Dibenzepin hydrochloride is a new tricyclic antidepressant drug with pharmacological properties midway between those of imipramine and amitriptyline. In a double-blind comparative trial, J. M. Fielding (Med. J. Australia, 1969, 1, 614) found no significant difference in the speed of the effect of the two drugs in depressed patients. He reported that side-effects rated subjectively by patients were maximal before starting on the drugs and tended to decrease with time. The following trial was accordingly staged.