Medication adherence in schizophrenia.

Non-adherence is a major problem in the treatment of schizophrenia. Its high prevalence, potentially severe consequences and associated costs make the study of this phenomenon a priority issue. In this article, basic non-adherence concepts of prevalence, consequences, evaluation methods, methodological restrictions of available studies, risk factors and intervention strategies, are reviewed. Studying non-adherence risk factors is a necessary step toward designing adequately oriented intervention strategies. An operative definition of adherence and good knowledge of its evaluation methods are essential to study this phenomenon. Unfortunately, most available studies contain methodological restrictions, especially concerning the evaluation methods, and an agreed operative definition of adherence has only very recently been reached. Knowing non-adherence risk factors, intervention strategies and available evidence on their effectiveness is essential in making treatment decisions in daily clinical practice.