The effect of anticholinergic burden of psychiatric medications on major outcome domains of psychotic disorders: A 21-year prospective cohort study

Background: Most medications used to treat psychotic disorders possess anticholinergic properties. This may result in a considerable anticholinergic burden (ACB), which may have deleterious effects on long-term outcomes. The extent to which cumulative ACB over years of treatment with psychotropic medications impacts different outcome domains remains unknown.

Methods: This was a naturalistic study of 243 subjects with first-episode psychosis aimed at examining the cumulative effect of ACB of psychotropic medications administered over the illness course (ACB-years exposure) on several outcome domains assessed after a mean 21-year follow-up. Associations between ACB and the outcomes were modelled accounting for relevant confounding factors by using hierarchical linear regression analysis.

Results: Over the study period, 81.9 % of the participants were dispensed at least one drug with strong anticholinergic effects for at least 1 year; at the follow-up visit, 60.5 % of the participants continued to take medications with strong ACB. ACB-years exposure was uniquely related to severity of negative symptoms (β = 0.144, p = 0.004), poor psychosocial functioning (β = 0.186, p < 0.001) and poor cognitive performance (β = -0.273, p < 0.001). This association pattern was independent of a schizophrenia diagnosis. Most of the associations between ACB at the follow-up visit and the outcomes were accounted for ACB-years exposure.

Conclusion: Lifetime ACB of psychotropic medications has deleterious effects on the outcome of psychotic disorders. Clinicians should avoid prescribing medications with strong ACB, since there are numerous alternatives within each psychotropic drug group for prescribing medications with low ACB.