EA is a distinct period of human development that involves complex changes in neurobiological, psychological, and social systems. The instability provoked by these changes may trigger the onset or worsening of anxiety in vulnerable individu- als. Conversely, individuals with preexisting anxiety may struggle to navigate important developmental transitions during this life stage, leading to increased symptoms and associated impairment.
Neurobiological Development Human neurodevelopment continues throughout adolescence and EA, particularly in brain regions that support higher-order cogni- tive processes such as reasoning, planning, emotion regulation, and social cognition [7]. For example, cross-sectional studies show evidence of decreasing gray matter and increasing white matter in the frontal cortex between adolescence and EA [8, 9]. These changes likely reflect synaptic pruning and the myelination of axons in the frontal cortex; both of which support more efficient processing in this region [7]. In addition, these changes enable enhanced top-down control of limbic regions, which contributes to improved decision-making and emotion regulation capabilities dur- ing EA [7]. Maturation in the medial prefrontal cortex (mPFC) and inferior parietal lobule also leads to enhanced social cognitive abilities, such as improved perspec- tive taking [10]. Finally, adolescents and EAs show heightened mPFC activity in
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response to social cues compared to children, which coincides with an increase in self-conscious emotions during this life stage [11]. These neurodevelopmental changes likely enable EAs to navigate complex adult contexts, including work envi- ronments and romantic relationships.
However, these neurodevelopmental changes may set the stage for the onset of mental disorders, including anxiety disorders, in adolescents and EAs [7]. For example, limbic regions (e.g., amygdala and accumbens) mature in adolescence before prefrontal control regions, thereby creating a temporary imbalance in emo- tion regulation circuits [12–14]. This imbalance may trigger the onset of mental disorder (especially substance use and affective disorders) in adolescents with pre- existing risk [7, 12]. As the prefrontal cortex continues to develop in EA, top-down control of limbic regions increases and EAs become more adept at integrating infor- mation about future risks when making decisions [7]. Though typically adaptive, this increasing motivation to avoid situations with possible negative outcomes may also contribute to the onset of anxiety disorders [7]. Finally, enhanced perspective taking and self-conscious emotions in EA may precipitate or augment social anxiety symptoms, as social anxiety disorder (SAD) is associated with a heightened focus on the mental states of others [15].
Psychological Development
Emotion Regulation Emotion regulation abilities also mature during EA, supported by the neurodevelopmental changes described above. For example, EAs demonstrate increasing capacity to plan for the future and to consider the consequences of their actions when making decisions [16]. These abilities are necessary for EAs to achieve developmental milestones such as educational attainment and financial indepen- dence. EAs also demonstrate increasing competence in the use of emotion regulation skills. For example, research indicates that EAs are more likely to use adaptive emo- tion regulation strategies (e.g., social support seeking) compared to adolescents [17], and the use of reappraisal (an adaptive emotion regulation skill) increases between EA and older adulthood [18]. However, EAs also use negative emotion regulation strategies such as passivity and avoidance at rates comparable to adolescents [17].
Taken together, these findings suggest that EA is characterized by improvements in emotion regulation abilities, but that these skills continue to develop into adulthood.
EAs who struggle to hone these skills may be at risk for mental health problems. For example, researchers have observed that adaptive emotion regulation skill use pro- spectively predicts lower levels of anxiety and depression among EAs [19].
Identity EA is also a critical period for identity exploration and commitment. This stage is often characterized by limited parental oversight and responsibility and is therefore an ideal time for individuals to explore different identities in work, love, and worldview [2]. In addition, EAs may explore same-sex and/or other-sex behav-
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iors and adopt a sexual identity label during this life stage [20]. The process of identity exploration can be both exciting and stressful for EAs. For example, failure experiences in school, work, or romantic relationships may cause anxiety and worry in these domains [2], and sexual minority EAs may encounter discrimination and/or victimization that leads to distress [20]. Specific identity exploration processes, such as rumination about identity choices, have also been linked with psychopathol- ogy [21]. Finally, elevated levels of anxiety in EAs are associated with identity disturbance [22, 23] and difficulty in making identity commitments during this developmental stage. For example, in one study, EAs with high shyness and anxiety reported lower levels of identity commitment compared to their peers [24]. These studies suggest that anxiety may thwart identity development for EAs, particularly if avoidance limits their participation in specific life domains [24].
Social Development
Higher Education The majority of EAs in the USA (approximately 70%) enter some form of tertiary education after high school [25]. Higher education provides EAs with an opportunity to explore different identities and to build friendships with peers [25]. However, EAs also experience high levels of stress in college settings, which can have a negative effect on their mental health. For example, anxiety and depression symptoms have been shown to increase throughout the first year of col- lege [26]. Factors such as academic stress, disengagement from studies, and loneli- ness are all associated with psychological distress in college [27]. In addition, sleep disturbance and anxiety are reciprocally related in college students and can rein- force one another over time [28]. Thus, elements of the college environment (e.g., academic stress, social disconnection, sleep disruption) may lead to the onset or worsening of an anxiety disorder in vulnerable individuals.
Work and Unemployment Many EAs explore different jobs during this life stage, with the ultimate goal of selecting a long-term occupation [2]. Research indicates that uncertainty about this process is associated with negative psychosocial out- comes. For example, uncertainty about the future and worry about money/unem- ployment are reciprocally related over time among EAs [29]. These findings suggest that EAs who have difficulty tolerating uncertainty about the future may engage in excessive worry as a coping response, which over time could develop into an anxiety disorder such as generalized anxiety disorder (GAD). Unemployment during EA is also a risk factor for mental health problems. Specifically, experiences of work dis- ruption (i.e., being laid off, fired, or unemployed for an extended period) predict increasing depression symptoms among EAs [30]. Though the findings in this study were specific to depression and not anxiety, the stress associated with unemploy- ment in EA could also precipitate the onset or worsening of an anxiety disorder.
Social Relationships Finally, EAs must navigate significant change in their social relationships with family members and romantic partners. EAs typically engage in a
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process of separation-individuation from their parents and, in so doing, develop a sense of self that is distinct from their family of origin [31]. Ideally, this process does not sever the bonds between EAs and their parents, but allows the relationship to evolve and become characterized by increasing mutuality over time [31, 32].
Parenting style and other family variables impact the success of this transition. For example, EAs’ perceptions of parental support for their autonomy are associated with greater self-reported autonomy and social functioning during this life stage; and higher levels of autonomy and social functioning in EA are associated with lower anxiety and depression symptoms [33]. On the other hand, EAs who perceive their parents to be psychologically controlling report more problems with anxiety, depres- sion, and vocational identity [33, 34]. Thus parental support of EAs’ independence appears critical for fostering EAs’ psychological adjustment and preventing anxiety.
EAs must also navigate profound change in the domain of romantic relation- ships. By late adolescence, many individuals are developmentally capable of having close, intimate bonds [35]. However, the median age of first marriage in most high- income countries is typically not until age 30 [1]. EA is therefore characterized by considerable fluidity in romantic relationships [35]. Cohabitation without long-term commitment, transient relationships (e.g., hookups), and periods of being unat- tached are all common during this life stage [35]. Researchers have proposed that EAs tend to prioritize their own economic and professional goals and only commit to a long-term relationship once they are able to balance their aspirations with the needs of a partner [35]. EAs’ ability to navigate this transition appears predicated on strong interpersonal skills including insight, mutuality in relationships, and emotion regulation abilities [36]. EAs with weak skills in these areas report lower relation- ship satisfaction and higher levels of anxiety and depression [36].
In sum, EA is a life stage when individuals are separating from their families, but have yet to commit to a long-term romantic relationship. Many EAs therefore lack social support and are at risk for loneliness. Indeed, population prevalence data in Denmark [37], Australia [38], and the United Kingdom [39] indicate that EAs and the elderly are the age groups most affected by loneliness. Furthermore, a recent survey of 20,000 Americans demonstrated that the current cohort of EAs (i.e., Generation Z, those born from the mid-1990s to the mid-2000s) is the loneliest birth cohort in the USA [40]. The high prevalence of loneliness among EAs likely con- tributes to heightened vulnerability for mental health problems during this life stage (see [41, 42]). Furthermore, individuals with anxiety disorders in EA may struggle to establish and maintain high-quality relationships (see [43, 44]). In this way, lone- liness and anxiety symptoms in EA may reinforce one another over time.