Anticholinergic activity linked to cognitive performance in schizophrenia
MedWire News: Serum anticholinergic activity in schizophrenia patients is associated with impaired verbal working memory and verbal learning and memory, and with a lowered response to an intensive course of computerized cognitive training, show study results.
These findings underscore the cognitive cost of commonly used schizophrenia medications that raise serum anticholinergic activity.
For the study, Sophia Vinogradov (University of California, San Francisco, USA) and colleagues randomly assigned 55 schizophrenia outpatients to either auditory computerized cognitive training or a computer games control training.
The researchers measured serum anticholinergic activity at study entry (n=49) and performed a neurocognitive battery based on the Measurement and Treatment Research to Improve Cognition in Schizophrenia (MATRICS) initiative at baseline and after the intervention.
Over half of the 49 patients had anticholinergic activity levels of 3 pmol/ml or more at baseline– a level previously associated with a 13-fold increased risk for having a score of 24 or less on the Mini Mental State Examination compared with undetectable levels.
Similarly, Vinogradov and co-authors found a significant relationship between anticholinergic burden and baseline performance in working memory and verbal learning and memory, with serum anticholinergicity accounting for 7% of the variance, independent of IQ, age, and symptom severity.
Patients (n=25) who completed the computerized cognitive training showed a significant gain in global cognition compared with those in the control condition, at changes of 0.39 versus 0.05. Improvements were also seen in verbal learning and memory and verbal working memory in patients completing auditory training compared with controls.
However, the improvement in global cognition was significantly negatively correlated with anticholinergic burden, with serum anticholinergic activity accounting for 20% of the variance in global cognition change score, independent of covariates.
“These results indicate that anticholinergic burden had a negative impact on schizophrenia participants’ global response to the cognitive training,” write the authors in the American Journal of Psychiatry.
Additionally, the team found that patients in the lowest anticholinergicity quartile (0.8 pmol/ml), who were on more conservative medication regimens, had higher ratings on positive symptoms but also showed a greater response to cognitive training compared with patients in the upper quartile (22 pmol/ml).
“We speculate that a conservative approach to the pharmacologic treatment of schizophrenia, combined with behavioral techniques for managing low-level psychotic symptoms, might optimize patients’ ability to benefit from cognitive interventions,” concludes the team.
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By Ingrid Grasmo