Smoking Behavior and its Effect on Psychiatric Symptoms of Patients with Stable Schizophrenia

Schizophrenia is a common and clinically disabling mental disorder. Many patients with schizophrenia smoke. Research on the effects of smoking on schizophrenia's symptoms are inconsistent.

The study intended to investigate the smoking status of patients with stable schizophrenia to determine the effects of smoking on schizophrenia-related symptoms.

The research team performed an case-control study.

The study took place at Beijing Huilongguan Hospital in Beijing, Changping District, China.

Participants were 160 patients at the hospital who had been diagnosed with stable schizophrenia between April 2018 and March 2020.

The research team divided participants into two groups based on their current smoking status: (1) a smoking group with 72 participants and (2) a nonsmoking group with 88 participants.

The research team: (1) examined the types of antipsychotic drugs that participants received; (2) used a schizophrenia-related scale, the Positive and Negative Syndrome Scale (PANSS), to examine participants' status; (3) examined the smoking habits of the smoking group; and (4) analyzed the correlation between the PANSS score and the smoking group's smoking index.

No significant difference existed between the groups in the type of medicine used (P > .05). The smoking group's PANSS total (P = .014), positive symptom (P = .039), and negative symptom (P = .003) scores were significantly lower than those of the nonsmoking group (P < .05). No significant difference existed between the groups in the general psychopathological symptom score (P > .05). The smoking group started smoking between 13 and 24 years of age, with an mean age of 19.11 ± 4.10 years. The group smoked 10-30 cigarettes/d, with a mean smoking amount of 18.4 ± 3.1 cigarettes/d, and the smoking index was 344.7 ± 48.0. The smoking group's smoking index was significantly negatively correlated with the positive symptom, negative symptom, and total PANSS scores (all P = .000). No correlation existed between the smoking index and the general psychopathological symptom score (P > .05).

Smoking patients with stable schizophrenia generally exhibit fewer symptoms than nonsmoking patients, which relate to the alleviation of mental tension that smoking can provide.