Adolescent mental health predicts quitting smoking in adulthood: a longitudinal analysis.

OBJECTIVES: Several studies have reported an association between cigarette smoking and psychiatric illness. A common finding is that the prevalence of psychiatric illness among former smokers is much lower than among current smokers and is often similar to that among never-smokers. There are two alternative causal explanations for this association: either improved mental well-being results from smoking cessation; or those with poorer mental well-being are less successful at smoking cessation. The objective was to analyse a unique longitudinal data set to shed light on the direction of causality and to distinguish between these alternative explanations.
METHODS: Information on smoking status and indicators of poor mental well-being from childhood and adolescence was collected at age 18 in 1969 from 49 321 men at compulsory conscription for military service. Follow-up data on smoking status were collected among a random subset (n = 694) who participated in one or more annual national Swedish Surveys of Living Conditions in 1981-2001.
RESULTS: Approximately half of the smokers at age 18 in 1969 had quit by the time they were resurveyed (1981-2002). Those who had not quit and who reported smoking more than 10 cigarettes/day at age 18 (called persistent heavy smokers), were more likely to have had childhood and adolescent indicators of poor mental health measured at age 18 in 1969 than non-smokers or quitters.
CONCLUSION: Our findings indicate that men who would subsequently be successful at smoking cessation reported better mental health and a lower prevalence of childhood mental health indicators at age 18 than persistent heavy smokers.