Emerging Adults: A Cross-National Comparison of Adjusted and Maladjusted Population Groups at Age 25 in USA and Australia

Background. Emerging adulthood (18-25 years) is increasingly recognized as an independent developmental stage, with diverse educational, employment, relationship and parenting patterns. Individuals seek to resolve questions of identity, accept personal responsibility and manage autonomy and independence. Whilst most appear to navigate this stage well, some struggle. This period includes peak frequencies of mental health disorders and substance use. Prior analyses of young adult psychosocial adjustment in Victoria identified three psychosocial adjustment classes at age 21: (1) Adjusted (24.8%); (2) Normative (63.9%); and (3) Maladjusted (11.3%). This study identifies patterns of developmental progress at age 25 in two cohorts in Washington State USA and Victoria Australia, and predictors of healthy adjustment.

Methods. Data were drawn from the International Youth Development Survey (IYDS), a longitudinal study following representative youth samples from Washington State (N=961) and Victoria, Australia (N=984), commencing in 2002 at age 13 years. Data obtained in 2014/15 at age 25 years was analyzed (87% retention of baseline respondents). Latent profile analysis was used to define groups based on behaviour patterns, with indicators including measures of prosocial behaviour (civic awareness, engagement and volunteering) and socio-emotional dysregulation (tobacco, alcohol and substance use, sexual risk taking, mental distress and antisocial behaviours).

Results. In contrast to Hutchinson et al. (2016) who reported 3 classes, preliminary analysis found evidence for 2-class models for both Victorian and Washington State cohorts at age 25. For the Victorian cohort, the maladaptive class (36.4%), was more likely to have used tobacco and illicit drugs in the past year, to drink heavily, experience increased depressive symptoms and participate in antisocial behaviours, including theft and selling drugs. By contrast, the adjusted class (63.6%) was more likely to have engaged in volunteering, whilst other indicators of civic awareness and engagement did not differentiate between groups. Profiles for the Washington cohort showed a smaller maladaptive group (30.5%) who were likely to have had more sexual partners than the adjusted class (69.5%).

Discussion: The current analysis found strong support for a 2-class model differentiated by maladaptive behaviours, but weak evidence for differentiation based on positive adjustment. The finding of higher maladjustment in young adults in Victoria relative to Washington State can be understood in the context of higher levels of adolescent alcohol and drug use, previously documented in the IYDS. Further investigation will identify adolescent predictors and adult correlates of positive adult adjustment.