Evaluation of the Efficacy and Safety of Adding Pregabalin to Antipsychotic Treatment in Patients With Chronic Schizophrenia: A Double-blind Placebo-controlled Clinical Trial

 This study aims to evaluate the efficacy and safety of adding pregabalin to standard antipsychotic treatment in patients with chronic schizophrenia.

In this randomized, double-blind, placebo-controlled clinical trial, participants were 48 male inpatients aged 18-65 years with chronic schizophrenia but with clinically stable conditions. They were randomly divided into two groups of intervention (n=24) and control (n=24). The intervention group received 75 mg of pregabalin per day for three weeks which was increased to 150 mg per day from the fourth week to the end of the study, in addition to standard antipsychotic medication for six weeks. The severity of psychotic symptoms was assessed by the Positive and Negative Syndrome Scale (PANSS), and their movement disorder symptoms were evaluated by the Barnes Akathisia Rating Scale (BARS) and Simpson-Angus Scale (SAS) at baseline and at 3th and 6th weeks of the intervention. Collected data were analyzed using repeated measures ANOVA in SPSS v.20 software, considering P<0.05 as the statistically significance level.

 No significant differences were observed in severity of disease based on the PANSS total score and its three subscales (positive scale, negative scale, and general psychopathology) and in the BARS and SAS scores at the end of 6th week in groups and between the two groups.

Adding 150 mg of pregabalin to the standard antipsychotic treatment of patients with chronic schizophrenia is not effective in improving their psychotic symptoms, but it is well tolerated.