Suicide Interventions in Spain and Japan: A Comparative Systematic Review

(1) Background: This systematic review presents an overview of psychological interventions in suicide published between 2013 and 2023 in Spain and Japan, sparked by Spain’s alarming recent increase in suicide rates and the potential exemplar of Japan’s reduction efforts. (2) Methods: Following the PRISMA checklist, the databases Web of Science, Scopus, PubMed, and PsycInfo were searched using the terms [(“suicide” OR “suicidal behavior” OR “suicidal attempt” OR “suicidal thought” OR “suicidal intention”) AND (“prevention” OR “intervention” OR “psychosocial treatment” OR “Dialectical Behavior Therapy” OR “Cognitive Therapy” OR “psychotherap*”)] AND [(“Spain” OR “Spanish”) OR (“Japan” OR “Japanese”)]. We included articles published in peer-reviewed academic journals, written in English, Spanish, and Japanese between 2013 and 2023 that presented, designed, implemented, or assessed psychological interventions focused on suicidal behavior. (3) Results: 46 studies were included, concerning prevention, treatment, and training interventions. The risk of bias was low in both Spanish and Japanese studies, despite the lack of randomization of the samples. We identified common characteristics, such as psychoeducation and coping skills. Assertive case management was only highlighted in Japan, making an emphasis on active patient involvement in his/her care plan. (4) Conclusions: The findings will help professionals to incorporate into their interventions broader, more comprehensive approaches to consider more interpersonal components.


Introduction
Suicide continues to be the main cause of unnatural death in Spain.Despite how, historically, Spain has had the lowest suicide rates in Europe, in recent years this trend changed, increasingly alarmingly, reaching in the year 2022 its highest suicide rate of 4227 people.Among the highest risk groups, men between 30 and 39 years old stand out as well as youngsters between 15 and 29 years old.The most recent data to date in Spain, for the first half of 2023, show 1967 deaths (75.2% men and 24.8% women) [1].
Although suicide has been a topic of growing interest in recent years, in Spain there is still no national plan for its prevention, despite the need expressed by health professionals [2].An example of a country that does have a strategy for its prevention at the national level is Japan [3].Although it is not the only one that has it, there are also countries within the European Union such as Norway [4] or Finland [5]; Japan also has a long 2 of 31 trajectory in the study of this phenomenon, also due to its high incidence [6].However, Japan managed to reduce its suicide rate to historical values a year before COVID-19, with a total of 20,169 deaths in 2019.That decline began in 2012, with total suicide rates of 21.60, but despite this it increased again after the incidence of the pandemic, especially among youngsters (479 teens in 2020) [7].The suicide-incidence data in Japan show a slight rebound (21,881 people in 2022), reaching values similar to those of 2016 with 21,897 people, although it is not as high as many years ago [8].Last year, in 2023, it decreased by 63 from the previous year (21,818) [9].It still impacts, as usual, the male sex, due to factors such as unemployment, which made this population more vulnerable, since a relationship was seen between unemployment and suicide rates [10], and despite COVID-19's impact, it was more severe in the daily life of women [8].
From a psychological approach, interventions are defined here as those focused on suicide risk assessment, clinical treatments, and professional training in suicide-related practices [11].A study that described the elements of interventions for suicide prevention plans across various regions in Spain showed that approximately 82% of them incorporated enhancements in early detection, assessment, prevention, and intervention for situations involving the risk of suicide.Regarding training interventions, there were found to be awareness-raising measures, guidance, and training workshops for effectively addressing the topic of suicide in the media and training specifically designed for professionals in sectors like education.It should be noted that the Valencian Community stood out as the sole region that specified a time frame within its objectives, considering that not all communities had a suicide-prevention program [12].
This highlights a need for consideration of the critical elements in suicide intervention and for identifying countries with extensive experience in addressing this issue, which could offer valuable guidance for our endeavors.In the inaugural nationwide analysis aimed at assessing the effectiveness of a national Japanese suicide-prevention strategy in various regions, including Japan and other countries, the study investigated the influence of the national fund in establishing frameworks and executing the nine proposed initiatives for suicide prevention.The findings determined that funding support at the national level for the implementation of suicide-prevention measures at the local level was an important factor, so that these could be put into operation, adapting them to the needs of the population and their capacity for implementation [3].The introduction of a national suicideprevention policy prompted a rise in the adoption of Gatekeeper Training (GKT) programs in Japan, indicating that the policy announcement resulted in favorable developments in the implementation of these programs that represent a fundamental element within suicide-prevention strategies in this country [13] In addition to intervention programs in any of their modalities in Japan, the importance of educating about the issue of suicide has also been studied.Kodaka et al. [14] investigated the existing status of incorporating suicide education into undergraduate social-work programs in Japan.The study focused on examining the perspectives and apprehensions of educators.Over 80% of the survey participants expressed consensus on the importance of integrating suicide education into the academic curriculum for Clinical Social Work (CSW) and Psychiatric Social Work (PSW) students.Additionally, around 70% of those responsible for teaching CSW or PSW courses expressed a desire to incorporate topics related to suicide in their classes.
The government of Japan outlined objectives to reduce the suicide mortality rate, including enhanced support for practical initiatives at the local level (prefectures and municipalities), strengthening prevention measures for youth suicide, since it represents a particularly vulnerable population, and addressing suicide linked to work-related issues [15].In different regions of Japan, innovative initiatives have underscored the significance of community-centric approaches to prevent suicide and intervene with high-risk individuals [16].
Therefore, given the high prevalence of suicide rates in Japan, its culture and attitudes toward this issue, its well-developed and innovative healthcare resources that create a sup-portive environment for the implementation and assessment of different suicide-prevention interventions and strategies, and its ongoing social and economic changes, which facilitate comparative research, we considered Japan a relevant and appropriate country for conducting a comparative study on suicide.
The aim of this study was to make a comparative review of what is published in scientific databases about the characteristics of psychological interventions directed to suicidal behavior or with an effect on it, designed for the Spanish and Japanese population with a scientific basis.Psychological intervention includes processes like health promotion, prevention, and treatment applying psychological principles and techniques by a health professional.Secondly, the aim was to find points in common and significant differences so that it serves to mutually apply in both countries to factors that may not have been considered and can benefit from their implementation.
Our research questions (RQs) were the following: -RQ1.What kind of elements were included in the interventions in each country?-RQ2.What prevention elements were included in Japan, but not in Spain?
Specifically, we aim to do the following: -Identify and analyze the specific elements included in suicide interventions implemented in Japan and Spain; -Compare and contrast the suicide-prevention elements that were part of the interventions in Japan and that were not present in the interventions in Spain; -Identify successful or innovative practices that could be adapted or implemented in the Spanish context in order to be an example to follow for improving suicideprevention strategies.
Focusing on the period of 2013-2023 and covering almost the beginning of the decline of Japan's high suicide rates, we offer a critical vision of the psychological approach to this problem, bringing to light aspects that may have been ignored in both countries and that may have been key to the intervention, thus benefiting them reciprocally from these findings, although always with a certain margin of variability, considering cultural differences.

Information Databases and Searches
The PRISMA verification protocol was used [17] for the development of reviews for both countries.A literature search was conducted in the electronic databases PsycInfo, Web of Science, and Scopus due to their specialized coverage in the field (PsycInfo), multidisciplinary scope (Web of Science, Scopus), and advanced search and citation analysis features, facilitating systematic reviews.We used the following terms: [("suicide" OR "suicidal behavior" OR "suicidal attempt" OR "suicidal thought" OR "suicidal intention") AND ("prevention" OR "intervention" OR "psychosocial treatment" OR "Dialectical Behavior Therapy" OR "Cognitive Therapy" OR "psychotherap*")] AND [("Spain" OR "Spanish") OR ("Japan" OR "Japanese")].The search covered articles from 2013 to 2023 written in Spanish, English, or Japanese, and was made on 9 June 2023 on PsycInfo, Web of Science, and Scopus, and then on 20 August 2023, adding the databases PsycArticles and PubMed.Finally, the search in PsycArticles was eliminated since the results were much fewer than in the other databases and did not provide documents different from those already found in these.
In relation to the search strategy, we carefully selected keywords related to suicide, including various aspects such as suicidal thoughts, so that it gave a wide range of results, as well as terms associated with prevention and intervention strategies.The use of the Boolean operators "AND" and "OR" allowed us to obtain a structured and focused search query.By using "AND", we ensured a refined search of the literature specifically addressing suicide interventions.Meanwhile, "OR" broadened the search to include synonyms and related concepts.
Our choice of search terms may not encompass every possible aspect of suicideprevention interventions, and there was a possibility of omitting relevant studies due to variations in terminology or indexing practices, although we endeavored to include a diverse range of keywords to mitigate this limitation.

Data Collection
A search using Mendeley Desktop was made two times, in May and in September of 2023, for this comparative review, and then the screening of the documents.Mendeley Desktop allowed for reference management, collaboration between authors, and integration with word processors.The lead author of this review, N.L.M.-R., made the initial search independently, so the references of the documents were extracted from the databases.The title and abstract screening of all papers was independently performed by two of the authors (M.d.P.M.C. and N.L.M.-R.) with reference to the inclusion/exclusion criteria.Those articles that in their title included the word review/meta-analysis, non-suicidal self-injury, names of populations or countries other than Spain and Japan, and interventions focused on treating suicide grief were discarded.Then, reading the abstract, we could remove articles that tried to validate tests, models, or psychological theories, as well as those that included non-psychological interventions.There were two disputed studies that seemed to be the follow-ups of other studies included in the final sample.This was resolved through discussion between two authors (M.d.P.M.C. and N.L.M.-R.).After full-text reading, we were able to compare the metadata of the studies to clarify the presence of articles that could be the progression of others, such as the article with the follow-up results of another study in the group of Spanish articles, and another independent in the Japanese intervention group.Finally, using tables, the characteristics of interest of the articles (main objectives, samples, aspects addressed, places of action, duration, components of the interventions, and their phases) were revised for all the authors.

Assessment of Risk of Bias and Reporting Quality
In addition to conducting a thorough search, four members of the group (N.L.M.-R., M.d.P.M.C., Y.K., and B.D.) independently reviewed the full-text screening process and its outcomes.In instances of disagreement, we collaboratively revisited the items in question, aiming to identify specific features that could warrant their exclusion or inclusion.Through this joint effort, we reached a consensus that determined the final selection of items.As for the articles written in Japanese, the member of the group originally from this country, Y.K., carried out a more exhaustive review of these.
To assess the risk of bias in the gathered studies, we dissected and presented the interventions' characteristics, considering some relevant criteria on the detailed reporting of manuscripts: (a) criteria for patient inclusion; (b) the control or comparison group; (c) treatment descriptions; (d) characteristics of the sample; (e) data on outcomes; and (f) the inclusion of lost-to-follow-up patients.The first author, N.L.M.-R., coded each item as either met or not met (including cases where it was not clear) for each document.After this, the second author, M.d.P.M.C., supervised this process.
The assessment process in evaluating the risk of bias was structured around key components, through a tailored approach aligning with established criteria outlined in tools such as Cochrane Collaboration's Risk of Bias Tool [18] for randomized controlled trials or the Newcastle-Ottawa scale [19] for non-randomized studies.
Since the focus of analyzing the studies was to compare the common characteristics of interventions conducted in both countries and their outcomes, , a narrative synthesis of the findings was used.In this way, we tried to identify and analyze specific elements included in suicide interventions in Japan and Spain, such as types of interventions and prevention elements; to compare elements in Japanese interventions absent in Spanish interventions; and to identify successful or innovative practices from Japan for adaptation in Spain, considering implementation methods, demographic characteristics, and contextual factors.

Study Selection
Articles were included if they (a) presented, designed, implemented, or assessed psychological intervention programs focused on suicidal behavior, or whether the intervention, although not primarily directed at suicidal behavior, influenced this; (b) the interventions were designed for or applied to the Spanish or Japanese population; (c) or they were published in a peer-reviewed academic journal, written in English.Articles were excluded if (a) the study was a review or meta-analysis, (b) the study tried to validate tests, models, or psychological theories, (c) they were focused on populations other than the Spanish or Japanese, or they were addressed to ethnic minorities living in other countries, (d) they were other formats different from the scientific article, or (e) they included interventions in modalities other than psychological.
There were no restrictions on the design of the studies since this was also an evaluable aspect.
The period between 2013 and 2023 was chosen since 2012 was the turning point from which a decline in suicide rates was seen in Japan, although recent years were also considered despite a new rise in ratios as a result of the COVID-19 pandemic to give a broader and more current overview of the problem.

Data Analysis
Given the variability in interventions focused on the problem of suicide or risk variables related to it, what was sought were not numerical values, but rather the analysis of the qualitative characteristics of these interventions, as well as the results of their effectiveness.To address this objective, we conducted a content analysis to consolidate and synthesize the results following the Braun and Clarke's six steps [20].Microsoft tools such as Word and Excel were used for manually organizing and analyzing textual data extracted from included studies.The process began with an initial review of key concepts in titles and abstracts to filter relevant articles (terms derived from suicide or psychological interventions were applied for this problem).After familiarizing ourselves with the data, we found the following themes: training programs, prevention, and treatment interventions.After that, we identified initial codes (intervention components) for articles related to our interest in interventions affecting suicidal behavior.Extracting relevant information from selected articles involved a specific search for key themes and subtopics, followed by a deeper review to determine refinements.Ultimately, we adjusted and clarified potential themes and subthemes to address our research questions investigating the initial framework from the introduction of the studies and the results observed both in the short and long term.The subtopics included aspects on which it intervenes and the framework or approach with which it is applied.

Results
The initial bibliographic search yielded a total of 1430 outcomes including the terms "Spain" or "Spanish", compared to 1258 outcomes including the terms "Japan" or "Japanese".Following the removal of duplicates, 883 articles were chosen in the Spanish search and 629 in the Japanese.Abstracts were then examined to identify studies for inclusion, and findings were extracted from the complete texts.After applying inclusion and exclusion criteria and scrutinizing the title and abstract of each study, 23 studies were ultimately included in each review, making a total of 46 articles examined.Figures 1 and 2

Methodological Quality Analysis
The analysis based on the criteria already presented showed that not all the interventions had a control group to compare their effects.A proportion of 4/23 in the Spanish sample [21][22][23][24] and 5/23 in the Japanese sample [25][26][27][28][29] included a control group exempt from treatment, although some had a group that received a different treatment, with a

Methodological Quality Analysis
The analysis based on the criteria already presented showed that not all the interventions had a control group to compare their effects.A proportion of 4/23 in the Spanish sample [21][22][23][24] and 5/23 in the Japanese sample [25][26][27][28][29] included a control group exempt from treatment, although some had a group that received a different treatment, with a proportion of 5/23 in the Spanish sample [30][31][32][33][34] and 3/23 in the Japanese sample [35][36][37].While, in the Japanese sample, two articles [38,39] included the relatives of the patient, in the Spanish sample we found two articles [24,40].
All the interventions, both in Spanish and Japanese samples, included a description of the treatments and data on outcomes.Regarding the inclusion of lost-to-follow-up patients, all the Spanish articles included this, except that of Espandian et al. [41], since it is focused on effective strategies in a specific pandemic context, Marco et al. [40], because it is a randomized control trial, and Reijas et al. [33], due to its retrospective nature.And, in the Japanese sample, we found more articles without lost-to-follow-up participants [26,28,35,42,43].In both samples, most studies were non-randomized for the convenience of accessible patient groups, except for four studies in the Spanish sample [24,34,44,45] and eight in the Japanese sample [37,38,[46][47][48][49][50][51].Finally, as to the characteristics of the samples of the articles, they are explained in detail in the following section.

Sample Characteristics
The samples size of the Spanish articles varied widely, from 30 to 12,596 participants, and was the same in the Japanese sample, ranging from 19 to 631,133 participants.
Regarding gender, there is a prevalent trend where, despite the inclusion of both genders in the samples, the proportion of women is noticeably greater than that of men.This aligns with the existing literature indicating that women exhibit a higher attempt rate than men, despite men being more prominently represented in completed suicides.Regarding the interventions, there are various interventions including those cognitive, cognitive-behavioral, supportive counselling, dialectical behavior therapy, educational interventions, and humanistic therapies.We observed a greater number of case interventions, although the sample number of the articles was high, more than community or group interventions, in both groups of articles (Spanish 4/23 and Japanese 7/23).Although, there may be some that combine individual treatment with group treatment [24,34,35].

Study Characteristics
With regard to the components of the interventions, in both samples the following can be seen: psychoeducation about anxiety, depression, and suicide; practical training (role play); coping/problem-solving strategies; emotional regulation strategies; mindfulness; cognitive restructuration; behavior activation; relaxation techniques; visual information through videos or written messages; anxiety-control strategies; mentalization exercises; and the validation and humanization of the collective experience.But the Japanese sample differs in the inclusion of discussion groups, assertive case management, and gatekeeper training.
With respect to the time duration of the interventions, in the Spanish sample, we found shorter interventions focused on treatment once the problem had already appeared, lasting a few hours/weeks.However, longer interventions ranging from months to years were more focused on preventing damage.In the Japanese sample, we found longer interventions in treatment, , and brief training interventions of a few hours, even though these are more numerous in this sample.In interventions aimed at prevention, we found more variability in proportion, from brief interventions of a couple of hours (3/11) to longer ones over months (4/11) or years (4/11).

Training Programs for Other Professional or Non-Professional People in Its Detection and/or Treatment
In the Japanese sample, we observed many articles of this type, nine, compared to the Spanish sample with only one article about a training intervention.The age of the sample of the Spanish training program is not specified, but on the Japanese interventions, three are focused on young adults and the rest on middle adults.Regarding the sites where they were carried out, three were on educational institutions, three on clinical settings, two were carried out online, and one in a local government.

Health Promotion and Suicide-Prevention Interventions
In the Spanish sample, we found a total of 11 suicide-prevention interventions, similar to the Japanese sample with 10.Of the 11 Spanish interventions, 4 were focused on adolescents, and the rest were adults with a mean age around 40 years.Compared to the Japanese sample, where we found more variety in targeted age ranges, three interventions were focused on minors, three on young adults (between 22 and 32 years old), one on middle-aged adults, one on elderly people, and three included people of very different age ranges, from teenagers to older adults.
Most of the Spanish interventions were designed and/or developed for clinical/medical settings, except one of them that was outpatient [52] and another that took a double route, online-telephone [53].On the other hand, in the Japanese sample, four of the interventions took place in clinical settings, three in educational institutions, one online, one promoted by the local government, and another in a residential care setting.

Treatment of Suicidal Behavior Interventions
Eleven of the total Spanish sample of articles were about the treatment of this problem, although there were actually 10 interventions, since two of the articles evaluated the effectiveness of the same treatment in the short and long term, a significant amount compared to the Japanese sample, with 4 interventions.Most of the Spanish interventions were focused on adults, and the samples that included minors also included older age ranges, so they did not focus on youngsters specifically.The Japanese interventions were focused on young people older than or equal to 20 years.
In the Spanish sample, like prevention interventions, most of these were designed and/or developed for clinical/medical settings, except two that were outpatient [22,54] and one in a residential setting [55].Regarding the Japanese interventions, a total of four interventions were developed in clinical settings.
Tables 1 and 2 describe the main features of the selected articles with the terms Spain or Spanish, and Japan or Japanese, correspondingly.The research method was a questionnaire survey (suicide-prevention questionnaire forms), completed after the training session.
The involvement of lifestyle-support counsellors increased.
To examine the feasibility and effects of online gatekeeping.
139 consultation service users, mean age 23.8 years old.
To promote help seeking in those using web search services. Online.
Between July and December 2013.Not specified.
Using Google AdWords, keyword-targeted advertisements for a website, and using suicide-related keywords.
The advertisements were linked to the website, encouraging the use of an e-mail consultation service.An e-mail address for consultations and phrases to encourage viewers to use such services.Home visits, intervention (psychoeducation, collaboration with family members to create support, commitment to not getting hurt, and support in problem solving, risks, and benefits about psychotropics), and follow-up.
Suggests effectiveness for reducing suicidal ideation and improving maternal mental health.

In person. No
A more detailed analysis of the effectiveness-proven Spanish and Japanese interventions is shown in Table 3.

Outcomes Notable Aspects
Angora et al.
(2022) [30] Assessment not included in the data-collection protocol for this research.
Percentage reduction and delay of suicide attempts.
Reinforcement of common treatment, providing flexible service tailored to the individual circumstances.
Cebrià et al. ( 2013) [56] Through an interview and considering days elapsed between the first suicide attempt and the percentages.
Time elapsed between initial suicide attempt and subsequent and short-term effects on suicide rates.
Reinforcement of the in-person intervention with the telephone is essential.Detection of a risk factor for suicide in adolescents.
Effective results but limited to the study design.

Harada et al. (2019) [26]
In-person interviews, Japanese version of the BIS/BAS scale, items related to counselling behavior, observation.
Acquisition of emotional and communication abilities.
Inclusion of emotional education and consultation skills in educational environments where the suicidal risk may still be low.
Increase in skills and self-perception of effectiveness in its implementation.
A program focused on teachers rather than students.
Increased capacity to manage cases of suicidal behavior among students.
Compensates for the lack of closeness in university environments.

Outcomes Notable Aspects
Inui-Yukawa et al.
Reduced incidence and prevalence of suicide.
It emphasizes early intervention, involving collaboration with community resources.
Impact on attitudes towards suicide, skills, and self-efficacy in the application of measures for its prevention.
Inclusion of assertive case management within formal training.
Improved intervention skills and self-confidence in suicide prevention.
Enrichment of the virtual environment (case studies and role-playing) to allow a gatekeeper prevention program at a distance.

Nakagami et al. (2018) [64]
Ten yes-or-no questions to evaluate knowledge, six questions on a five-point Likert scale for confidence, and original questionnaires for skills.
Increasement of mental health knowledge, confidence, and skills to prevent suicide.
Considerable effects in a short time intervention focusing on depression and suicidal behavior.

Japanese interventions
Norimoto et al.
(2020) [48] Incidence proportion of the first episode of recurrent suicidal behavior.
Assertive case management was significantly effective for the Axis I group.
Delivering psychoeducational content and information about social resources before.Oyama and Sakashita (2017) [28] Observation of suicide rates.
Probably lower suicide rates.
Detection of cases of depression with a predisposition for suicidal behavior.

Oyama and
Sakashita (2016) [65] Difference in changes in suicide rates and number of deaths from national registry data.
Long-lasting effects reducing suicide rates.
Importance of depression screening for suicide prevention.
Reduction levels of anxiety and depression that predispose people to suicidal behavior.

Prioritizing cognitive behavioral techniques
Sakamoto et al.
Increase in knowledge about suicide.
Brief exclusive use of digital media (video) as prevention measure.
Increased protective factors against suicide, specifically social support.
Community involvement in problems that affect peers.
Increased use of help resources.
A passive procedure from professionals through new technologies to achieve adherence to treatment.To summarize, among the main communalities in the Spanish and Japanese interventions focused on prevention or treatment, we highlight a component of psychoeducation, even it is brief [40,51], coping skills [26,30], the promotion of adherence to treatment [38,62], and key concepts about anxiety and/or depression [37,53], but we can also find this component of psychoeducation about depression in training interventions, like Hashimoto et al. [63] in the Japanese sample.We find some peculiarities in Spanish interventions strategies, like validating and humanizing the collective experience [53].As for the differences, these are more evident in the training programs; the Japanese interventions offer more specific and complete information about suicide, such as warning signs of suicide and risk factors [25], and the Spanish one includes more general strategies, like interpersonal skills or communication-skills training [40].

Discussion
This systematic review aimed to identify suicide-prevention interventions in Japan and Spain and compare them.From 2688 articles (1258 in Japan and 1430 in Spain) retrieved, 46 papers (23 in Japan and 23 in Spain) were included.The studies examined in this current review delve into the provision of information and counselling for academic and clinical settings to improve or implement measures regarding the problem of suicide.The objective is to compare the most recent published interventions in both countries, recognizing underlying problems and factors influencing that behavior, as well as possible effective strategies against suicide, encouraging their involvement in this problem.There are notable differences among the studies in terms of intervention types and the evaluation of measured variables.This divergence complicates the comparison of outcomes.Although, an important strength in this review was the variety of the methodological frameworks of the included studies, such as quasi-experimental studies or observational studies, since this offers valuable insights, being cautious in their interpretation and able to mitigate potential confounding factors to ensure robust findings.
About the feasibility of the interventions, most of them were feasible to implement, and focusing on the records of follow-ups, they were able to retain participants possibly due to the use of stable contexts, such as clinical settings or educational institutions.
As for key similarities and differences between Japanese and Spanish interventions studied, we can verify the following: Similarities: -

Intervention Types
Consistent with the literature about suicide, which advocates for prevention rather than postvention [12,70,71], we mostly found, in both countries, that interventions aimed at prevention and the training of professionals to carry it out on vulnerable populations (e.g., young people and hospital patients), allowing them not only to preserve their health in environments that are also habitual for them, but also to involve those responsible on many occasions for the well-being of these population groups in these controlled environments.Stable contexts allowed for collaborative partnerships, a greater control of participants, and facilitated long-term follow-ups, thus increasing the chances of success for interventions.
Answering the research questions, regarding the kind of components that were included in the interventions in Spain and Japan, we can mention those that included psychoeducation about the problem, gatekeepers, techniques to improve communication (assertiveness, help-seeking and role play), and coping strategies and techniques for managing anxiety and depression, like relaxation exercises or behavioral activation.Specifically, among the innovative effective elements included in the Japanese interventions that have not been found in those implemented in the Spanish interventions, we should highlight such a direct approach when the medium used is remote (e.g., online with encouragement messages), when leadership has involvement with messages to the community and the promotion of social support networks between them, and the use of assertive case management.The involvement of leaders is essential, as we can see that public campaigns on this topic already found good results before in Japan, implemented in specific areas [72].To some extent, these results are consistent with studies that support these types of strategies in suicide intervention [73][74][75].
As we can see in this review, prevention strategies utilizing emerging technologies were used in interventions in recent years, especially in the Japanese sample, although research in this area remains limited [76].The effective utilization of technology in suicide prevention still presents a significant challenge [77], teaching both patients and healthcare professionals to use it.
At an economic level, we know the impacts these changes can have on suicidal behavior and even more so in Japan, being more sensitive than social factors [78].It should be noted that the three interventions that considered the COVID-19 situation and/or were developed after this event [41,53,55] within the Spanish sample were focused on prevention, which already denoted a growing interest in treating this problem, possibly aggravated by the crisis caused by the pandemic.In the Japanese sample, only one intervention included COVID and focused on treatment [25].From the start of the COVID-19 pandemic in 2020, we did not find more published interventions for suicide compared to the rest of the years.In view of our results, we cannot consider 2020 a year from which COVID will take on great relevance in the publication of interventions for this problem, perhaps considering these last years as a stable phase in the implementation of interventions for this problem, since we found other articles after this year that do not mention it.This fact fits with the data about a decline in suicide rates during the early months of the pandemic in Japan [79,80], although the negative effects may not have been evident so early, since later, the COVID-19 pandemic showed a negative impact on suicide rates in Japan, especially in women and youngsters [81].
Despite the challenges posed by external factors such as the COVID-19 pandemic, individuals and communities developed resilience and coping mechanisms that influenced the effectiveness of suicide interventions.Given that many of the interventions became remote, new ways were sought to create connection despite the lack of non-verbal information, and the provision of interactive material through technology seemed to help adherence, in addition to the flexibility and security that these means offered.

Cultural Considerations
Although eastern-Japanese culture prioritizes stable interdependence, this is in contrast with western cultures, like Spain, that emphasize individual independence and maintaining familial ties [82].Social support was a variable that was highly taken into account in the interventions aimed at both the Japanese and Spanish populations, either including their relatives in the intervention or facilitating contact with them while they were being treated, as poor social support is a very important variable that predicts suicide attempts, especially between youngsters [83].
Socio-cultural differences between Spain and Japan, including attitudes towards suicide, interpersonal needs, disclosure practices, and personal values, should be explored to understand their impact on suicide rates and intervention effectiveness.By contextualizing these factors, researchers can develop interventions tailored to each population's unique needs.Examining their norms, beliefs, cultural values related to individualism vs. collectivism, and attitudes towards suicide, we will be able to predict the acceptability and efficacy of intervention strategies in each country.

Limitations
On the one hand, ensuring that published articles meet certain standards of quality and reliability, we were limited to scientific databases for research purposes, and we did not consider public documents from central and local governments and the grey literature [84].By focusing on articles published in these journals, our systematic review was more likely to include studies that had undergone thorough scrutiny by experts in the field, in addition to its greater power of impact and dissemination outside the origin country.
On the other hand, there were psychological-intervention programs that were combined with other treatments in another modality, for example, pharmacological, which made it difficult to discern what degree of effectiveness was attributed to the psychological program.We also did not evaluate what parts of the interventions were effective [76].Finally, a limitation that comes from the sample used in some interventions refers to its size or its origin, since, for example, with very small or non-randomized samples, it is difficult to make a generalization.

Conclusions
Overall, similarities between Spanish and Japanese interventions focused on prevention or treatment included elements such as psychoeducation, coping skills, or the promotion of treatment adherence.However, Spanish interventions emphasized interpersonal aspects, while Japanese interventions are more specific and comprehensive to the issue.
Regarding the characteristics of the interventions, we could highlight the shorter duration of those carried out in Spain, focusing on immediate treatment, while Japanese interventions span longer terms, cover bigger groups, and comprises more varied age ranges.
These differences underscore the need for tailored suicide-prevention policies in both countries.Spain may benefit from incorporating broader, comprehensive approaches akin to those in Japan, while Japan could consider integrating more interpersonal components into its interventions.Additionally, the longer duration and broader age inclusivity of Japanese interventions suggest a more comprehensive strategy for suicide prevention, offering valuable insights for shaping policy decisions to reduce suicide rates in both Spain and Japan.
It is important to carry out this type of comparative work so that the position of the countries of interest in terms of mental health problems can be seen Suicide is a problem that affects developed and developing countries to a greater extent.Therefore, countries like Spain that do not have a National Strategic Plan for Suicide Prevention can take the example of countries like Japan that do, and have been very well received, despite the stigma of this problem.It also shows that, despite the cultural differences that may exist between countries such as Spain and Japan, there are common aspects that can be useful in both countries.
Although Japan would not be the only country that has had a long history with this problem and significantly reduced its suicide rate, it does share with Spain a growing concern about the rise among youngsters.The OECD presented Japan as one of the countries with the highest suicide rates among under-30s [85].
In addition to the importance that cross-cultural studies have, applied to test psychological models and theories in different cultures, they are also very useful for studying cultural and psychological variations that may or may not be present in our own cultural experiences.In the context of cultural adaptation, if we wanted to incorporate in Spanish intervention elements that have been effective in the other country and vice versa, research should explore the integration of cultural elements and understanding into treatment approaches, since significant differences can be found in models of training and service structures, and also, of course, elements that can be effective in one society, given the values, lifestyles, and education, which do not have to coincide with those of another.
Despite the existence of cross-cultural studies that explore the different perspectives in addressing different problems [86], there are no studies that focus specifically on comparing the different interventions developed in both countries in such an exhaustive way.
We believe in the importance of this kind of research, especially influencing the policies in the prevention and treatment of suicide in both countries, as it serves as an example of mutual learning.
In summary, comparative studies, even when they are between two specific countries, like Japan and Spain, can provide valuable information that other countries can use to develop more effective suicide-prevention strategies, identifying risk and protective factors that possibly go ignored, improving mental health services' analyses of disparities in their accessibility and quality, and addressing the specific needs of different cultural groups within their populations (attitudes toward suicide, mental health, and help seeking).

Future Directions
Cultural factors like the perceptions of suicidal Spanish population groups have could be found between the implications for policy development, as well as the feasibility and effectiveness of community-based suicide-prevention initiatives.
Longitudinal studies will continue to give us clues about what the future objectives are and how the population needs are changing, while ensuring certainty about those aspects that remain effective over time.
It is necessary to continue learning and taking examples from other countries that have already found themselves in similar critical situations, while taking into account cultural differences and adapting them to the target population.It is expected that these types of comparisons encourage governments to implement a national suicide-prevention plan that is in high demand, since prevention is much more important than postvention.
Globally, suicide has become an alarming threat to society.All healthcare practitioners have a responsibility to disseminate awareness and information among the population about the measures that can be taken for its prevention.Strategies more focused on suicidalbehavior information were most frequently addressed in the studies carried out in Japan and more interpersonal approaches in Spain.This attempt could help societies to be aware of the clinical characteristics that are most relevant in this approach.
display the PRISMA Flow Diagram, illustrating the process of article selection made for both countries.
display the PRISMA Flow Diagram, illustrating the process of article selection made for both countries.

Figure 1 .
Figure 1.Flowchart of the selection process of the articles of review with the terms Spain or Spanish, following PRISMA.Figure 1. Flowchart of the selection process of the articles of review with the terms Spain or Spanish, following PRISMA.

Figure 1 .
Figure 1.Flowchart of the selection process of the articles of review with the terms Spain or Spanish, following PRISMA.Figure 1. Flowchart of the selection process of the articles of review with the terms Spain or Spanish, following PRISMA.

Figure 2 .
Figure 2. Flowchart of the selection process of the articles of review with the terms Japan or Japanese, following PRISMA.

Figure 2 .
Figure 2. Flowchart of the selection process of the articles of review with the terms Japan or Japanese, following PRISMA.
Eligible studies were published between 2013 and 2022 with a median = 2019 on the Spanish sample and median = 2017 on the Japanese sample.The interventions described in the studies included the following: (1) face to face and telephone contacts, (2) telephone consultations, (3) telephone follow-ups, (4) smartphone-basedI interventions, (5) group interventions, and (6) other technology-based interventions.Very brief interventions were found in both samples, from a 2 h training session to months exceeding a year in duration.

Table 1 .
Main characteristics of the interventions in the Spanish population.

Table 2 .
Main characteristics of the interventions in the Japanese population.