The deleterious effects of anticholinergic properties on cognition in patients with schizophrenia are well known. There is strong evidence that a higher anticholinergic load
impairs cognition, especially verbal memory and attention, and there is improvement in memory tasks under decreasing anticholinergic medication doses [41, 42]. The adverse effects
of anticholinergic load are more prominent in patients with a higher risk of cognitive impairment (e.g., patients with neurological diseases or psychiatric disorders or the elderly).
The deleterious cognitive effect of long-term use has been recently reviewed [43].We also expected to find higher levels of cognitive impairment under increasing CDD load. No significant effects were found under increasing CDD load in the whole sample, or in the subgroups. This may be because equivalent dose calculations based on Minzenberg et al. were insufficiently precise due to the more diverse pharmacological regimes in our sample and/or insufficient data for anticholinergic equivalent doses for some drugs.
Given these considerations, our finding of a trend effect on EF under increasing CDD is likely to be coincidental, especially as it could not be reproduced for CDD in the whole sample or in Group A.