Stroke survivors given antidepressant therapy appear to gain long-term benefits in executive cognitive function that are independent of drug effects against depression, according to an article in the March issue of the British Journal of Psychiatry.

Antidepressant treatment already was known to improve mood in depressed stroke patients, but such therapy had not been examined in terms of effects on executive function in people with clinically diagnosed stroke, said Sergio Paradiso, MD, PhD, the study's corresponding author and assistant professor of psychiatry at the University of Iowa Carver College of Medicine.

Paradiso noted that cognitive effects were noted after patients had received a 12-week course of antidepressant therapy. People with stroke often show impairments in executive function and may not be able to respond well to non-routine situations. This impairment may affect rehabilitation efforts.

The study enrolled 47 patients who had had a stroke during the previous six months and randomized them to take fluoxetine, nortriptyline, or a placebo. Executive functions were assessed using standard neuropsychological tasks at the end of 12 weeks of treatment, and again two years after the study had started. A total of 36 patients completed all evaluations.

No significant differences were found between the antidepressant and placebo groups at the end of treatment. However, 21 months after treatment ended, the placebo group showed continued worsening of executive functions, whereas the antidepressant group had clear and significant improvement regardless of the status of depressive symptoms.

"We were somewhat surprised to initially not find any difference after the first 12 weeks of treatment. It took another 21 months after the initial treatments for the antidepressants to have a detectable effect," Paradiso said.

The investigators hypothesize that antidepressants may foster recovery of neural tissue not directly destroyed by the stroke, yet because the process is slow, it takes months.

"We can do functional and structural brain imaging studies using different technologies, including relatively new techniques that quantify chemicals in the brain," Paradiso said.