AGE-SEX DIFFERENCES IN RESPONSE TO ANTIDEPRESSANT DRUGS

Abstract

Age-sex differences were examined in two multihospital collaborative studies of drug treatment in depression. The 325 patients in study 1 and 555 patients in study 2 were subdivided into four age-sex groups: females under 40; females 40 and over; males under 40; and males 40 and over. The major focus of the statistical analyses was on differential treatment effects in the four age-sex groups. The treatments in study 1 were chlorpromazine (600 mg/day), imipramine (300 mg/day), or a placebo. Study 2 patients received diazepam (30 mg/day), phenelzine (45 mg/day), or a placebo. Results after 3 weeks of treatment were as follows: 1. Older males in both studies generally responded better to one of the active treatments than to a placebo. 2. Older females were more selective and only did well on imipramine. 3. Young females in study 1 did well on placebo and poorly on imipramine. Imipramine's negative effects for these women were discernible primarily on the hostility variables and seemed related to its mild euphoriant and activating properties. 4. Young males showed a marked negative response to a placebo in study 1 and a positive placebo response in study 2. This finding highlighted the need to evaluate placebo response in the context of the active comparison drugs. Hostility was a serious problem for many of these patients and chlorpromazine provided relief from symptoms in this area. This was not true of either of the active drugs in study 2. These results indicated that an analysis of sex differences alone could prove misleading, since there were as many differences in drug response between younger and older women and between younger and older men as there were between the sexes. These findings could be “explained” in terms of relationships among factors such as presenting symptoms, initial severity of illness, sensitivity to side effects, pharmacological action of the study drugs, and placebo response.