Memantine effect in the treatment of residual symptoms in patients with schizophrenia

INTERVENTION: Intervention 1: Subjects in the intervention group receive memantine with an initial dose of 10 mg/day for first week, which is increased to 20 mg/day on the second week and continue with the same dose until the end of the study along with their antipsychotic regimen for 8 weeks . Intervention 2: The control group receive their antipsychotic regimen with placebo for eight weeks. Placebo Subjects in the intervention group receive memantine with an initial dose of 10 mg/day for first week, which is increased to 20 mg/day on the second week and continue with the same dose until the end of the study along with their antipsychotic regimen for 8 weeks . The control group receive their antipsychotic regimen with placebo for eight weeks. Treatment ‐ Drugs CONDITION: Schizophrenia. ; F20.5 PRIMARY OUTCOME: Severity of psychiatric symptoms assesment. Timepoint: Baseline and weeks 3, 6 and 8. Method of measurement: Positive and Negative Syndrome Scale (PANSS). SECONDARY OUTCOME: Clinical Global Impression of Improvement (CGI‐I). Timepoint: Baseline and weeks 3, 6 and 8. Method of measurement: Clinical Global Impression of Improvement (CGI‐I). Clinical Global Impression of Improvement (CGI‐S). Timepoint: Baseline and weeks 3, 6 and 8. Method of measurement: Clinical Global Impression of Improvement (CGI‐S). Depressed mood assessment. Timepoint: Baseline and weeks 3, 6 and 8. Method of measurement: Calgary Depression Scale for Schizophrenia. Nigella sativa induced akathisia assessment. Timepoint: Weekly. Method of measurement: Barnes Akathisia Scale. Nigella sativa induced Movement disorder assessment. Timepoint: Weekly. Method of measurement: Abnormal Involuntary Movement Scale. Severity and type of obsessive compulsive symptoms assessment. Timepoint: Baseline and weeks 3, 6 and 8. Method of measurement: Yale–Brown Obsessive Compulsive Scale. INCLUSION CRITERIA: INCLUSION CRITERIA: 1‐ Male or female are recruited from in‐patient units in yahyaneghad hospital located in Babol in the north of Iran 2‐ 18–65 years at the time of screening 3‐ With a diagnosis of schizophrenia(paranoid, disorganized, catatonic, or undifferentiated type)or schizoaffective disorder, based on the Structured Clinical Interview for DSM‐V and they are suffering from the disease for more than 2 years with residual symptomatology despite antipsychotic treatment 4‐ All patients are on antipsychotics for at least 1 year and a stable dose for at least 2 month are included in the trial and the antipsychotics dose remain unchanged during the trial. 5‐ Mood stabilizers (lithium and divalproex) and antidepressants (only the selective serotonine reuptake inhibitors (SSRIs) venlafaxine, and mirtazapine) were permitted as part of antipsychotic pharmacotherapy. Dose of these drugs must be stable for at least 2 mon