Mental health antecedents of early midlife insomnia: evidence from a four-decade longitudinal study.

STUDY OBJECTIVES Insomnia is a highly prevalent condition that constitutes a major public health and economic burden. However, little is known about the developmental etiology of adulthood insomnia. DESIGN We examined whether indicators of psychological vulnerability across multiple developmental periods (psychiatric diagnoses in young adulthood and adolescence, childhood behavioral problems, and familial psychiatric history) predicted subsequent insomnia in adulthood. SETTING AND PARTICIPANTS We used data from the ongoing Dunedin Multidisciplinary Health and Development Study, a population-representative birth cohort study of 1,037 children in New Zealand who were followed prospectively from birth (1972-1973) through their fourth decade of life with a 95% retention rate. MEASUREMENTS Insomnia was diagnosed at age 38 according to DSM-IV criteria. Psychiatric diagnoses, behavioral problems, and family psychiatric histories were assessed between ages 5 and 38. RESULTS In cross-sectional analyses, insomnia was highly comorbid with multiple psychiatric disorders. After controlling for this concurrent comorbidity, our results showed that individuals who have family histories of depression or anxiety, and who manifest lifelong depression and anxiety beginning in childhood, are at uniquely high risk for age-38 insomnia. Other disorders did not predict adulthood insomnia. CONCLUSIONS The link between lifelong depression and anxiety symptoms and adulthood insomnia calls for further studies to clarify the neurophysiological systems or behavioral conditioning processes that may underlie this association.