Treatment of aggression and irritability After head injury. 
Kant, R., Smith-Seemiller, L., & Zeiler, D. (1998). Brain Injury, 12, 661-666.

This article focused upon the problems associated with aggression, impulsivity, and other personality and behavioral changes following closed head injury (CHI). In fact, the authors noted that family members report these issues to be more distressing than other consequences of brain injury (e.g., memory problems). Other researchers have found relationships between decreased serotonin neurotransmission and violent, aggressive, and impulsive behaviors in a wide variety of patient populations, with some successful outcomes following the use of serotonergic agents.

This particular article described the outcome of a small, non-blind 8 week pilot study of sertraline (also known as Zoloft) in the treatment of irritability and aggression following CHI. The study participants were outpatients with a history of mild to severe CHI who did not have a current substance use disorder or a diagnosis of either delirium or dementia. They were administered two questionnaires that measured aggression, irritability, suicidality, and depression. Participants initially took 50 mg. of of Zoloft per day, which was eventually increased to the maximum dose of 200 mg. per day, dependent upon each participant's response (e.g., some subjects did not require the maximum dose to report positive effects).

Results of this study showed that most of the participants experienced a clinically significant decline in aggressive and irritable behavior, a change which was still evident after 8 weeks. Perhaps most importantly, family members reported similar changes after only one week of treatment. This finding is significant, as it gives more credence to changes being accounted for by decreases in aggression and irritability, and not necessarily depressive symptoms, as Zoloft usually takes at least 3-4 weeks before improvement is noticed.

While these findings seem promising, they must be viewed with caution, due to the small sample size, lack of blind ratings, and absence of a control group. However, results are overall very important, as they point to the need for future studies that investigate the effects of Zoloft on aggressive and irritable behavior with such studies carefully addressing the aforementioned weaknesses of the present study. In addition, the authors noted that objective rating scales completed by both participants and family members were of great utility, and in future studies of this kind, they should be used in combination with self-report measures.

Jennifer McCain, Psy.D. 
Neuropsychologist, 
The Brady Institute for Traumatic Brain Injury and Coma Recovery