Smoking Initiation, Age at Onset of Symptoms and Suicide Attempts Among Patients With Bipolar Disorder: Comparisons With Non-Psychiatric Adults.

INTRODUCTION

The prevalence of tobacco smoking and high nicotine dependence (ND) in bipolar disorder (BD) is higher than in the general population but lower than in schizophrenia. This study aims to analyse the relationship of smoking behaviours, including age at onset of daily smoking (AODS), with age at onset of BD and course-of-illness variables -particularly recurrent suicide attempt- in a community sample of BD patients, also compared in their smoking behaviour variables with a sample of non-psychiatric adults.

METHODS

Samples of 108 patients with BD and 290 non-psychiatric adults were compared in their smoking habit. High ND was defined by a score of ≥ 6 on the Fagerström Test for Nicotine Dependence. Logistic regression analyses were employed to identify factors associated with daily smoking and high ND. Hazard curves were used to compare AODS between patients and controls and, among patients, age of BD onset between smokers and non-smokers. Within-subject survival times -AODS and the age at onset of BD symptoms- were compared with a multi-state illness-death model.

RESULTS

Compared with controls, BD patients showed higher prevalences of current daily smoking (44% vs. 34%) and high ND (25% vs. 9%); and lower smoking cessation rates (23% vs. 38%). Among BD patients, recurrent suicide attempt showed a strong independent association with both daily smoking and high ND. AODS was later in BD patients than the control group. Among patients, illness onset was earlier in smokers and AODS was earlier than illness onset.

CONCLUSION

Addressing tobacco consumption should be an integral component of BD prevention and treatment strategies.