Clinical features and predictors of non-response in severe catatonic patients treated with electroconvulsive therapy.

Objective: To explore the demographic and clinical features of severe catatonic patients, comparing responders and non-responders to ECT in order to detect possible predictors of non-response.

Methods: This naturalistic study included 59 catatonic inpatients with a diagnosis of mood disorder according to DSM-IV-TR criteria. All patients were treated with bilateral ECT and evaluated before and after ECT course. The response to ECT was defined as a Clinical Global Impression (Improvement subscale) rating 1 'very much improved' or 2 'much improved'. Clinical variables were compared between responders and non-responders; logistic regression was used to predict the probability of non-response, with regard to the symptoms presented by the patients.

Results: The response rate was 83.1%. Non-responders ( = 10) to ECT showed neurological comorbidities, treatments with dopamine agonists and anticholinergic drugs, waxy flexibility, and echophenomena more frequently than respondents ( = 49). Echophenomena resulted a significant predictor of non-response in the multivariate analysis.

Conclusion: In line with previous reports, ECT resulted effective in the vast majority of severe catatonic patients. The association between ECT resistant catatonia and neurological comorbidity, use of dopamine-agonist and anticholinergic medications is consistent with the hypothesis that ECT is more effective in 'top-down' than in 'bottom-up' variant of catatonia.Key pointsCatatonic symptoms are frequently associated with severe and psychotic mood disorders.Electroconvulsive therapy is effective in treating most forms of severe catatonia.Neurological comorbidity and the presence of 'echopraxia/echolalia' could represent predictors of non-response to ECT.