Psychometric Properties of the Turkish Intolerance of Uncertainty Index-A in a High-Risk Clinical Adolescent Sample

Abstract

Objective: Intolerance of uncertainty (IU) is a transdiagnostic cognitive construct associated with anxiety, emotional dysregulation, and psychopathology across multiple clinical conditions. This study aimed to adapt the Intolerance of Uncertainty Index A (IUI-A) into Turkish and evaluate its psychometric properties in a high-risk clinical adolescent sample. Methods: One hundred forty adolescents aged 12–17 years (Mage = 15.71, SD = 1.39; 84.3% female) were recruited from a Child and Adolescent Psychiatry Outpatient Clinic. The sample comprised adolescents presenting with suicidal ideation without a prior attempt (SI; n = 42, 30%) or a history of at least one suicide attempt (SA; n = 98, 70%). The majority met criteria for at least one psychiatric diagnosis, with depressive disorder (77.1%) and anxiety-spectrum conditions most prevalent. Analyses included exploratory and confirmatory factor analysis, internal consistency estimation, and assessments of convergent, discriminant, and known-groups validity. Results: EFA supported a two-factor model (Inhibitory IU and Prospective IU) explaining 61.04% of the variance. CFA indicated partially acceptable fit (χ²/df = 2.48, RMSEA = 0.102, CFI = 0.900, TLI = 0.882, SRMR = 0.054), with RMSEA and TLI falling outside conventional thresholds. Internal consistency was strong (α = 0.933, ω = 0.935). IUI-A scores correlated strongly with the IUS-12, and the SA group scored significantly higher on both IU subscales, with group differences persisting after adjustment for key covariates. Conclusion: The Turkish IUI-A provides preliminary, though methodologically provisional, evidence of validity and reliability for assessing IU in high-risk adolescent populations, with several limitations requiring further investigation.

1. Introduction

Uncertainty is an inescapable feature of human experience, yet individuals vary markedly in their capacity to tolerate it. Intolerance of uncertainty (IU) was originally conceptualized as a broad dispositional tendency reflecting negative cognitive, emotional, and behavioral reactions to uncertain everyday situations [1]. Subsequent theoretical refinements culminated in Carleton’s (2016) influential definition, which describes IU as an “individual’s dispositional incapacity to endure the aversive response triggered by the perceived absence of salient, key, or sufficient information, and sustained by the associated perception of uncertainty” [2]. Regardless of how uncertainty is measured objectively, individuals high in IU consistently perceive ambiguous situations as threatening and unacceptable, irrespective of the actual probability of a negative outcome [3,4].

Since its introduction in the mid-1990s, IU has been reconceptualized from a cognitive vulnerability specific to generalized anxiety disorder (GAD) into a transdiagnostic factor implicated across a broad range of psychopathologies, including obsessive–compulsive disorder, social anxiety disorder, depression, and post-traumatic stress disorder [5]. This transdiagnostic conceptualization is substantiated by an accumulating body of meta-analytic evidence extending well beyond anxiety disorders. A meta-analysis encompassing generalized anxiety disorder, major depressive disorder, and obsessive–compulsive disorder demonstrated moderate-to-strong associations between IU and symptoms across all three diagnostic categories, challenging earlier assumptions that IU was specific to GAD [6] This pattern was substantially extended by a larger meta-analysis examining IU across seven syndromes—generalized anxiety disorder, social anxiety disorder, panic disorder, agoraphobia, obsessive–compulsive disorder, depression, and eating disorders—which similarly found moderate-to-strong associations across this diverse range of conditions [7]. More recently, the transdiagnostic relevance of IU has been extended to psychotic-spectrum presentations [8] and chronic physical conditions: a study of patients with type 1 diabetes demonstrated that IU, together with alexithymia, constitutes a significant psychological determinant of adaptive functioning, highlighting the construct’s relevance beyond traditional psychiatric classifications and into the domain of chronic illness management [9]. Within youth populations specifically, IU has also been implicated as a mechanism linking early adversity to suicide risk [10]. Taken together, this body of evidence reinforces the conceptualization of IU as a broad transdiagnostic vulnerability factor, underscoring the value of psychometrically sound, age-appropriate IU assessment tools such as the IUI-A. Research suggests that high IU is associated with a tendency to engage in maladaptive coping strategies—such as excessive worry, reassurance-seeking, and behavioral avoidance—as attempts to regain a sense of control over inherently unpredictable situations [4,11]. The transdiagnostic nature of IU has motivated growing interest in its early identification and treatment as a single mechanism that may reduce vulnerability across multiple co-occurring disorders simultaneously.

A key theoretical development in IU research was the identification of two distinct but related dimensions. Birrell et al. [12] conducted a systematic review of factor-analytic studies and proposed that IU comprises prospective IU—a future-oriented tendency to seek predictability and avoid uncertain situations before they arise—and inhibitory IU—a paralysis of cognition and behavior when uncertainty cannot be avoided. These two dimensions, assessed by the widely used Intolerance of Uncertainty Scale-12 (IUS-12) [3], show distinct but correlated associations with psychopathology: prospective IU is more closely tied to excessive worry and GAD symptoms, whereas inhibitory IU is more strongly associated with avoidance, emotional dysregulation, and broader functional impairment.

The trait-like status of IU is further supported by evidence regarding its developmental origins. Research examining the etiology of IU has highlighted insecure attachment as a key antecedent: children who experience inconsistent or unresponsive caregiving develop working models of the world as unpredictable and threatening, which may predispose them to heightened IU across development. A systematic review and meta-analysis of insecure attachment and child anxiety confirmed that attachment insecurity is robustly associated with anxiety disorders in childhood [13], a pattern that aligns with the conceptualization of IU as a dispositional sensitivity to uncertainty that may be shaped by early attachment experiences. Consistent with this, studies with adolescent populations have found that attachment anxiety mediates the relationship between insecure attachment and IU, suggesting a developmental pathway from early relational experiences to the acquisition of uncertainty intolerance as a stable cognitive–affective trait [14]. These findings underscore the importance of assessing IU in clinical adolescent samples, where attachment-related vulnerabilities are likely to interact with psychiatric presentations.

Adolescence represents a developmentally sensitive period for the emergence of IU-related difficulties. During this stage, maturation of the prefrontal cortex and anterior cingulate cortex—regions central to uncertainty processing and cognitive appraisal—remains incomplete, rendering adolescents particularly susceptible to distress in ambiguous situations [15]. Empirical studies consistently link elevated IU in youth to heightened anxiety, depression, OCD symptoms, emotion dysregulation, and social withdrawal [15,16]. Importantly, IU has been shown to mediate the relationship between emotion regulation difficulties and anxiety symptoms in non-clinical adolescents, underscoring its role as a bridge between affective dysregulation and psychopathological outcomes in this age group [17]. The applicability of the IU cognitive–behavioral model to GAD symptoms in young people aged 11–15 has also been empirically supported, with IU and negative problem orientation emerging as significant predictors of generalized anxiety symptoms [18]. A novel network approach to conceptualizing IU in a large sample of 5672 Chinese adolescents further revealed that prospective IU—specifically the tendency to experience anticipatory distress about future uncertainty—functions as a central hub symptom with the highest strength centrality in the IU network, suggesting it may play a key activating role in sustaining IU-related distress during adolescence [19]. This developmental vulnerability is corroborated by meta-analytic evidence specific to younger populations: a meta-analysis of IU, anxiety, and worry in children and adolescents confirmed a robust positive association between IU and both anxiety and worry symptoms across childhood and adolescence, with effect sizes comparable to those observed in adult samples [20]. Of particular clinical relevance, accumulating evidence suggests that IU has been associated with self-harm and suicidal behavior, potentially through its links with emotional dysregulation and impaired coping. Individuals with high IU exhibit abnormal responses to uncertain outcomes and are more likely to engage in maladaptive coping strategies that have been associated with escalating psychological distress toward suicidal ideation or attempts [21,22]. Suicide is the second leading cause of death among young people globally, and identifying modifiable correlates such as IU in clinical adolescent populations is of considerable public health relevance.

Beyond its clinical implications, IU carries significant consequences for adolescent functioning within educational settings. School environments are inherently characterized by uncertainty—academic performance expectations, transitions between educational stages, peer group dynamics, and evolving social hierarchies all constitute sources of ambiguity that may be particularly distressing for youth high in IU. Research conducted with Turkish high school students has demonstrated that IU directly and indirectly—through educational stress—adversely affects academic life satisfaction [23]. Relatedly, studies show that elevated IU reduces academic engagement and predicts academic burnout in students by depleting cognitive self-regulatory resources [24]. Furthermore, IU has been found to predict decisional procrastination in academic contexts, with prospective IU serving as a significant mediator between academic self-efficacy and avoidant decision-making behaviors [16]. Adolescents who struggle to tolerate uncertainty may experience heightened emotional reactivity during educational transitions and evaluative situations, rendering them vulnerable to academic disengagement and social difficulties with peers. These educational and social challenges underscore the importance of identifying IU not only in clinical settings but also within school-based mental health support systems. School counselors and educators equipped with valid, culturally appropriate IU assessment tools are better positioned to identify at-risk students early and implement preventive interventions before clinical-level distress develops.

The growing recognition of IU as a transdiagnostic vulnerability factor has motivated development of several age-appropriate assessment tools, including the Intolerance of Uncertainty Scale for Children (IUSC) [25], its short form (IUSC-12) [26] the revised Intolerance of Uncertainty Scale (IUS-R) [27] and the Intolerance of Uncertainty Index–Part A for Children (IUI-A) [28]. A key distinction relevant to the present study concerns the differential contribution of the IUI-A relative to the IUS-12, which has been validated in Turkish by Sarıçam [29]. The IUS-12 is an adult-oriented measure not designed for children and adolescents, whereas the IUI-A was specifically developed and validated for youth aged 7–17 using developmentally sensitive item wording and demonstrated strong internal consistency, convergent validity, and test–retest reliability in its original validation [28]. Validated translations of the IUI-A remain limited to a small number of cultural contexts, with no Turkish adaptation available for use in clinical adolescent populations. Turkey faces an increasing burden of adolescent psychiatric presentations, and clinicians working in child and adolescent psychiatry settings lack a psychometrically sound, age-appropriate tool to assess IU. The present study addresses this gap by adapting the IUI-A into Turkish and evaluating its psychometric properties in a clinical sample of adolescents presenting with suicidal ideation or a history of suicide attempts.

This study aimed to translate, adapt, and examine the psychometric properties of the IUI-A in a Turkish clinical adolescent sample. Specifically, we aimed to: (1) evaluate the factor structure through exploratory (EFA) and confirmatory factor analysis (CFA); (2) assess internal consistency using Cronbach’s alpha and item-total correlations; (3) examine convergent validity by correlating IUI-A scores with the Turkish IUS-12 [29]; (4) assess discriminant validity using the Parental Attitude Scale; and (5) evaluate known-group validity by comparing IU levels between adolescents with suicidal ideation and those with a history of suicide attempts. A clinical sample with suicidal presentations was selected for this initial validation because it represents a high-need population in which a reliable IU measure could have immediate clinical utility, and because existing research suggests elevated IU in youth with suicidal ideation and attempts [10,21]. The Turkish IUI-A is intended primarily as a research and clinical screening instrument for IU in adolescent psychiatric populations; it is not designed to provide diagnostic classifications, clinical cut-offs, or standalone risk predictions. By providing a preliminary Turkish version of the IUI-A, this study contributes to the growing body of cross-cultural IU research and offers a potentially useful tool for early identification in high-risk adolescent populations, pending further validation.

2. Methods

2.1. Participants

The study included 140 adolescents aged 12–17 years (Mage = 15.71, SD = 1.39, range = 12.33–17.91). The sample comprised predominantly female adolescents (n = 118, 84.3%; male n = 22, 15.7%) presenting with either suicidal ideation without any lifetime history of suicide attempt (SI group; n = 42, 30%) or at least one confirmed prior suicide attempt (SA group; n = 98, 70%); suicidal ideation and attempt status were established using the C-SSRS. Educational level was high school for most participants (n = 121, 86.4%), with the remainder attending middle school (n = 19, 13.6%). All participants were assessed using the K-SADS-PL [30]. The most prevalent diagnoses were depressive disorder (n = 108, 77.1%), agoraphobia (n = 35, 25.0%), attention-deficit/hyperactivity disorder (n = 33, 23.6%), panic disorder (n = 24, 17.1%), and post-traumatic stress disorder (n = 16, 11.4%). The vast majority (n = 138, 98.6%) met criteria for at least one K-SADS-PL diagnosis, and 83.6% presented with comorbid conditions. Family psychiatric history was reported by 61 participants (43.9%), and 78 (55.7%) reported a history of traumatic events. Medication and treatment status at the time of assessment were not systematically recorded and could not be reported, which represents a limitation of the present study.

2.2. Measures

To assess the psychometric properties of the Turkish adaptation of the Intolerance of Uncertainty Index A (IUI-A), the following measures were utilized:

Intolerance of Uncertainty Index A (IUI-A). The IUI-A is a self-report measure designed to assess intolerance of uncertainty (IU) in children and adolescents. It consists of 15 items, rated on a 5-point Likert scale (1 = Strongly Disagree to 5 = Strongly Agree), with higher scores indicating greater IU. The original scale demonstrated strong internal consistency and construct validity [28]. This study aimed to evaluate the factor structure, reliability, and validity of its Turkish adaptation.

Intolerance of Uncertainty Scale-12 (IUS-12). The IUS-12 is a validated measure of IU in adolescents and adults, composed of 12 items rated on a 5-point Likert scale. It assesses two established subscales—Prospective Anxiety (corresponding to prospective IU) and Inhibitory Anxiety (corresponding to inhibitory IU)—as distinct but related dimensions of the construct.

Parental Attitude Scale (PAS). The PAS is a widely used measure that assesses parenting styles and attitudes toward children and adolescents. It includes three subscales: acceptance/involvement, psychological autonomy, and behavioral control [31]. The PAS was used to assess discriminant validity on the theoretical grounds that IU, as a cognitive-dispositional trait, is conceptually distinct from parenting style as assessed by the PAS. While some theoretical overlap between parenting dimensions (particularly low psychological autonomy) and IU cannot be excluded—and indeed the observed weak correlations suggest some convergence—the PAS remains the most widely used Turkish instrument for assessing parental attitudes and was selected for pragmatic and comparative reasons. The discriminant validity claim should accordingly be interpreted with caution, given this partial theoretical overlap.

Columbia Suicide Severity Rating Scale (C-SSRS). The C-SSRS is a structured clinical interview designed to assess suicidal ideation and behavior. It includes four subscales evaluating suicidal thoughts, intensity, behaviors, and lethality [32]. This study used C-SSRS to assess known-group validity, comparing IU levels between adolescents with suicidal ideation and suicide attempts. These measures were selected based on their theoretical and empirical relevance to IU, ensuring a comprehensive evaluation of the Turkish IUI-A’s psychometric properties.

2.3. Procedure

The adaptation process followed standard translation and back-translation methodology. Necessary permissions were obtained from the original authors via email. The forward translation was conducted by a bilingual clinical psychologist with expertise in psychological assessment. The back-translation was performed independently by a second bilingual translator who was blind to the original English version. Discrepancies between the original and back-translated versions were reviewed and resolved by a small expert committee (including the study investigators) to ensure linguistic and conceptual equivalence. Formal cognitive interviews or pilot testing with adolescents were not conducted prior to the main data collection, which represents a limitation of the adaptation process; future studies should incorporate structured pilot testing with target-age participants to evaluate item comprehensibility. Ethical approval was granted by the Research Ethics Committee with decision number 2023/0681. After obtaining written informed consent from both participants and their parents, each participant completed the demographic form first, followed by the study scales. Data collection took place at the Child and Adolescent Psychiatry Outpatient Clinic. Systematic data on the number of eligible adolescents approached, refusals, and exclusions were not recorded, which limits the ability to assess recruitment bias. All participants who completed the assessment protocol were included in the final analytical sample.

2.4. Statistical Analysis

Statistical Procedures

Normality of continuous variables was assessed using the Kolmogorov–Smirnov test. Cronbach’s alpha and item-total correlations were used to assess reliability. McDonald’s omega was calculated for each factor and for the total scale as a complementary reliability estimate not dependent on the tau-equivalence assumption [33]; omega was computed from standardized factor loadings derived via single-factor principal axis factoring of each respective item set. Construct validity was evaluated through exploratory factor analysis (EFA; principal-axis factoring, Promax rotation) and confirmatory factor analysis (CFA). The CFA was conducted in Mplus 8.3. The specific estimator was not recorded in the available analysis records and could not be retrospectively verified; based on the Mplus default behaviour when item-level variables are not declared as categorical, the maximum likelihood (ML) estimator was applied by default, treating item responses as continuous indicators. Future validation studies should explicitly specify an estimator appropriate for ordinal data, such as WLSMV [34]. Model fit was evaluated using χ², RMSEA, CFI, TLI, and SRMR. Spearman correlation tests examined convergent and discriminant validity. Mann–Whitney U tests assessed known-groups validity; rank-biserial correlation (rrb) was computed as an effect size estimate, using the formula rrb = 1 − (2U/n₁n₂) [35]. To examine whether group differences persisted after accounting for potential confounders, exploratory general linear models (ANCOVA) were fitted with each IUI-A subscale as the dependent variable, group (SA vs. SI) as the independent variable, and gender, age, depressive disorder diagnosis, trauma history, and any anxiety disorder diagnosis as covariates. These analyses were intended as exploratory sensitivity analyses; formal evaluation of ANCOVA assumptions (residual normality, homoscedasticity, homogeneity of regression slopes) was not conducted, and findings should be interpreted alongside, rather than as replacements for, the unadjusted Mann–Whitney U results. Analyses were conducted using SPSS 25 and Mplus 8.3.

3. Results

3.1. Reliability

The internal consistency of the scale was evaluated using Cronbach’s alpha and item-total correlations. Skewness and kurtosis values were within the expected range [36,37]. Cronbach’s alpha was 0.891 for Factor 1 (Inhibitory IU), 0.898 for Factor 2 (Prospective IU), and 0.933 for the total scale. McDonald’s omega coefficients were ω = 0.897 for Inhibitory IU, ω = 0.899 for Prospective IU, and ω = 0.935 for the total scale, providing a complementary estimate of internal consistency that does not assume tau-equivalence. All item-total correlations were statistically significant and above the recommended 0.30 threshold (ranging from 0.44 to 0.82), indicating strong internal consistency [38]. The descriptive statistics and reliability coefficients are presented in

Table 1. Item-level descriptive statistics and internal consistency indicators for the Turkish IUI-A.

Items	M	SD	S	K	r
1. Gelecekte ne olacağını bilmemek benim için zor bir durumdur.	3.69	1.38	−0.62	−0.89	0.63 *
2. Hayatta ne olacağını bilmemeye katlanamıyorum.	3.38	1.44	−0.35	−1.19	0.75 *
3. Diğer çocuklar gelecekte ne olacağını bilmeme durumuyla başa çıkmakta benden daha iyiler.	3.25	1.64	−0.23	−1.59	0.60 *
4. Hayatta önceden bilemeyeceğim bazı şeylerin olmasına katlanamıyorum.	3.28	1.45	−0.28	−1.23	0.76 *
5. Başıma kötü bir şey gelme ihtimaliyle başa çıkmakta zorlanıyorum.	3.09	1.57	−0.08	−1.54	0.67 *
6. Önemli bir haber beklerken, sonucunu bilmemeyi kabullenmekte zorlanıyorum.	3.60	1.45	−0.64	−1.00	0.68 *
7. Emin olmadığım veya tahmin edilemez durumlarla uğraşmaya dayanamıyorum.	3.64	1.44	−0.75	−0.81	0.76 *
8. Ne olacağını bilmediğim bir durumda kalmaya dayanamıyorum.	3.66	1.42	−0.67	−0.88	0.82 *
9. Gelecekte ne olacağını bilmemekten nefret ediyorum.	3.55	1.56	−0.64	−1.13	0.77 *
10. İlerde ne olacağını bilmediğim zaman beklemeye dayanamam.	3.28	1.50	−0.31	−1.35	0.80 *
11. Hayatta bilinmeyen veya kesin olmayan her şeyle başa çıkmakta zorlanıyorum.	3.44	1.37	−0.45	−0.96	0.81 *
12. Kötü bir şey olabileceğini düşündüğümde, bunun gerçekleşip gerçekleşmeyeceği konusunda kararsız kalmakta zorlanıyorum.	3.70	1.30	−0.60	−0.84	0.67 *
13. Belirsizliktense her şeyi hemen bilmeyi tercih ederim.	3.90	1.34	−0.95	−0.34	0.68 *
14. Beklemediğim bir şeyin olabileceği düşüncesiyle baş etmekte zorlanırım.	3.40	1.45	−0.41	−1.17	0.79 *
15. Bir şeyi yapmayı kabul etmeden önce ondan emin olmam gerekir.	3.74	1.42	−0.68	−0.98	0.42 *
IUI-A Inhibitory IU	31.52	9.57	−0.50	−0.71	0.95 *
IUI-A Prospective IU	21.08	7.06	−0.51	−0.87	0.91 *
IUI-A Total score	52.60	15.64	−0.54	−0.70	-

Note. * p < 0.001, IUI-A = Intolerance of Uncertainty Index-A, M = Mean, SD = Standard deviation, S = Skewness value, K = Kurtosis value.

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3.2. Structural Validity

To test the structural validity of IUI-A, an exploratory factor analysis was conducted using principal-axis factor analysis. The Kaiser–Meyer–Olkin (KMO) value was found to be 0.921, and Bartlett’s chi-square value was χ² = 1337.753, df = 105, p < 0.001. These values indicate that the data is highly suitable for factor analysis. The scree test, conducted after PROMAX rotation, showed the presence of two factors with eigenvalues greater than 1 [39]; Factor 1 = 7.937, Factor 2 = 1.220), explaining 52.912% and 8.133% of the total variance, respectively (Figure 1).

Considering the item contents and previous research findings, Factor 1 was defined as ‘Inhibitory IU’, while Factor 2 was identified as ‘Prospective IU’. We adopt this terminology rather than the ‘Inhibitory/Prospective Anxiety’ labels used for the conceptually related but distinct IUS-12 subscales [3], because the IUI-A items assess intolerance of uncertainty as a cognitive-behavioral disposition rather than anxiety symptoms per se, consistent with the broader theoretical distinction between prospective and inhibitory IU advanced by Birrell et al. [12].

In the next step, confirmatory factor analysis (CFA) was conducted to test the validity of the two-factor structure. The goodness-of-fit indices for the one-factor model were χ² (90, N = 140) = 279.259, p < 0.001, RMSEA = 0.123, CFI = 0.855, TLI = 0.830, and SRMR = 0.060. For the two-factor model, the indices were χ² (89, N = 140) = 219.565, p < 0.001, RMSEA = 0.102, CFI = 0.900, TLI = 0.882, and SRMR = 0.054. The correlation between the two latent factors in the CFA was 0.736 (p < 0.001), indicating a strong but distinct relationship between Inhibitory IU and Prospective IU and consistent with the interpretation of these dimensions as strongly related but potentially separable. It should be noted that two of the fit indices for the two-factor model—RMSEA (0.102) and TLI (0.882)—fell outside the thresholds conventionally recommended for good model fit (RMSEA ≤ 0.08; TLI ≥ 0.90) [40], while the CFI (0.900) and SRMR (0.054) met or exceeded these benchmarks. This pattern of partially satisfactory fit indices warrants cautious interpretation rather than an unqualified claim of acceptable fit. Several methodological considerations are relevant here. First, RMSEA is known to be disproportionately sensitive to model misspecification in models with comparatively few degrees of freedom and modest sample sizes [41]; some elevation in RMSEA may be expected on statistical grounds alone given the present model’s degrees of freedom (df = 89) relative to its sample size (N = 140). Second, the χ²/df ratio (2.48) fell within the range considered acceptable for small-to-moderate samples [42]. Third, descriptively, the two-factor model showed better fit indices than the one-factor alternative across all reported indices; given the unverified estimator, formal Δχ² testing was not conducted. Taken together, we consider the two-factor model the most defensible structure for the present data, while explicitly noting that the marginal RMSEA and TLI indicate that this conclusion should be regarded as provisional pending replication in larger samples. The factor loadings for both EFA and CFA are presented in

Table 2. Exploratory and confirmatory factor analysis standardized loadings.

	EFA Factor Loadings		CFA Factor Loadings
Items	1	2	1	2
1. Gelecekte ne olacağını bilmemek benim için zor bir durumdur.	−0.176	0.850	-	0.679
2. Hayatta ne olacağını bilmemeye katlanamıyorum.	−0.128	0.966	-	0.830
3. Diğer çocuklar gelecekte ne olacağını bilmeme durumuyla başa çıkmakta benden daha iyiler.	0.331	0.267	0.548	-
4. Hayatta önceden bilemeyeceğim bazı şeylerin olmasına katlanamıyorum.	0.334	0.494	-	0.783
5. Başıma kötü bir şey gelme ihtimaliyle başa çıkmakta zorlanıyorum.	0.601	0.058	0.638	-
6. Önemli bir haber beklerken, sonucunu bilmemeyi kabullenmekte zorlanıyorum.	0.708	0.002	0.696	-
7. Emin olmadığım veya tahmin edilemez durumlarla uğraşmaya dayanamıyorum.	0.754	0.039	0.805	-
8. Ne olacağını bilmediğim bir durumda kalmaya dayanamıyorum.	0.704	0.165	0.855	-
9. Gelecekte ne olacağını bilmemekten nefret ediyorum.	−0.056	0.899	-	0.838
10. İlerde ne olacağını bilmediğim zaman beklemeye dayanamam.	0.278	0.596	-	0.835
11. Hayatta bilinmeyen veya kesin olmayan her şeyle başa çıkmakta zorlanıyorum.	0.580	0.272	0.797	-
12. Kötü bir şey olabileceğini düşündüğümde, bunun gerçekleşip gerçekleşmeyeceği konusunda kararsız kalmakta zorlanıyorum.	0.821	−0.104	0.702	-
13. Belirsizliktense her şeyi hemen bilmeyi tercih ederim.	0.286	0.404	-	0.659
14. Beklemediğim bir şeyin olabileceği düşüncesiyle baş etmekte zorlanırım.	0.596	0.235	0.781	-
15. Bir şeyi yapmayı kabul etmeden önce ondan emin olmam gerekir.	0.568	−0.180	0.399	-

Note. The highest factor loading for each item is shown in bold. EFA = Exploratory Factor Analysis; CFA = Confirmatory Factor Analysis.

. Regarding individual item performance, Item 15 (‘Before agreeing to do something, I need to be sure about it’) demonstrated the lowest factor loading in both EFA (λ = 0.568 on Factor 1) and CFA (λ = 0.399), and also displayed a negative cross-loading on Factor 2 (−0.180) in the EFA solution. These psychometric characteristics suggest that Item 15 may not function as strongly as other items within the Inhibitory IU subscale in this clinical adolescent sample, possibly because its wording reflects a relatively mild expression of uncertainty intolerance that may not adequately discriminate within a high-distress clinical population. Although Item 15 was retained to preserve the integrity of the original scale and maintain comparability with other validation studies, its performance should be re-examined in future studies, with particular attention to whether it contributes meaningfully to the inhibitory IU construct across different populations.

3.3. Convergent and Discriminant Validity

To assess the convergent validity of the scale, correlation coefficients with the Intolerance of Uncertainty Scale-12 (IUS-12), whose Turkish version was validated and reliability tested by Sarıçam, 2014 [29], were examined. Factor 1 (Inhibitory IU) showed a strong and significant correlation with the prospective anxiety subscale of the IUS-12 (r = 0.767, p < 0.001), the inhibitory anxiety subscale (r = 0.757, p < 0.001), and the total score (r = 0.818, p < 0.001). Similarly, Factor 2 (Prospective IU) demonstrated a strong and significant correlation with the prospective anxiety subscale (r = 0.825, p < 0.001), the inhibitory anxiety subscale (r = 0.727, p < 0.001), and the total score (r = 0.840, p < 0.001), supporting the scale’s convergent validity. To examine discriminant validity, correlation coefficients with the Parental Attitude Scale, whose psychometric properties were assessed by Yılmaz [31], were analyzed. Factor 1 was not significantly correlated with the acceptance/involvement and behavioral control subscales of the Parental Attitude Scale (p > 0.05), while it showed a weak but significant negative correlation with the psychological autonomy subscale (r = −0.194, p = 0.022). Similarly, Factor 2 was not significantly correlated with the acceptance/involvement and behavioral control subscales (p > 0.05) but was weakly and significantly negatively correlated with the psychological autonomy subscale (r = −0.217, p = 0.010). These results provide partial support for discriminant validity: IUI-A factors showed no significant correlations with two of three PAS subscales, consistent with expectations. However, the significant associations with the psychological autonomy subscale—albeit weak in magnitude—indicate that IU and perceived parental autonomy granting are not fully independent constructs in this sample. This partial overlap may reflect a developmentally meaningful relationship whereby lower perceived autonomy in family contexts amplifies adolescents’ sensitivity to uncertainty, rather than representing a measurement artifact. Accordingly, the discriminant validity claim should be considered provisional and interpreted with caution. These results are presented in

Table 3. Correlations among the IUI-A, IUS-12, and Parental Attitude Scale scores.

	M	SD	1	2	3	4	5	6	7	8	9
1. IUI-A Inhibitory IU	31.52	9.57	-
2. IUI-A Prospective IU	21.08	7.06	0.736 ***	-
3. Total scale score	52.60	15.64	0.948 ***	0.906 ***	-
4. IUS-12 Prospective IU	25.24	6.70	0.767 ***	0.825 ***	0.845 ***	-
5. IUS-12 Inhibitory IU	16.86	5.88	0.757 ***	0.727 ***	0.795 ***	0.734 ***	-
6. IUS-12 Total score	42.10	11.75	0.818 ***	0.840 ***	0.884 ***	0.936 ***	0.920 ***	-
7. PAS Acceptance/ Involvement	22.49	5.07	−0.024	−0.051	−0.040	−0.011	0.039	0.004	-
8. PAS Psychological Autonomy	20.41	5.64	−0.194 *	−0.217 *	−0.225 **	−0.181 *	−0.217 *	−0.211 *	0.218 *	-
9. PAS Behavioral control	25.16	4.77	0.148	0.153	0.166	0.173 *	0.245 **	0.214 *	0.149	−0.131	-

Note. * p < 0.05; ** p < 0.01; *** p < 0.001, IUI-A = Intolerance of Uncertainty Index-A, IUS = Intolerance of Uncertainty Scale (IUS-12), PAS = Parental Attitude Scale.

.

3.4. Known-Group Validity

To assess the known-groups construct validity of the scale, scores were compared between individuals with and without a lifetime history of suicide attempts based on the Columbia-Suicide Severity Rating Scale (C-SSRS). The SA group had significantly higher Factor 1 (Inhibitory IU) scores (Median = 35.00) compared to the SI group (Median = 28.50; U = 1301.00, p = 0.001, r_rb = 0.368) and significantly higher Factor 2 (Prospective IU) scores (Median = 24.00 vs. 19.50; U = 1397.00, p = 0.003, r_rb = 0.321). To examine whether these group differences remained significant after accounting for potential confounders, analysis of covariance (ANCOVA) was conducted for each IU subscale, with group (SA vs. SI) as the independent variable and gender, age, depressive disorder diagnosis, trauma exposure, and any anxiety disorder diagnosis as covariates. After controlling for all covariates, the group effect remained statistically significant for both Inhibitory IU (B = 5.64, SE = 1.70, t = 3.31, p = 0.001, 95% CI [2.27, 9.01]) and Prospective IU (B = 4.03, SE = 1.30, t = 3.10, p = 0.002, 95% CI [1.46, 6.61]). Notably, depressive disorder diagnosis was an independent significant predictor of Inhibitory IU beyond group status (B = 4.50, SE = 1.89, t = 2.38, p = 0.019). These findings indicate that the group differences in IU are not fully attributable to the measured confounders, providing additional support for the known-groups construct validity of the scale.

4. Discussion

The findings of this study provide preliminary support for the validity and reliability of the Turkish adaptation of the Intolerance of Uncertainty Index A (IUI-A) in a clinical adolescent population. The two-factor structure identified—Inhibitory IU and Prospective IU—aligns with prior conceptualizations of IU but also highlights important differences from previous IU measures. These findings suggest that intolerance of uncertainty in adolescents may manifest as both a difficulty in coping with uncertain situations (inhibitory IU) and an excessive concern about unpredictable future events (prospective IU).

Our results are consistent with prior research demonstrating the multidimensional nature of IU. Similar two-factor structures have been reported in other IU measures, such as the Intolerance of Uncertainty Scale-12 (IUS-12) [3] and the revised Intolerance of Uncertainty Scale (IUS-R) [27]. However, our study adds to the literature by examining this structure in a Turkish clinical adolescent sample, which had not been previously studied. The strong internal consistency of both factors (α = 0.891, ω = 0.897 for Inhibitory IU; α = 0.898, ω = 0.899 for Prospective IU) supports the reliability of the adapted scale, although, as discussed below, the confirmatory fit indices indicate that the factor structure should be interpreted with some caution.

One notable finding of our study is that IU was significantly associated with suicidal-behavior history. Adolescents with a history of suicide attempts scored higher on both Inhibitory IU and Prospective IU than those with suicidal ideation but no prior attempts. Importantly, these group differences remained statistically significant after controlling for gender, age, depressive disorder diagnosis, trauma exposure, and comorbid anxiety diagnoses in ANCOVA models, suggesting that the association between IU and suicide attempt history is not fully explained by the measured clinical and demographic confounders. These findings are consistent with prior research linking high IU to emotional dysregulation, avoidance behaviors, and maladaptive coping strategies that have been theorized to contribute to suicidal behaviors [4]. The known-groups validity results suggest that IU is associated with greater psychological distress among adolescents at elevated risk for suicide; however, given the cross-sectional design of the present study, these findings should be interpreted as evidence of association rather than as support for a causal or predictive role of IU in suicide risk. Longitudinal research is required to establish the temporal ordering of this relationship before causal or predictive claims can be made. Given that IU has been linked to impaired emotion regulation and heightened threat sensitivity in prior work [22], addressing IU in clinical interventions may represent a potentially valuable, though as yet unconfirmed, component of comprehensive suicide risk-reduction strategies [43].

Our findings are broadly consistent with earlier IU measures but also introduce some important distinctions. The original IUI-A [28] was designed to assess IU in children and adolescents, and our study largely parallels its psychometric approach in a Turkish sample, while extending it to a two-factor structure not explicitly delineated in the original validation. However, some studies using other IU measures, such as the IUS-12 and IUS-R, have found a more nuanced factor structure with additional subdimensions [44]. While our two-factor structure mirrors the distinction between inhibitory IU and prospective IU found in previous studies [3,12] further research is needed to determine whether additional facets of IU exist in Turkish adolescent populations.

The sociocultural characteristics of Turkish society are relevant to interpreting these findings. According to Hofstede’s framework [45], Turkey scores relatively high on uncertainty avoidance and collectivism, reflecting a culturally embedded tendency to minimize ambiguity through social norms and intergenerational interdependence. Cross-cultural evidence suggests that national uncertainty avoidance scores are associated with elevated anxiety in young adults [46]. However, the relationship between national-level cultural indices and individual-level IU is complex: Venaik and Brewer [47] demonstrated that Hofstede’s uncertainty avoidance index and the GLOBE model [48] capture distinct constructs, with high UAI scores potentially reflecting a cultural aspiration for certainty functioning as a compensatory response to socially disorganized environments rather than a direct index of individual IU. The present finding that lower perceived parental psychological autonomy was weakly but significantly associated with both IU subscales is consistent with theoretical accounts linking collectivist family dynamics to adolescent uncertainty sensitivity, and may also reflect specific mechanisms of parental interference in educational and career-related decision-making that have been linked to school anxiety, burnout, and depressive symptoms in adolescents [49,50]. Caution is warranted, however, in attributing observed findings primarily to cultural factors: sample characteristics, the translation process, statistical procedures, and the clinical composition of the sample represent equally plausible alternative explanations. Future cross-cultural research using matched samples and harmonized methodology is needed to clarify the role of cultural context in shaping IU expression and factor structure.

Our study was conducted in a clinical adolescent sample, which differs from many prior studies that examined IU in general populations. This distinction is important, as IU may be more pronounced in adolescents experiencing psychiatric distress, particularly those with suicidal thoughts and behaviors. Additionally, the sample consisted predominantly of female participants, which may have influenced the factor structure. Evidence regarding gender differences in IU remains mixed; while some studies report no significant differences between males and females [16,51] others suggest girls may show higher internalizing symptoms in the context of uncertainty [15]. Future studies should systematically explore gender as a moderator of IU factor structure in adolescent clinical samples.

Furthermore, the importance of validating IU measures in both clinical and non-clinical populations is highlighted by Erden & Çelik, 2024 [52] study, which examined the psychometric properties of the Intolerance of Uncertainty Scale for Children (IUSC) in a non-clinical Turkish sample of children aged 7–12. Their study confirmed a similar two-factor structure (Prospective IU and Inhibitory IU) and demonstrated strong internal consistency. This suggests that IU manifests similarly across clinical and community populations, though its intensity may vary. We note, however, that this is a comparison across different instruments and age ranges, and should not be read as direct evidence of measurement equivalence. The comparison between our study and Erden and Çelik [52] also raises questions about developmental differences in IU, as younger children and adolescents may process uncertainty in distinct ways. Future research should investigate how IU develops across different age groups and whether the same factor structure remains stable in broader samples.

Despite these contributions and the preliminary support provided for the psychometric properties of the Turkish IUI-A, the findings should be interpreted in the light of the limitations detailed above. Longitudinal research examining whether IU prospectively predicts suicidal behavior, alongside intervention studies testing whether IU-focused treatments reduce distress in high-risk adolescent populations, remains an important priority for future work.

In conclusion, the Turkish adaptation of the IUI-A shows preliminary evidence of reliability and validity as a measure of IU in adolescents, with the caveat that several aspects of the factor structure and psychometric properties—particularly model fit and cross-validation—warrant further investigation. The two-factor structure of the scale is broadly consistent with existing IU frameworks, supporting its potential utility in research and clinical settings, pending the additional validation work outlined above. Given the observed association between IU and suicidal-behavior history, this scale may eventually prove useful for early identification efforts aimed at reducing psychological distress in vulnerable youth, although this application should await confirmation from longitudinal and intervention research.

• Implications for Future Research and Clinical Practice: These findings have potential implications for research and clinical practice in child and adolescent mental health. The Turkish IUI-A may, pending further validation, serve as a useful clinical screening instrument for IU across a range of psychiatric presentations—including anxiety disorders, depression, and suicidal presentations—given the transdiagnostic nature of IU [6,7,8,10]. The IUI-A may be considered for research use and exploratory clinical assessment pending independent replication; routine clinical implementation should await validation in broader samples, establishment of test–retest reliability, and derivation of interpretive cut-off scores. In Turkish educational contexts, school psychological counselors may also consider IU as a relevant dimension for psychosocial monitoring during periods of high academic pressure; however, given that the present sample was entirely clinical, any school-based application should be regarded as exploratory and would require validation in non-clinical, school-based adolescent samples before implementation.
• Limitations and Future Directions: Several limitations of this study should be explicitly acknowledged. First, the same clinical sample was used for both exploratory and confirmatory factor analyses; without an independent cross-validation sample, the risk of capitalization on sample-specific variance cannot be excluded. Second, with N = 140, the sample is relatively small for CFA; while the χ²/df ratio and the improvement over the one-factor model support the chosen solution, the CFA results should not be regarded as definitive. Third, measurement invariance across relevant subgroups (gender, age group, diagnosis) was not examined, meaning that score comparisons across these groups cannot be assumed valid. Fourth, test–retest reliability was not assessed, and the temporal stability of the Turkish IUI-A remains unknown. Fifth, the CFA estimator was not documented; future studies should explicitly use WLSMV or other estimators appropriate for ordinal Likert data. Sixth, parallel analysis was not conducted for factor retention, which represents a methodological limitation relative to current best practice. Seventh, the sample was exclusively clinical (all participants presented with suicidal ideation or a history of attempts), meaning the factor structure may not generalize to non-clinical or community adolescent samples. Eighth, the sample was predominantly female (84.3%), which limits the generalizability of findings to male adolescents and prevents robust gender-based comparisons. Ninth, medication and treatment status at the time of assessment were not collected, representing a gap in clinical characterization. Tenth, the study does not provide clinical cut-off scores, diagnostic sensitivity or specificity values, or predictive validity estimates, and therefore cannot support individualized clinical decision-making in its current form. Eleventh, the cross-sectional design precludes conclusions about causal or temporal relationships between IU and suicidal behavior; longitudinal studies are needed to determine whether elevated IU precedes or merely co-occurs with suicidal presentations. Twelfth, the exploratory sensitivity ANCOVA analyses conducted to adjust for confounders (gender, age, depression, trauma, anxiety disorders) were not accompanied by formal evaluation of model assumptions (residual normality, homoscedasticity, homogeneity of regression slopes), and should therefore be interpreted with caution. Additionally, important covariates such as medication status and symptom severity indices could not be included due to missing clinical data. Finally, the principal psychometric validity measures (IUI-A, IUS-12, PAS) relied on adolescent self-report, which may be subject to response bias and shared-method variance; however, diagnostic classifications and suicidal-behavior group assignments were established using structured clinician-administered assessments (K-SADS-PL and C-SSRS), mitigating this concern for the clinical characterization of the sample.