Inclusion criteria:
18-65 years old male patients.
Patients with a diagnosis of schizophrenia based on DSM-5 criteria for at least two years who should still be symptomatic despite treatment with antipsychotic medications.
Patients should be treated with antipsychotic medications for at least one year, and the type and dose of their antipsychotic medications should remain constant for the last three months.
If they are taking medications such as mood stabilizers or antidepressants with their antipsychotic treatment regimen, their type and dose will remain the same for three months before the start of the study and during the study.
If they are taking anticholinergic drugs (which include bipyridine or trihexylphenidyl) in combination with their antipsychotic treatment regimen for treatment or prevention the Movement side effects of antipsychotics, the type and dose of them remain stable for three months before the start of and during the study.
Exclusion criteria:
Going to the acute phase of the disease means a 20% increase in the overall score of PANSS (Scizospheria positive and negative evaluation criteria)
Patients with acute suicidal behavior or a history of suicide last year, associated psychiatric disorders such as schizo-effective or other psychotic disorders, mental retardation or other cognitive impairment, bipolar disorder and depression, anxiety disorders such as current panic disorder or obsessive-compulsive disorder, Post-traumatic stress disorder, eating disorder
History of substance abuse dependence (substance dependence criteria DSM-5) or abuse of substances in the three months prior to the start of the study or positive urine screening test for the substance at the beginning of the study
Patients under ECT in the last six months
People with thoughts or actions to harm themselves or others during the study or in the 6 months before the study
People with mental retardation
Patients with neurological disorders such as dementia, delirium, uncontrolled seizures, head trauma, seizure disorder (other than fever-related) and neurodegenerative diseases (such as Alzheimer's, Parkinson's, Stroke, and multiple sclerosis)
People with underlying medical conditions are uncontrolled
Patients with a history of NMS
Patients treated with drugs that affect the patient's cognitive status are based on the criteria of Drugs on the Anticholinergic Burden (ACB) scale (17), such as drugs with anticholinergic properties (except biperidin and trihexifenidyl), hypnotic antihistamines. , Antidepressants
Patients with sensitivity to rivastigmine or other components of the drug or placebo
Patients with rivastigmine in the last 6 months