Remission from depression is delayed in adults who have experienced childhood physical abuse or parental addictions, a new study by University of Toronto researchers has found. The study is published this week in the journal Social Psychiatry and Psychiatric Epidemiology.

University of Toronto investigators examined a range of factors associated with remission in a sample of 1,128 depressed Canadian adults, drawn from the National Population Health Survey. Depressed individuals were followed every other year until remission occurred, for up to 12 years. "Our findings indicated that most people bounce back. In fact, three-quarters of individuals were no longer depressed after two years," reported co-author and Professor Emeriti Tahany M. Gadalla. However, not everyone recovered at the same rate.

"Early adversities have far-reaching consequences. The average time to recovery from depression was 9 months longer for adults who had been physically abused during their childhood and about 5 months longer for those whose parents had addiction problems" says lead author Esme Fuller-Thomson, Sandra Rotman Endowed Chair in the University of Toronto's Factor-Inwentash Faculty of Social Work.

"Numerous studies have shown that childhood abuse and parental addictions make individuals more vulnerable to depression," says co-author and MSW graduate Marla Battiston. "Our research highlights that these factors also slow the recovery time among those who become depressed."

Although this study could not determine why childhood adversities are associated with poor depression outcomes, the researchers speculate that negative experiences may interrupt the normal development of the hypothalamic-pituitary-adrenal (HPA) axis, which affects stress regulation. "In many studies, adult depression has been characterized by HPA axis hyperactivity," says co-author and recent PhD graduate, Sarah Brennenstuhl. "This link is an important avenue for future research."