The neuropsychiatry of depression after brain injury.

Biological aspects of depression after brain injury, in particular traumatic brain injury (TBI) and stroke, are reviewed. Symptoms of depression after brain injury are found to be rather non-specific with no good evidence of a clear pattern distinguishing it from depression in those without brain injury. Nevertheless symptoms of disturbances of interest and concentration are particularly prevalent, and guilt is less evident. Variabilitiy of mood is characteristic. The prevalence of depression is similar after both stroke and TBI with the order of 20-40% affected at any point in time in the first year, and about 50% of people experience depression at some stage. There is no good evidence for areas of specific vulnerability in terms of lesion location, and early suggestions of a specific association with injury to the left hemisphere have not been confirmed. Insight appears to be related to depressed mood with studies of TBI indicating that greater insight over time post-injury may be associated with greater depression. We consider that this relationship may be due to depression appearing as people gain more awareness of their disability, but also suggest that changes in mood may result in altered awareness. The risk of suicide after TBI is reviewed. There appears to be about a three to fourfold increased risk of suicide after TBI, although much of this increased risk may be due to pre-injury factors in terms of the characteristics of people who suffer TBI. About 1% of people who have suffered TBI will commit suicide over a 15-year follow-up. Drug management of depression is reviewed. There is little specific evidence to guide the choice of antidepressant medication and most psychiatrists would start with a selective serotonin reuptake inhibitor (SSRI). It is important that the drug management of depression after brain injury is part of a full package of care that can address biological as well as psychosocial factors in management.