SummaryBackgroundPopulation-based longitudinal studies on bereaved children and youth's mental health care use are scarce and few have assessed the role of surviving parents' mental health status.MethodsUsing register data of individuals born in Sweden in 1992–1999, we performed a matched cohort study (n = 117,518) on the association between parental death and subsequent initiation of antidepressant treatment among individuals bereaved at ages 7–24 years. We used flexible parametric survival models to estimate the hazard ratios (HRs) over time after bereavement, adjusting for individual and parental factors. We further examined if the association varied by age at loss, sex, parental sociodemographic factors, cause of death, and the surviving parents' psychiatric care.FindingsThe bereaved were more likely to initiate antidepressants treatment than the nonbereaved matched individuals during follow-up (incidence rate per 1000 person years 27.5 [26.5–28.5] vs. 18.2 [17.9–18.6]). The HRs peaked in the first year after bereavement and remained higher than the nonbereaved individuals until the end of the follow-up. The average HR over the 12 years of follow-up was 1.48 (95% confidence interval [1.39–1.58]) for father's death and 1.33 [1.22–1.46] for mother's death. The HRs were particularly high when the surviving parents received psychiatric care before bereavement (2.11 [1.89–2.56] for father's death; 2.14 [1.79–2.56] for mother's death) or treated for anxiety or depression after bereavement (1.80 [1.67–1.94]; 1.82 [1.59–2.07]).InterpretationThe risk of initiating antidepressant treatment was the highest in the first year after parental death and remained elevated over the next decade. The risk was particularly high among individuals with surviving parents affected by psychiatric morbidity.FundingThe10.13039/501100004359Swedish Research Council.