Timing of Exposure to Parental Depression From Pregnancy to Young Adulthood and Mental Health in Adult Offspring.

Importance: Exposure to parental depression is a risk factor for offspring mental illness. Objective: To examine the association between the timing of exposure to parental depression, from pregnancy to young adulthood, and adult offspring mental health. Design, Setting, and Participants: This prospective longitudinal cohort study of adult offspring aged 22 to 27 years in the Avon Longitudinal Study of Parents and Children, a British birth cohort, was conducted from September 1990 to July 2020. Data were analyzed from March 2024 to January 2026. Exposures: Parental depressive symptoms were assessed repeatedly using the Edinburgh Postnatal Depression Scale (score range, 0 to 30, with higher scores indicating more severe depressive symptoms) beginning in pregnancy through offspring age of 21 years. Main Outcomes and Measures: The main outcomes were offspring symptoms of depression at age 27 years, anxiety at age 25 years, psychotic disorders at age 24 years, and alcohol use disorder (AUD) at age 22 years. Covariates included socioeconomic status and maternal-offspring polygenic risk for multiple psychiatric disorders. Results: A total of 5329 adult offspring (3276 females [61.5%]) provided at least 1 outcome measure, which included 3795 participants providing symptoms of depression (mean [SD] age, 27.8 [0.5] years), 3505 participants providing symptoms of anxiety (mean [SD] age, 25.3 [0.6] years), 3342 participants with assessments for psychotic disorders (mean [SD] age, 24.5 [0.8] years), and 3392 participants reporting on symptoms of AUD (mean [SD] age, 22.9 [0.5] years). Cumulative exposure to parental depression across all time points was associated with increased odds of offspring depression (maternal: AOR, 2.36 [95% CI, 1.91-2.92]; paternal: AOR, 2.13 [95% CI, 1.60-2.83]) and anxiety (maternal: AOR, 2.58 [95% CI, 2.06-3.23]; paternal: AOR, 1.98 [95% CI, 1.49-2.63]). Only maternal depression was associated with increased odds of psychosis symptoms (maternal: AOR, 1.90 [95% CI, 1.27-2.82]; paternal: AOR, 1.63 [95% CI, 0.95-2.80]). There were no statistically significant associations with AUD. Significant associations between maternal depression and adult offspring depression were observed from 32 weeks' gestation (AOR, 1.08 [95% CI, 1.01-1.15]) to age 18 years (AOR, 1.08 [95% CI, 1.01-1.16]). Maternal depression from the 8-month postnatal period (AOR, 1.06 [95% CI, 1.01-1.11]) onward (aged 21 years: AOR, 1.13 [95% CI, 1.02-1.24]) was associated with offspring anxiety symptoms. Paternal depression was significantly associated with offspring depression from mid-childhood (AOR, 1.08 [95% CI, 1.01-1.15]) onward (aged 21 years: AOR, 1.22 [95% CI, 1.04-1.43]), with similar associations between paternal depression and offspring anxiety from mid-childhood (aged 5 years: AOR, 1.11 [95% CI, 1.03-1.18]) onward (aged 21 years: AOR, 1.22 [95% CI, 1.04-1.43]). Only maternal prenatal depression at 32 weeks' gestation was associated with offspring psychotic symptoms (AOR, 1.20 [95% CI, 1.03-1.41]). Conclusions and Relevance: In this cohort study, analyses of 2 decades of data found distinct temporal associations between maternal and paternal depression and offspring psychiatric symptoms, and pregnancy was found to be a sensitive period in the association between maternal depression and offspring psychotic experiences. The findings suggest a substantial role of timing for specifying the association between parental depression and psychiatric outcomes in young adults and emphasize the need to support parental mental health from pregnancy onward.