EFFECTS OF PAST HISTORY OF MAJOR DEPRESSION ON SMOKING CHARACTERISTICS, MONOAMINE OXIDASE-A AND OXIDASE-B ACTIVITIES AND WITHDRAWAL SYMPTOMS IN DEPENDENT SMOKERS

Past history of major depression is more common in smokers than in non -smokers. We have shown in a previous study that lifetime prevalence o f major depression is higher in dependent smokers and they have lower monoamine oxidase-A and -B activities than non-smokers. Because severa l studies have found an association between MAO-B activity and depress ion we analysed data of these smokers to assess:whether past history o f major depression is associated with reduced monoamine oxidase activi ties (A and B) or not. Further, we tried to characterize smokers with past history of major depression and its effect on withdrawal symptoms . The data of 88 dependent smokers (Fagerstrom Tolerance Questionnaire score greater than or equal to 6 and smoking greater than or equal to 20 cigarettes/day) who participated in a smoking cessation study were analysed. Smokers with past history of major depression but without c urrent illness did not differ in demographic and smoking characteristi cs from smokers without past history of major depression. Smokers with past history of major depression were mainly women and had lower body mass index. Adjusted for gender and body mass index dependent smokers with or without past history of depression had similar MAO-A and MAO- B activities but smokers with past history of major depression had sig nificantly lower resting plasma norepinephrine levels. Smokers with pa st history of depression had not significantly higher ratings for depr ession (Montgomery-Asberg Depression Rating Scales) and anxiety (Hamil ton Anxiety Scales) and smoking cessation did not exacerbate these rat ings (assessed up to 3 months) and none had depressive episode during the postcessation period up to one year. Past history of depression wa s associated with higher scores on 'expressed sadness' and 'depressive mood'. Abstinent smokers with past history of depression had signific antly higher ratings in one of the seven ratings of a 6 months period for craving (day 28), anxiety (day 7) and total withdrawal symptom sco re (day 7) when compared to those who had no past history of major dep ression. It is concluded that (i) past history of major depression is more frequent in female smokers (ii) smokers with past history of depr ession may have more intense withdrawal symptoms (craving and anxiety) at some time after cessation; and (iii) past history of depression do es not affect monoamine oxidase activities, therefore, reduced monoami ne oxidase activities found in previous studies are possibly character istic features of smoking. (C) 1997 Elsevier Science Ireland Ltd.