Individuals who suffer from schizophrenia may be more inclined to smoke cigarettes because the nicotine reduces negative symptom severity, researchers report.
Negative symptoms are defined as a decline or absence in the traits needed for normal functioning. These include loss of interest in everyday activities, lack of emotion, social withdrawal, reduced ability to plan or carry out activities, neglect of personal hygiene, and loss of motivation.
“Although smoking has a wide range of well-established ill effects on human health, these findings do raise the possibility of exploring nicotinic pathways for novel treatments of schizophrenia,” said the researchers.
In two large independent samples, researchers found that Chinese men with schizophrenia were more than twice as likely to smoke cigarettes compared to those without schizophrenia, and half as likely to quit smoking.
Among the combined 1,139 male patients with schizophrenia, smoking was found to be consistently and significantly associated with reduced negative symptoms on the Positive and Negative Syndrome Scale, and it remained consistent even after researchers took into account antipsychotic use.
This was the only one of the five dimensions of symptomatology measured that was significantly reduced, however. Smoking had no effect on positive, cognitive, or depressive symptoms, overall, and although it seemed to increase excitement in the two samples combined, the link was not significant in the individual study samples.
“These observations support the hypothesis that smoking alleviates negative symptoms in schizophrenia patients, which may account for the heavier smoking pattern among schizophrenia patients,” said lead researcher Jimmy Lee of the Institute of Mental Health at Woodbridge Hospital, Singapore, and colleagues.
Their results revealed that 42.4 percent of patients with schizophrenia were current smokers, compared with 16.8 percent of 535 individuals from the general population. The lifetime prevalence was 54.1 percent versus 29.3 percent.
Contrary to the notion that schizophrenia patients may smoke to reduce the side effects of their antipsychotic treatment, smoking was not associated with the use of antipsychotics or their side effects.
The researchers note that transdermal nicotine treatment has already been proven to increase short-term cognitive function in non-smoking schizophrenia patients.
Schizophrenia is a rare but serious psychiatric disorder, usually beginning in late adolescence, and is characterized by hallucinations, delusions, paranoia, cognitive impairment, social withdrawal, self-neglect and loss of motivation and initiative.
Source: PLoS One