Differences in the Prevalence of Use and Dosage of Psychotropic Drugs by Smoking Status in Inpatient and Outpatient: An Observational, Analytical, Cross-Sectional Study.

OBJECTIVE

To estimate the association between tobacco use and the prevalence of psychotropic medication use and prescribed dosage among inpatients and outpatients with severe mental disorders treated at a neuropsychiatric hospital.

METHODS

Observational, cross-sectional, analytical study conducted on May 3, 2023. Smoking status and prescribed psychotropic medications were recorded for all hospitalized patients and community-based outpatients. Dosages were reported in mg/day, defined daily doses (DDD), and for antipsychotics as chlorpromazine equivalents (CPZeq). Bivariate and multivariate analyses were performed.

RESULTS

Tobacco use data were collected from 325 out of 425 total patients (71.7% male, mean age [SD]: 51.4 [14.4] years, 56% inpatients, 70.2% with schizophrenia and related psychosis). The prevalence of smoking was 72.3%, with differences by gender (78.1% in males vs. 57.8% in females, p < 0.001), and decreased with age (18-39 years: 86.1%; 40-59 years: 71.7%; ⩾ 60 years: 63.2%; p = 0.01). Mean dosages of antipsychotics, clozapine, and olanzapine measured in CPZeq were higher in smokers than in non-smokers by 35.4%, 37.1%, and 33.3%, respectively. After adjusting for confounding factors, smoking was associated with a 21.8% higher dosage of antipsychotics (95% CI: 0.4%-43.2%; p = 0.046), equivalent to an additional 132.2 mg/day (24.2-240.1; p = 0.017) of clozapine and 5.4 mg/day (1.2-9.6; p = 0.012) of olanzapine. The average dosage of sedatives/hypnotics was 45.5% higher among smokers (13.6%-89.5%; p = 0.008).

CONCLUSION

A high prevalence of smoking was found among patients with severe mental disorders, associated with higher average dosages of sedatives/hypnotics and antipsychotics, particularly clozapine and olanzapine.