Depression, anxiety and eating disorders (“social-emotional disorders”) are common during adolescence and emerging adulthood (i.e., 10–30 years of age) (Gibb et al., 2010
; Kessler et al., 2012
). Ongoing identity development may increase vulnerability to social-emotional disorders, whilst such difficulties may also impede identity development (Klimstra & Denissen, 2017
). Increased understanding of any link between identity development and social-emotional disorders may help to improve prevention and intervention efforts for these difficulties. However, intervention development remains in its infancy, and rigorous reviews which synthesize existing basic research are needed to advance the field. This study aims to narratively synthesize and meta-analyze the findings of longitudinal studies which have examined prospective associations between identity synthesis and confusion and symptoms of social-emotional disorders during adolescence and emerging adulthood.
Large prospective cohort studies indicate that 40 to 50% of adolescents and emerging adults meet diagnostic criteria for a mental disorder (Gibb et al., 2010
; Kessler et al., 2012
). Many more young people experience subthreshold symptoms, which can cause distress and impairment and lead to later clinical need (Van Oort et al., 2009
). Epidemiological studies indicate that depressive, anxiety and eating disorders are particularly widespread during adolescence and emerging adulthood (Galambos et al., 2006
; McLaughlin & King, 2015
; Van Oort et al., 2009
). Researchers have noted phenotypic similarities between depressive, anxiety and eating disorders (e.g., heightened emotionality and social sensitivity), and suggested that these disorders might be conceptualized collectively as “social-emotional disorders”, and may share etiological and maintenance factors (Rapee et al., 2019
Developmental psychopathologists suggest that understanding normative adolescent and emerging adult development can provide valuable insights into the mechanisms that eventuate in or maintain social-emotional disorders during these life-stages (Cicchetti & Rogosch, 2002
). Self-identity formation is one such normative developmental process for adolescents and emerging adults (Schwartz et al., 2013
). During these life-stages, young people seek answers to questions related to who they are and who they would like to be in different life domains (e.g., vocation; relationships; religious beliefs; values) (Schwartz et al., 2013
). Whilst several more recent theories of identity development (e.g., narrative identity; McAdams, 2011
) have been proposed, Erik Erikson’s seminal theory remains the dominant theoretical framework (Schwartz et al., 2013
). It proposes that successful identity development involves moving from a state of predominant “identity confusion” (i.e., a sense of inconsistency or uncertainty in one’s idea of oneself) towards “identity synthesis” (i.e., a sense of sameness and continuity of the self; Erikson, 1950
). “Exploration” (i.e., trying various identity options) and “commitment” (i.e., selecting identity options) were later proposed as the key processes underpinning identity confusion and synthesis (Marcia, 1966
). Based on levels of past and current exploration and commitment, individuals can be categorized into four discrete identity statuses: “diffusion”; “moratorium”; “foreclosure” and “achievement” (Marcia, 1966
). Subsequent neo-Eriksonian models retain a focus on the interplay between synthesis and confusion, with variations in how exploration and commitment are conceptualized (Crocetti et al., 2008
; Luyckx et al., 2008a
) (see Table 1
for summary of these processes). Several questionnaires have been developed to measure these processes (e.g., Dimensions of Identity Development Scale (DIDS); Utrecht Management of Identity Commitments Scale (UMICS); Crocetti et al., 2010
; Luyckx et al., 2008a
Summary of identity confusion and synthesis-related concepts
Committing to a set of identities
Identification with commitment
Embracing one’s identity commitments and integrating them into the sense of self
Exploration in depth
Exploring existing identity commitments
Reconsideration of commitment
Comparing existing identity commitments to other possible options
Exploration in breadth
Exploring identity options prior to commitment
Ruminating over identity options
There has been longstanding interest in the connection between mental health and identity synthesis/confusion during adolescence and emerging adulthood (Klimstra & Denissen, 2017
). A number of longitudinal and cross-sectional studies have identified that identity confusion is positively correlated with depressive and anxiety disorder symptoms (Crocetti et al., 2011
; Luyckx et al., 2015
; Luyckx et al., 2013a
; Luyckx et al., 2008a
; Marcotte and Levesque, 2018
; Sica et al., 2014
). Researchers have suggested that the relationship between identity confusion/synthesis and social-emotional disorders may operate in a similar way to the relationship between personality traits (e.g., perfectionism, neuroticism) and depression and anxiety symptoms. Several hypotheses have been outlined (see Table 2
for a summary); in essence, identity development difficulties may increase the likelihood of the emergence of social-emotional disorders, social-emotional disorders may increase the likelihood of identity development difficulties, or both phenomena may be underpinned by common causes (Klimstra & Denissen, 2017
Putative hypotheses regarding the relationship between identity synthesis/confusion and social-emotional disorders (based on Klimstra & Denissen, 2017
Identity development difficulties (e.g., high identity confusion/low identity synthesis) and social-emotional disorders have common causes
High identity confusion/low identity synthesis and social-emotional disorders form a continuous spectrum
High identity confusion/low identity synthesis are precursors of social-emotional disorders
High identity confusion/low identity synthesis predispose to developing social-emotional disorders
High identity confusion/low identity synthesis have patho-plastic effects on social-emotional disorders
High identity confusion/low identity synthesis are state-dependent concomitants of social-emotional disorders
High identity confusion/low identity synthesis are consequences of social-emotional disorders
Increased understanding of any link between identity synthesis and confusion and social-emotional disorders in young people may help to improve prevention and intervention efforts for these difficulties. Indeed, some identity-focused interventions do already exist. For example, the Miami Identity Development Project is a peer-led intervention aims to promote identity synthesis through in-depth exploration and working through identity-related distress (Meca et al., 2014
). However, intervention development remains in its infancy, and rigorous reviews which synthesize existing basic research are needed to advance the field.
Social-emotional disorders are common during adolescence/emerging adulthood, times of intense identity development. Increased understanding of any link between identity development and social-emotional disorders in young people may help to improve prevention and intervention efforts for these difficulties, yet few reviews synthesize existing basic research exploring this relationship. This study aimed to narratively synthesize and meta-analyze the findings of longitudinal studies which have examined prospective associations between identity synthesis and confusion and symptoms of social-emotional disorders during adolescence and emerging adulthood.
The narrative synthesis found partial support for the hypotheses of this review. Several studies found evidence for an overlap between identity development and depression and anxiety symptoms, such that adolescents and emerging adults in identity development trajectories characterized by high synthesis and low confusion had fewer depression and anxiety symptoms than those in identity development trajectories characterized by low synthesis and high confusion (Becht et al., 2016
; Crocetti et al., 2009
; Hatano et al., 2020
; Luyckx et al., 2008b
; Meeus et al., 2012
; Nelemans et al., 2014
There was some evidence that depression, anxiety and eating disorder symptoms impact identity development, such that elevated symptoms were associated with identity development difficulties (i.e., low identity synthesis/high identity confusion) later in adolescence (Hatano et al., 2020
; Schwartz et al., 2012
; van Doeselaar et al., 2018
; Verschueren et al., 2018
; Verschueren et al., 2021
). Preliminary evidence indicated that effects may differ according to identity domain (i.e., depressive symptoms associated with later educational synthesis, but not interpersonal synthesis) (van Doeselaar et al., 2018
Evidence regarding effects in the opposite direction (i.e., impact of identity development on later depression and anxiety symptoms) was mixed. Some studies indicated that difficulties with identity development were associated with more depressive symptoms later in adolescence, but others found no effect (Becht et al., 2019
; Hatano et al., 2020
; Hatano et al., 2018
; Meca et al., 2017
; Schwartz et al., 2012
; Schwartz et al., 2011
; Schwartz et al., 2017
The narrative review therefore found some support for bidirectional relationships between identity confusion/synthesis and social-emotional disorders i.e., that high identity confusion and low identity synthesis are both a cause and a consequence of social-emotional disorders. However, it is important to note that many studies did not control for identity development/social-emotional disorder at baseline so it is difficult to be certain about the direction of the effect. Furthermore, it is possible that both identity confusion and social-emotional disorders can be explained by a common factor not assessed or controlled for within these studies. Indeed, both social-emotional disorder and identity development difficulties might be better explained by other normative developmental processes (e.g., cognitive development, attachment).
The meta-analyses did not support the hypotheses of this review. Contrary to expectation, there was no significant change in identity confusion over time and a meta-regression was therefore not conducted. Visual inspection of the forest plot suggests that two studies - by the same research group, and drawing participants from the same cohort - found effects in the opposite direction to the other studies (i.e., increasing identity confusion), driving this counter-intuitive finding (Hatano et al., 2019
; Hatano et al., 2020
). The most apparent difference between these studies and the others is that participants were young people in Japan; it may be that cross-cultural differences in identity development could explain the disparity in findings. The meta-analyses did find a decrease in anxiety and depression over adolescence/emerging adulthood, but this decrease was not significantly predicted by the identity variables (baseline and change in identity synthesis and confusion). Likewise, identity synthesis increased over adolescence/emerging adulthood, but such change was not significantly predicted by either change in depression and anxiety symptoms or baseline depression.
There was therefore a discrepancy between the findings of the narrative synthesis and that of the meta-analyses. As the meta-analyses included a sub-sample of the studies included in the narrative synthesis, differences in included and excluded studies may explain these disparate findings. However, included and excluded studies appear broadly similar in terms of age-group, quality rating and other extracted characteristics. It is also possible that, as only nine studies were included in the meta-analyses, the meta-regressions may not have been sufficiently powered to detect an effect (Higgins et al., 2019
This study’s findings must be interpreted in light of some limitations. Gray literature and non-English studies were excluded from the review. Whilst previous studies have highlighted that non-English and gray literature studies represent only a very small percentage of the total studies included in reviews and are associated with negligible change in results (Hartling et al., 2017
), it is possible that potentially informative studies were not identified which may bias the findings. Studies were predominantly conducted in the Netherlands and the United States, which may limit the generalizability of the review’s findings. There are likely to be differences between these countries and other countries regarding identity development and its association with mental health. Furthermore, most of the studies included in this review were only of fair quality. Studies demonstrated shortfalls in selection and comparability of study groups (e.g., nonrepresentative samples; relevant factors not controlled for at baseline) and measurement of outcomes (e.g., self-report questionnaires; <70% retention rates). Finally, the meta-analyses were also subject to some limitations. It was not possible to include all identified studies in the meta-analyses due to heterogeneity of sample design. Additionally, the meta-analyses included multiple publications drawing on participants from the same cohort. It is possible that this may bias the estimates of effect size.
Directions for Future Research
The present review highlights several gaps in the existing evidence base, which might be usefully addressed in future research. Future studies should aim to address the quality deficits of existing research, for instance by recruiting representative samples, controlling for relevant factors, and maximizing participant retention across follow-up phases. As identified, most existing research has focused on depression and anxiety. Whilst these types of difficulties are of obvious relevance to adolescent and emerging adult populations, it important to also investigate other disorders (e.g., eating disorders) that are also prevalent and are associated with significant impairment amongst young people. Additionally, all studies included in this review adopted a dimensional approach to depression, anxiety and eating disorders. Future studies might usefully also assess identity development in young people who meet criteria for clinical diagnoses, a more rigorous test of clinically meaningful symptom change.
Most existing research has been conducted in adolescents, yet it is likely that associations between identity development and depression, anxiety and eating disorders symptoms vary according to age. Indeed, previous cross-sectional research has highlighted age graded associations between identity process and mental health problems (e.g., Luyckx et al., 2013a
; Luyckx et al., 2008a
). Further research should focus on elucidating prospective associations between identity development and social-emotional disorders amongst emerging adults, whilst ideally including age-based comparison groups.
Most of the studies included in this systematic review examined non-domain-specific identity development, or interpersonal and educational domains. There is growing evidence that young people who belong to sexual orientation minorities and with gender identity concerns face significant mental health challenges, yet there is an evident lack of studies researching how development of sexual and gender identity is related to mental health. Furthermore, few of the studies assessed other factors that may influence associations between identity development and depression, anxiety and eating disorders. Many factors, both proximal and distal, are likely to influence this relationship (e.g., family, school and peer context; childhood trauma; genetic influences) (Klimstra & Denissen, 2017
; Rapee et al., 2019
). Future studies should take more careful account of this.
Social-emotional disorders are common during adolescence/emerging adulthood, yet few reviews synthesize existing research on the relationship between these disorders and ongoing identity development. This review identified 20 studies which examined longitudinal associations between identity development and social-emotional disorders in adolescents and emerging adults. The narrative synthesis found some evidence for bidirectional relationships between identity synthesis and confusion and socio-emotional disorders during adolescence and emerging adulthood. Meta-analyses of a sub-sample of these studies found no significant relationships between depression and anxiety symptoms and identity synthesis and confusion. This review highlights issues with the quality of research within the field, with all included studies only of fair or poor quality. There were shortfalls in selection and comparability of study groups (e.g., nonrepresentative samples; relevant factors not controlled for at baseline) and measurement of outcomes (e.g., self-report questionnaires; <70% retention rates). Further research should aim to address these shortfalls, so that clear conclusions might be drawn, and clinical recommendations made.
RP, KA and US designed the review; RP and AA jointly conducted the systematic searches and completed data extraction; LR conducted the meta-analyses and meta-regressions; RP wrote the manuscript, with critical revisions from US, KA, AA, LR and HW. All authors read and approved the final manuscript prior to submission.
RP and LR are funded by the National Institute for Health Research (NIHR) Biomedical Research Center (BRC) for Mental Health, South London and Maudsley NHS Foundation Trust (SLaM) and Institute of Psychiatry, Psychology and Neuroscience, King’s College London (KCL). AA is funded by a KCL International Postgraduate Research Scholarship. HW is funded by the NIHR Evaluation, Trials and Studies Coordinating Center (NETSCC) (project reference 17/123/03). KA received support from the NHS Innovation Accelerator program in 2017-2018. US is supported by an NIHR Senior Investigator Award. This paper represents independent research funded by the NIHR BRC, SLaM and KCL. The views expressed are those of the authors and not necessarily those of the NIHR or the Department of Health and Social Care. The funders had no role in study design, data collection or analysis, decision to publish, or preparation of the manuscript.
Data Sharing and Declaration
The datasets generated and analyzed during the current study are not publicly available but are available from the corresponding author on reasonable request.
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