Nicotine Misuse and Treatment of Schizophrenia Exacerbations in Men: An Observational Study in Poland.

Background/Objectives: Prevalence of nicotine misuse among schizophrenia patients is significantly higher than in the general population and is estimated at 70-90%. Past studies have shown that nicotine misuse affects the course of the schizophrenic process in terms of frequency of hospitalizations, age of the first onset, social functioning, and pharmacotherapy, among others. This study aimed to examine associations between smoking and psychopathology, course of hospitalization, doses of administered antipsychotics, and severity of adverse events in men hospitalized for exacerbations of schizophrenia. Methods: Protocol procedures were performed in 81 men (40 smokers and 41 non-smokers) and included assessments with a structured interview, laboratory tests, the Positive and Negative Syndrome Scale (PANSS), Montgomery and Asberg Depression Rating Scale (MADRS), Fagerstrom Test for Nicotine Dependence (FTND), and extrapyramidal symptom scales. Results: In both groups, a comparable number of patients met the criteria for remission. However, in the pre-discharge period, non-smokers had more severe depressive symptoms measured by MADRS and PANSS than smokers, as well as more severe and more frequent extrapyramidal symptoms. In contrast to previous research, significantly higher doses of antipsychotics measured in chlorpromazine equivalent (CPZE) doses were administered in non-smokers than in smokers (881.1 versus 689.3, p = 0.0305). Non-smokers were also more likely to need high doses of medication (>1000 milligrams CPZE) than smokers (43.9% versus 20%, p = 0.0212). However, these associations lost statistical significance after adjustment for initial severity and treatment-related factors. Comparison of CPZEs in the context of metabolic pathways suggests that variations in doses are independent of metabolism by cytochrome P450 1A2 (CYP1A2). The results also indicate that nicotine may help to differentiate between negative and depressive symptoms. Conclusions: In this male inpatient sample, smokers showed lower depressive symptom scores. Although smoking may affect some symptoms of schizophrenia according to the self-medication hypothesis, therapeutic measures aimed at smoking cessation should not be delayed in this group of patients.