For resistant schizophrenia, the only approved treatment is clozapine. However, clozapine is underused, mainly due to its wide range of side-effects. Secondary effects differ amongst antipsychotics (Leucht et al., 2009). Despite that there is no good evidence that combined antipsychotics offer any advantage over the use of a single antipsychotic, combination increases the frequency of adverse events (Maudsley guidelines).

To compare the side-effect profile between clozapine and non-clozapinepatients.

To provide evidence that clozapine patients do not show a worse side-effects profile.

We cross-sectionally analysed all patients from a Spanish long-term mental care facility (n = 139). Schizophrenic/schizoaffective patients were selected (n = 118) and their treatment was assessed, 31 patients used clozapine. We paired clozapine and non-clozapine patients by sex and age and assessed antipsychotic side effects and possible confounder variables.

Our sample was 27 clozapine patients and 29 non-clozapine patients. 67,9% were male with a mean age of 51.3 (SD 9.6) years. For continuous variables: age, BMI, waist/hip, cholesterol, TG, glucose, prolactin, heart-rate, blood pressure, sleeping hours, the only statistical differences found were lower heart-rate (P = 0.001) in clozapine group and higher salivation subscale of SAS (P = 0.002) in clozapine group. For discrete variables: monotherapy, obesity, overweight, metabolic syndrome or possible confounders as propranolol, laxative, diet, antiglycemiant or insulin, fibrates or statins, antihypertensive or anticholinergic, no statistical differences were found.

We did not find differences in cardiometabolic parameters, which are the main barrier to prescribing clozapine, probably due to the concomitant use of other drugs in both groups.

The authors have not supplied their declaration of competing interest.