The aim of the current study was to examine the associations between nicotine dependence and quality of life (QOL) among individuals diagnosed with major depressive disorder (MDD) or psychotic disorders. Methods: A total of 378 participants diagnosed with either MDD or psychotic disorders were recruited. The Fagerstorm Test for Nicotine Dependence was used to measure the level of nicotine dependence. The SF-12 health survey questionnaire was used to measure the QOL. Results: The prevalence of nicotine dependence was 23.3% in this sample population. For those diagnosed with MDD, moderate level of nicotine dependence was negatively associated with Vitality and Mental Component Score. For those diagnosed with a psychotic disorder high nicotine dependence was negatively associated with Role Emotional, Mental Health and Mental Component Score. Discussion: Compared to the general population, the prevalence of smoking in this psychiatric population was 2.4 times higher, while that of nicotine dependence was seven times higher. Individuals with psychotic disorder generally reported better QOL as compared to individuals with MDD. QOL differed across diagnostic groups with regards to socio-demographics, such as age, ethnicity, marital status, education, employment status and monthly income. Among individuals with MDD and psychotic disorders, different levels of nicotine dependence resulted in different levels of association with QOL. More research is needed to better understand the differences in QOL among the varying levels of nicotine dependence.
Keywords: major depressive disorder; nicotine dependence; psychotic disorder; quality of life.