The aim of this study was to evaluate platelet 3H imipramine binding in suicide attempters as compared with depressed patients, & healthy controls. Aggressive features in the 3 groups were also studied. The results showed a significant decrease in the maximum binding capacity of 3H-imipramine binding to platelet membranes in suicide attempters, who also exhibited higher total & single item scores on aggression measures. Findings suggest an aggression dysregulation in suicide attempters.