically depressed patients and healthy individuals could be detected more readily with the original variant of the IPANAT than with the discrete emotion variant of the IPANAT.

A complementary explanation for our IPANAT-DE findings is based on a dual-process model of depression, which suggests that depression is linked to an overreliance on explicit, analytical processing—developing later in childhood and fostering rumination—while suppressing the implicit, experiential self-system, which emerges earlier and is associated with implicit self-esteem [63,64]. Previous studies have shown that individuals with depression differ from healthy individuals in explicit but not implicit self-esteem [65,66,67]. This suggests that acutely depressed patients maintain positive implicit self-esteem. Implicit self-esteem is thought to be shaped by early learning processes and self-schemata formed in infancy and childhood, in which generally positive self-evaluations are encoded [68,69]. In our sample, less than a quarter of patients were characterized by an early onset of depressive illness (age of first onset of clinical depression ≤ 25 years). This suggests that for most patients, the later onset of illness may have allowed for a largely normal development of trait emotions.

The present findings concerning implicit emotions in depressed patients are inconsistent with the results from a previous longitudinal study [32], which found that acutely depressed patients are characterized by decreased implicit positive affect and increased implicit negative affect compared to healthy individuals. The authors observed that after seven weeks of treatment, depressed patients’ implicit positive affect increased, whereas their implicit negative affect remained unchanged. A possible reason for the differences between studies could lie in the different versions of the test used. In the present investigation, the IPANAT-DE was administered, which represents a measure of basic emotions. Suslow et al. [32] applied instead the IPANAT that was constructed to assess implicit positive affect (on the basis of the mood-related adjectives “happy”, “energetic”, and “cheerful”) and implicit negative affect (using the adjectives “helpless”, “tense”, and “inhibited”). It is possible that the IPANAT adjectives, especially “energetic” and “helpless”, are more sensitive to capturing depression-related emotional states compared to the IPANAT-DE. Other reasons for the discrepancy in results between the present study and that of Suslow et al. [32] could lie in the lower rate of antidepressant medication (69% (Leipzig sample) vs. 94% (Eberswalde sample)) and a more severe disease history of the patients examined in Leipzig (although the patients in Leipzig were on average 13 years younger than our patients). The mean duration of the index episode was 12.7 months for patients examined in Leipzig (vs. a mean duration of 7.3 months for our patients). Moreover, the mean number of depressive episodes was 3.0 for the patients examined in Leipzig, whereas the mean episode number was 2.1 for our patients. More severe (or chronic) forms of depressive disorders could be more associated with increases in implicit negative affect and reductions in implicit positive affect than milder (or less chronic) forms. In addition, antidepressant medication may positively influence implicit affectivity. Including more unmedicated depressed patients in a sample could increase the likelihood of detecting alterations in implicit emotions.

Given our findings, it is not surprising that we observed almost no correlations between explicit and implicit emotions of the same quality in our study. The only correlation we found was between explicit and implicit anger in acutely depressed patients (at the start of the treatment). Moreover, we observed correlations between explicit and implicit negative emotions only in patients: at time 1, implicit sadness and implicit anxiety were positively correlated with explicit anger, and at time 2, implicit anger was correlated with explicit anxiety. In general, explicit and implicit emotions, as assessed by the IPANAT, seem to be rather independent of each other [26,63]. Interestingly, in the longitudinal study by Suslow et al. [32], no correlations between implicit and explicit affect were observed for healthy individuals and for depressed patients in the recovery phase, but in the state of acute depression, patients manifested correlations between implicit negative affect and explicit negative state and trait affect. Thus, in the state of depression, as our data on correlations between explicit and implicit emotions also suggest, the interplay between the reflective and automatic systems could be increased for negative affectivity. This observation can be interpreted in the context of hyperconnectivity between limbic (anterior cingulate cortex) and (medial) prefrontal structures that has been found in depressed patients compared with healthy individuals [70,71]. The anterior cingulate cortex is assumed to gate the access of information on basic emotional responses into prefrontal structures, which are involved in processes of conscious emotional awareness [72,73]. In the state of depression, limbic and medial prefrontal structures (i.e., automatic and reflective emotion processing structures) could be more strongly coupled, not least because depression seems characterized by hypoactivity in prefrontal brain regions associated with cognitive control during emotion regulation [74].

Emotional clarity, defined as the ability to accurately identify and differentiate emotions, seems to be an important factor in the treatment of depression [46]. In our study, depressed patients exhibited significantly lower levels of emotional clarity at baseline compared to healthy controls, consistent with prior findings linking deficits in emotional clarity to depression or depressive symptoms [39,40,45]. Over the course of treatment, emotional clarity improved significantly in the patient group, and this improvement was accompanied by reductions in depressive symptoms, explicit sadness, and implicit anger, as well as increases in explicit happiness. This means that increases in emotional clarity were not only correlated with increases in explicit happiness and decreases in depressive symptoms and explicit sadness but also with a reduction in implicit anger. This could indicate that when patients’ emotional clarity increases, automatic activation of anger responses and cognitive representations of anger experiences diminish.

These results highlight the role of emotional clarity as a factor influencing emotional well-being. High emotional clarity is linked to decreased use of maladaptive emotion regulation strategies [36,75]. Conversely, deficits in clarity contribute to emotional confusion and perpetuate negative affective states, exacerbating depressive symptoms. The treatment of depression may profit from greater attention to understanding one’s emotions, breaking the vicious cycle between low emotional clarity and depression symptoms [41]. Interventions aimed at enhancing emotional clarity, such as emotion-focused therapy or mindfulness-based practices, could play an important role in reducing emotional dysregulation and fostering recovery from depression.

Interestingly, in our study, changes in emotional clarity were not correlated with changes in attention to emotions. This finding supports the distinction between these constructs, as attention to emotions involves noticing emotional states but does not necessarily enhance understanding or differentiation [33]. Excessive attention without clarity can lead to heightened emotional distress and maladaptive responses, emphasizing the need to prioritize clarity over mere awareness of emotions in therapeutic settings [55].

5. Limitations

This study has a number of limitations that should be acknowledged. First, it must be pointed out that our findings on implicit emotions are preliminary and exploratory, as the IPANAT-DE represents an innovative test instrument that requires further research for validation. The relatively small sample of mainly middle-aged inpatients of mixed chronicity clearly limits the generalizability of our findings. The findings on implicit emotions in our depressed patient sample, which predominantly had a late onset of the disease cannot be generalized to patients with an early onset of the depressive disorder. Future studies should investigate whether patients with adolescent or early-onset depression exhibit altered implicit emotions compared to healthy individuals. Moreover, our findings cannot be generalized to depressed patients who do not suffer from any comorbid mental disorder or who suffer from comorbid mental disorders other than anxiety disorders. Our depressed patient sample had a mean total illness duration of 6.62 years. Thus, our findings cannot be generalized to depressed patients who are experiencing the illness for the first time and only for a short period, or to patients who have repeatedly experienced depressive episodes over decades. Our patient sample consisted predominantly of medicated patients, so our study results cannot be generalized to unmedicated patients. It should be noted that there are differences between our study groups regarding the recruitment procedure: patients were approached in the hospital, while healthy individuals responded to public notices.

Reliance on self-report measures for explicit emotions can be criticized as it introduces potential biases related to introspective accuracy. The lack of assessing objective emotional indicators of discrete emotions, such as behavioral measures of emotional expression or physiological parameters (e.g., heart rate variability), represents an important methodological limitation of our investigation. Combining self-report with behavioral and physiological indices provides a much more comprehensive assessment of emotional processes [27,30]. The study’s focus on a relatively short treatment period may have limited our chances to detect changes in implicit emotions. Long-term studies examining the effects of extended interventions on both explicit and implicit emotions are needed to enhance our understanding of their changes and interdependencies. Thompson et al. [76] observed that depressed patients have lower clarity of negative, but not of positive, emotions. It is a limitation of our study that we assessed emotional clarity as a unitary construct in our investigation. It is important to distinguish between clarity of positive emotions and clarity of negative emotions. Our unitary assessment of emotional clarity limits the specificity of conclusions regarding its relationship with discrete emotions. It also has to be acknowledged that expectancy effects and demand characteristics may account for part of the changes observed in self-report measures. Against this background, it seems advisable to administer measures of social desirability in future research based on self-report data to help detect and statistically control potential biases arising from both expectancy effects and demand characteristics. It is another study limitation that we administered a multimodal therapeutic program consisting of several simultaneously applied treatment components. Thus, it remains unclear which component may have contributed to improvements in symptoms and affectivity and increases in emotional clarity, and to what extent.

6. Conclusions

Acutely depressed patients showed lower levels of explicit happiness and higher levels of explicit sadness, anxiety, and anger compared to healthy individuals. Over the seven-week treatment period, patients’ happiness increased, while sadness, anxiety, and anger decreased. Heightened levels of explicit anxiety and anger during the acute phase of the illness indicate broader alterations in negative emotions in depression beyond sadness alone. Concerning implicit emotions, depressed patients did not differ from healthy controls. Both groups manifested a stable implicit emotion pattern characterized primarily by happiness and fewer negative emotions. Future studies should reexamine implicit emotions in clinical depression and, to this end, use both the IPANAT-DE and the IPANAT. In this way, it could be clarified whether depressed patients exhibit no changes in implicit basic emotions as assessed by the IPANAT-DE but show alterations in depression-related implicit emotional states as measured by the IPANAT (i.e., increased implicit negative affect and diminished implicit positive affect compared to healthy individuals). Increases in patients’ emotional clarity over the course of treatment seem to co-occur not only with increases in explicit happiness and decreases in depressive symptoms and explicit sadness but also with reductions in implicit anger. Increases in patients’ emotional clarity seem to be correlated with changes not only in explicit but also in implicit affectivity.