The Comparison Between Positive and Negative Symptoms Severity in Prolonged Methamphetamine-induced Psychotic Disorder and Schizophrenia

INTRODUCTION: This study aims to compare the positive and negative symptoms of schizophrenia in patients who had psychotic symptoms more than one month after discontinuation of methamphetamine abuse. These factors were analyzed by the positive and negative syndrome scale (PANSS) questionnaire. METHODS: Sixty participants were selected from patients referred to Iran Psychiatric Hospital with psychotic symptoms (delusions or hallucinations, disorganized behavior, and speech). The control group was 30 patients with schizophrenia based on a semi-structured interview according to DSMIV-TR (SCID). Thirty patients with a prolonged methamphetamine-induced psychotic disorder were also placed in the case group. For both groups of patients, questionnaires of PANSS, Brief Psychiatric Rating Scale (BPRS), and Global Assessment Of Functioning (GAF) were filled out after obtaining the companions’ consent. The scale scores were compared between groups. We used the Mann-Whitney and the Chi-square test to evaluate the mean values of PANSS, BPRS, and GAF scores between the two groups. RESULTS: here was an insignificant difference in positive and general pathology scores between the two groups, but the total score of negative symptoms in the schizophrenia group was significantly higher than in the group of prolonged methamphetamine psychotic disorders (P=0.034). Average scores of uncooperativeness (0.008), difficulty in abstract thinking (0.004), motor retardation (0.002), unusual thought content (0.001), and hostility (0.011) in the schizophrenia group were significantly higher than those in the prolonged methamphetamine psychosis. CONCLUSION: The results showed that most of the disturbances in patients with schizophrenia might be more influenced by the expression of cognitive disabilities than those with methamphetamine psychosis. The difference in negative symptom scores suggests that schizophrenia and prolonged methamphetamine psychotic disorder can be two different disorders. HIGHLIGHTS: General and positive symptoms scores don’t have significant differences. Negative symptoms are much more in schizophrenia. Uncooperativeness, unusual thought content and, motor retardation have more scores in schizophrenia. PLAIN LANGUAGE SUMMARY: In clinical practice, Schizophrenia and prolonged methamphetamine-induced psychotic disorder have some similar mental presentations. Additionally, in scientific literature, there is scarce evidence about these similarities. In this regard, this research was designed to investigate the aforementioned obscurity. Determination of similarities and differences between them helps us to address these disorders in terms of treatment and follow-up and awareness of their prognosis of them. This research is a case-control study in which we examine positive and negative psychotic symptoms in schizophrenia and prolonged methamphetamine-induced psychotic disorder. Researchers investigated psychotic symptoms with positive and negative syndrome scale (PANSS), brief psychiatric rating scale (BPRS), and global assessment of functioning (GAF) questionnaires. Moreover, results demonstrate general and positive symptoms scores don’t have many differences but negative symptoms are much more in patients with schizophrenia than in patients with a prolonged methamphetamine-induced psychotic disorder. Also, other features like uncooperativeness, unusual thought content, motor retardation, difficulty in abstract thinking, and hostility have higher scores in schizophrenia than the others. In conclusion, this research showed that these disorders are two distinct disorders with some similarities in positive symptoms but not in all features. So, some studies can be designed about why there are similarities between them?