History of tobacco smoking and alcohol use can predict the effectiveness of electroconvulsive therapy in individuals with schizophrenia: A multicenter clinical trial.

Background: Current research has found that factors such as gender, age, and family history can predict the efficacy of electroconvulsive therapy (ECT) in individuals with schizophrenia. In our clinical practice, we anecdotally observed that tobacco smokers and alcohol drinkers with schizophrenia seemed to respond more effectively to ECT than non-smokers and non-drinkers. The current study aimed to examine whether history of tobacco smoking or alcohol consumption serve as indicators for predicting therapeutic efficacy of ECT in individuals with schizophrenia.

Methods: A total of 481 individuals receiving ECT combined with antipsychotic medication (ECT + AP medication) completed a two-week (six sessions of ECT) follow-up; 106 individuals receiving only antipsychotic medication (AP medication) also completed a two-week follow-up. Smoking, alcohol consumption, and AP medication usage was recorded for these individuals. Severity of psychotic symptoms was assessed using the Positive and Negative Syndrome Scale (PANSS).

Results: ECT + AP medication: Compared to schizophrenic individuals without a history of smoking (non-smokers), those with a history of smoking (smokers) showed a high decrease in negative symptoms (36.96% vs 24.76%; F = 5.974, p = 0.015). While, compared to individuals without a history of alcohol consumption (non-drinkers), those with a history of alcohol consumption (drinkers) showed a high decrease in positive symptoms (48.90% vs 41.47%; F = 5.074, p = 0.025). AP medication: No differences were found in symptom reduction between smokers and non-smokers or between drinkers and non-drinkers (p > 0.05).

Conclusions: Smoking history in schizophrenic individuals independently predicts better improvement in negative symptoms after ECT, while alcohol consumption history independently predicts better improvement in positive symptoms after ECT. This is a clinically significant finding.