Comparison between acute- and delayed-onset depression following traumatic brain injury.

Sixty-six patients admitted for the treatment of acute closed head injury were assessed for the presence of mood disorders during the in-hospital period and at 3-, 6-, and 12-month follow-ups. Diagnosis was made using a structured psychiatric interview and DSM-III criteria. A total of 28 patients had major depression at some time during the study: 17 had acute-onset depression and 11 had delayed-onset depression. Acute-onset depressions are related to lesion location and may have their etiology in biological responses of the injured brain, whereas delayed depressions may be mediated by psychosocial factors, suggesting psychological reaction as a possible mechanism.