Trihexyphenidyl (THP) is an anti-Parkison and anticholinergic drug. It is essentially prescribed by psychiatrists in order to treat abnormal movements and Parkinsonism induced by antipsychotics. However, in unusual practice, the THP is widely used by patients.

To assess different factors associated to the prescription of trihexyphenidyl in patients treated with neuroleptics.

A cross-sectional, descriptive, comparative and analytical study among 153 patients followed in outpatients clinics and treated by antipsychotics.

During a six-month period, 153 patients were interested by the study. In total, 79.73% of them were receiving a treatment by THP. Mean age was 47.79 years old. Almost patients were married (44.1%), having a primary level education (46.7%) and jobless (66.7%). Mean factors associated to THP prescription were: hospitalization in a psychiatry unit (P = 0.025), good evolution of mental disorder during hospitalization (P = 0.008), regular follow-up (P = 0.005), episodic evolution and existence of residual symptoms (P = 0.001), personality disorder (P = 0.025) and somatic comorbidities (P = 0.001). Prescription was crucial in order to indicate necessity of THP. Doses of neuroleptics were a determinant factor (P = 0.0001). Forty-one percent of patients were receiving more than one treatment (P = 0.0001). In most cases, prescription consists of classic antipsychotics (67.60%).

Prescription of THP should be argued, considering different factors associated to the prescription, in order to prevent misuse of the drug.

The authors have not supplied their declaration of competing interest.