Mediators of age differences in well-being and psychological distress across adulthood

Objectives Aging is associated with improvements in well-being and reductions in psychological distress. However, little is known about why this occurs. This study explored candidate psychological variables that may explain age differences in mental health.Methods We used cross-sectional data of 5712 Canadians aged 18–101 to explore associations between age and mental health, and then to investigate whether basic psychological needs (BPNs), loneliness, perceived control, mindfulness, optimism, and neuroticism mediated age’s relationship with well-being and distress.Results Each variable in this study predicted age differences in mental health. We also found evidence that different mediators accounted for age differences in distress and well-being. For well-being, BPN fulfillment was the strongest mediator (β = 0.158, 95% CI [0.142, 0.175], 49.5% of total effect), followed by optimism (β = 0.064, 95% CI [0.055, 0.073], 20.1% of total effect), loneliness, perceived control, and neuroticism. For psychological distress, loneliness was the strongest mediator (β = −0.086, 95% CI [−0.097, −0.075], 17.8% of total effect), followed by neuroticism (β = −0.078, 95% CI [−0.088, −0.068], 16.2% of total effect), BPN fulfillment, mindfulness, optimism, and perceived control.Conclusion Our findings support the dual continuum of mental health with age and point to variables that may explain why older adults have greater well-being (e.g., because they have greater BPN fulfilment) and less distress (e.g., because they are less lonely). These variables are potential targets of intervention for those older adults whose mental health does not improve with age, as well as for younger adults whose mental health was poorer, on average.