Early environment and major depression in young adults: A longitudinal study

Post-natal incubator care represents an early specific environment that may affect the risk for major depression later in life. A subsample of 1212 young adults from the French-speaking general population of the region of Quebec were selected from an ongoing longitudinal study that started during their kindergarten years. Information on peri-natal condition, obstetrical complications and incubator care was collected by consulting hospital medical records. Participants were evaluated using DSM III-R based psychiatric assessment when they were 15 and 21 years old. Incubator care predicted an approximate two- to three-fold decreased risk for depressive disorder at age 21. Results from three different logistic models adjusting for family adversity and for maternal depression confirmed this relationship. Analyses were replicated for depression at age 15, showing the same association in female adolescents. This study suggests that post-natal incubator care may paradoxically decrease the occurrence of major depression later in life. This protective effect might be direct (through optimized biological, physiological and sensory parameters) or indirect (induction of specific parent–child interactions due to the perception of their infant's vulnerability). This study could enhance understanding of the links between early post-natal environment and affective disorders later in life.