Intra-familial dynamics of mental distress during the Covid-19 lockdown

Importance: Lockdowns and social restrictions imposed in response to the Covid-19 pandemic intensified the proximity and reciprocal exposure among members of nuclear families. It is unclear how variation in mental distress during this period is attributed to family members’ influence. Objective: Using genetic data from family members, it is possible to disentangle parent-driven, child-driven, and partner-driven influences of mental distress. We separated between two types of influences; direct genetic–how an individual’s genotype influences their own mental distress, and indirect genetic–how an individual’s genotype influence the mental distress of family members. Design, Setting and Participants: Based on a pre-registered analysis plan, we used longitudinal data from the Norwegian Mother, Father and Child Cohort Study, reported by adolescents (N=4,388), mothers (N=27,852) and fathers (N=25,953) during the first two months of the Covid-19 lockdown. Trio genome-wide complex trait analyses were used to separate direct and indirect genetic effects at each timepoint. Separate models also included adolescents’ non-pandemic responses (N=10,012). Trio polygenic score (PGS) design was used to investigate direct and indirect effects of specific liability factors, and whether the associations changed over days in lockdown, adding interaction terms (PGS×time). Exposure: Family trios’ genotype and PGS for anxiety, depression, ADHD, neuroticism, and anorexia nervosa. Main Outcome: Mental distress was measured using the five-item version of the Hopkins Symptom Checklist. Results: We found evidence of family members influencing each other, with a pattern of greater proportions of variance explained later in lockdown. Indirect genetic effects were observed across family members; 10% of the variance in adolescent mental distress was mother-driven, 2-3% in mothers were partner-driven, and 5% in fathers were offspring-driven. Mothers’ genetic liability to depression and ADHD was positively associated with fathers’ mental distress. No interaction effects between PGS and time were found. Direct genetic effects contributed to 9-10% variance in mental distress across family members, partly explained by genetic variants associated with anxiety, depression, ADHD, and neuroticism. Conclusions and Relevance: These findings highlight the importance of family dynamics, particularly during societal crises like the Covid-19 pandemic and emphasizes the value of including family members in mental health interventions.