Why do patients with schizophrenia who have poor insight still take antipsychotics? Memory deficits as moderators between adherence belief and behavior.

While lack of insight is often predictive of antipsychotic nonadherence, some inconsistency in the literature remains unexplained. Verbal memory deficits may moderate the association between insight and adherence. Based on cross-sectional data, outpatients treated with antipsychotics for a psychotic disorder were divided into those with good (n=53) and poor (n=59) memory. Poor insight predicted nonadherence only among the subgroup with relatively good memory (r=0.43; P<0.01), but had no effect in the subgroup with worse memory (r=0.08; ns). Structural equation modelling revealed significant moderation (χ=4.72; df=1; P<0.05), which means that a significantly better model fit was found by allowing the analysis to differentiate between the two memory groups. Thus, poor insight was only associated with poor medication adherence among patients with relatively good memory. We speculate that memory deficits commonly associated with schizophrenia may partly explain why poor insight does not always lead to poor medication adherence.