Cognitive impairment no different in treatment-resistant schizophrenia
Schizophrenia patients who are resistant to first-line antipsychotic treatment do not have increased cognitive impairment, reported Valerie M. Anderson, Ph.D., and her associates.
A total of four groups were assessed using a Brain Resource Centre cognitive battery: 16 schizophrenia patients who responded to first-line antipsychotics, 20 treatment-resistant patients who responded to clozapine monotherapy, and 15 ultra–treatment-resistant patients who responded to antipsychotic polypharmacy.
The control group performed better than any of the schizophrenia groups in all 10 categories measured. However, no clear association of decreased cognitive function was found among the three schizophrenia groups. Treatment-resistant patients had similar or better scores in most categories, especially in verbal fluency. Ultra–treatment-resistant patient scores tended to be slightly worse overall, but the difference was not significant, reported Dr. Anderson of the University of Auckland (New Zealand) School of Pharmacy.
No significant difference was found in age or sex between groups. In the three schizophrenia groups, no significant differences were found in illness duration, Positive and Negative Syndrome Scale scores, or Drug Attitude Inventory–30 scores. In addition, the investigators observed no difference in premorbid IQ; however, the controls had significantly more years of education than did the treatment-resistant patients.
“Functional techniques such as fMRI and electroencephalography should be employed to test for group differences in brain network activation and potential compensatory mechanisms which may explain similar cognitive performances in [treatment-resistant] and [non–treatment-resistant] patients,” the investigators wrote.
Find the full study in Psychiatry Research (doi: 10.1016/j.psychres.2015.10.036).