Nicotine dependence and psychiatric disorders among young males in Singapore

INTRODUCTION: While the risk for a number of medical illnesses is well established for those who smoke, the risk for psychiatric disorders is not so well studied in Singapore. OBJECTIVES: This study sought to establish the lifetime prevalence of nicotine dependence in a population of young males in Singapore and to establish its relationship with other psychiatric disorders. METHODS: The study was conducted among a cohort of males reporting for their mandatory physical examination prior to their enlistment for National Service in a 1-year period between August 2004 and August 2005. Definitive diagnoses in accordance with DSM-IV criteria were made with the Composite International Diagnostic Interview (CIDI). RESULTS: In the population of 9,702 males assessed by CIDI, the prevalence of nicotine dependence was 12.3%. Academic attainments were significantly poorer in those with nicotine dependence than those without dependence. Nicotine dependence was most strongly associated with delusional disorder and major depressive disorder, which remained even after adjusting for ethnicity and educational attainments (odds ratio [OR] of 59.8 for delusional disorder and OR of 36.3 for major depressive disorder). DISCUSSION: Our study highlights the pervasive extent of nicotine dependence among a population of young men. The pervasiveness of nicotine dependence across different psychiatric disorders suggests either a shared biological substrate or a common consequence of these disorders.