How do socio-demographic and clinical factors interact with adherence attitude profiles in schizophrenia? : a cluster-analytical approach

Knowledge regarding socio-demographic and clinical risk factors of medication nonadherence does not always help in addressing adherence in individual patients. Classifying patients according to subjective adherence influencing factors may aid practitioners in choosing adequate strategies for improving medication adherence. A total of 171 outpatients with schizophrenia and schizoaffective disorder were classified according to factors influencing their medication adherence assessed using the Rating of Medication Influences Scale. Additionally, psychotic symptoms, depression, and insight, also known to influence pharmacological treatment motivation, were assessed. A cluster analysis yielded 3 groups that were distinguished both by the relative ranking of adherence influences and by specific associations with risk factors of nonadherence. For the "Interpersonal, Future-oriented Group" (n=59, 35% of the sample), interpersonal factors (positive therapeutic relationship, positive attitudes of significant others towards medication), immediate positive consequences of the medication intake (daily benefits, no perceived pressure to take medication), and avoiding future negative consequences of non-compliance, such as relapse and re-hospitalization, were essential for adherence. The "Autonomous, Future-oriented Group" (n=69, 40% of the sample) appraised interpersonal factors as being less important as compared to the other groups. This group exhibited significantly fewer depressive symptoms than the first group and had significantly more stable partnerships as compared to the other groups. The "Autonomous, Present-oriented Group" (n=43, 25% of the sample) was mainly motivated by immediate positive consequences and displayed higher levels of cognitive disorganization and negative symptoms than the second group, as well as the lowest level of insight of all groups. Treatment strategies addressing adherence enhancement in schizophrenia may profit by considering both the patient's subjective adherence attitude profile as well as the specific pattern of risk factors for nonadherence including depression, lack of insight, negative syndrome, cognitive disorganization and socio-demographic factors, which are differentially associated with each adherence attitude profile.