Schizophrenia is a complex and heterogeneous disorder, with multiple, and varying symptoms. For this very reason it cannot be distinguished based on inherent disorder process, effects of medication therapy, or continuous longterm hospitalization. To date, much effort has been made to identify drugs, effective in the treatment of its symptoms. Yet, despite great progress made in this path, treatment of these symptoms has not had any significant success. Thus, the aim of the present study is to examine the effect of adding the drug Pregabalin to the customary drugs of the patients with schizophrenia for improvement in positive, negative, and general signs of these patients. The method used, in this study, was quasi-experimental. The type of objective was functional, having pre-test – post-test design, with a control group. The population, in the study, consisted of 60 schizophrenic patients, hospitalized in the serenity center, who had been diagnosed according to the standards of DSM – 5, and were placed on a fixed dose, of customary medications, for a minimum of 2 months. 30 individuals were selected according to random table, and, on that basis, were placed in two groups of test and control, with 15 members each. The measurement instrument used was PANSS. Pre-test was performed by having all 30 patients filling out the PANSS questionnaire. Then, Pregabalin (50 mg.) was administered, to the test group, two times a day, for a period of 6 weeks. No medication was added to that of the control group. Following a two-week period, both groups were reassessed using PANSS test. The obtained results were analyzed using covariance analysis, using SPSS software. Results of the study indicated that adding Pregabalin did not result in improvement in any of the symptoms (positive, negative, general, agitation, anxiety, and depression) in schizophrenia patients. The study results indicated that although symptoms (positive, negative, general, agitation, anxiety, and depression) were lowered in patients with schizophrenia, but this decline was not significant, and no significant difference was observed between the two groups of test and control.