Relationship between tobacco smoking and positive and negative symptoms in schizophrenia

In an attempt to understand the reasons behind the high prevalence of tobacco smoking in patients with schizophrenia, the study examined whether specific symptoms of schizophrenia were associated with smoking. Standardized assessments of nicotine dependence (Fagerstrom Test for Nicotine Dependence) and psychopathology (Positive and Negative Syndrome Scale) were performed on 87 inpatients with schizophrenia. Nearly 76% of patients were nicotine dependent. Significant positive correlations were found between Fagerstrom scores and the total negative symptom score and scores on the negative symptom subscales of blunted affect, social withdrawal, difficulty in abstract thinking, and stereotyped thinking. Fagerstrom scores were also significantly associated with impairment in attention, orientation, thinking, and impulse control. Positive symptoms were not significantly associated with smoking. A combination of negative symptoms, duration of illness, and alcohol use optimally predicted smoking in the sample. Neurobiological mechanisms could possibly underlie some of our findings and require further investigation.