Switching a combination of first- and second-generation antipsychotic polypharmacy to antipsychotic monotherapy in long-term inpatients with schizophrenia and related disorders. The SwAP trial II: Results on side effects

Objective

This study examined the effects of switching antipsychotic polypharmacy (APP) to antipsychotic monotherapy (APM) on various side effects in inpatients with schizophrenia. Side effects of interest included psychic, autonomic, and sexual symptoms, as well as metabolic side effects and movement disorders.

Method

A 9-month parallel randomized open-label clinical trial was conducted involving 136 chronic inpatients from two psychiatric hospitals in the Netherlands. Participants were randomly assigned to either a STAY or a SWITCH group. The SWITCH group underwent a 3-month tapering-off period in which either first-generation or second-generation antipsychotic medication was discontinued, followed by APM. Patients were assessed at baseline and at follow-up assessments at 3, 6, and 9 months. Psychic, neurological, autonomic, and sexual side effects were evaluated using the UKU Rating Scale, while movement disorders were measured with the St. Hans Rating Scale. Various metabolic parameters were also recorded.

Results

In the STAY group, side effects remained generally stable over time, except for a slight reduction in sexual desire. In contrast, the SWITCH group experienced significant reductions in psychic and autonomic symptoms, as well as improvements in akathisia, parkinsonism, and dyskinesia. There were no changes in dystonia, paresthesia, epilepsy, or sexual symptoms for this group. Notably, the SWITCH group also showed significant reductions in BMI and body weight.

Conclusion

Switching APP to APM in long-term inpatients reduces the severity of various side effects, including movement disorders and metabolic side effects.