Objective: Problem with memory and attention is a neglected aspect of schizophrenia.
The most affected domains are attention, working memory and semantic memory.
The impairments are, like the negative symptoms, basically stable and independent of the
positive symptoms. Since such deficits do not respond to antipsychotics, during the past years
some approaches have been done by different acetylcholinesterase inhibitors. Assessment of
the effectiveness of rivastigmine, as an add-on therapy, on clinical symptoms of schizophrenia,
was the main objective of the present study.
Method: 46 male inpatients, with diagnosis of schizophrenia, entered into a 12-week, doubleblind,
clinical trial for random assignment to placebo or rivastigmine, as adjuvant to their current
antipsychotic medication. ‘Positive And Negative Symptom Scale [PANSS]’ and ‘Mini
Mental State Examination [MMSE]’ had been used as the main outcome scales. ‘Clinical
Global Impressions- Global Improvement [CGI-I]’ and ‘Extrapyramidal Symptom Rating
Scale [ESRS]’ had been used as the ancillary scales.
Results: According to the findings, except than significant enhancement of MMSE by rivastigmine
[p<0.001], no significant improvement in positive, negative and general psychopathology
of schizophrenia was evident in the target and control groups. Also, except than
significant enhancement of CGI-I by rivastigmine in intra-group analysis, no significant improvement
was apparent in between- group analysis. ESRS, too, did not display any significant
alteration in either group. Finally, effect size [ES] analysis exhibited a large improvement
of MMSE by means of rivastigmine.
Conclusion: Disregard to positive or negative symptoms, rivastigmine can significantly improve
the cognitive function of schizophrenic patients, which may be favorable for psychosocial intervention
or rehabilitation of this group of patients.