Partial compliance in schizophrenia and the impact on patient outcomes

Abstract

This review evaluates the impact of partial compliance on treatment outcomes in schizophrenia and discusses strategies that may be implemented to enhance compliance. As such, a search of English language articles evaluating compliance in schizophrenia was performed using Medline and EMBASE, with no time limits. Abstracts and posters presented at key psychiatry congresses were also reviewed. Results demonstrated that partial compliance with antipsychotic medication is a significant barrier to achieving optimal outcomes in schizophrenia. The problem increases with the duration of treatment, and is difficult to monitor. The impact of partial compliance is significant, leading to increases in psychotic symptoms, the risk of relapse and rehospitalization, and even suicide. Compliance is a complex phenomenon, influenced by aspects of the illness itself such as cognitive impairment and patients' health beliefs. The patient's environment and therapeutic alliance also influence medication compliance. Behavioural and pharmacological measures should be used together to improve compliance. While atypical antipsychotics have demonstrated improvements in psychotic symptoms, insight and cognition, these may not be enough to ensure compliance with oral daily medication. Long-acting risperidone may therefore bring together the benefits of the atypical antipsychotics with the long-acting injection delivery system required to build a platform for improved outcomes.

Introduction

Patient compliance has been defined as ‘the extent to which a person's behavior coincides with the medical advice he/she has received’ (Kampman and Lehtinen, 1999). Poor compliance, often defined by physicians as adhering to < 70% of prescribed medication during the last week, is one of the primary barriers to successful management and optimal outcomes in patients with schizophrenia (Keith and Kane, 2003). Schizophrenia patients may fail to take medication, discontinue therapy prematurely, or deviate from the prescribed regimen (Farmer, 1999, Valenstein et al., 2002). Overall, it has been estimated that only a third of patients are fully compliant with therapy. Another third are partially compliant, meaning that they will either reduce the dose of the drug prescribed or fail to take drugs from time to time, whilst the final third of patients do not follow prescription instructions at all (Blackwell, 1976, Lima et al., 1976, Wright, 1993).

Poor compliance is not restricted to antipsychotic treatment alone, but is common across all domains of medicine. Perfect compliance is difficult to achieve in most chronic illnesses and is compounded by the need to take continuous medication over an extended period of time. Results from a review on medication compliance in psychiatric patients have shown that patients treated with antidepressants and antipsychotics have similar rates of compliance of between 24–90% and 40–90%, respectively (Cramer and Rosenheck, 1998). Indeed, rates of partial compliance have also been reported in asthma (67% at 20−25 months), diabetes (25% at 6 months), rheumatoid arthritis (67% at 2 years) and hypertension treatment (53% at 6 months) (Sackett et al., 1978, van Wanghe and Dequeker, 1982, Shobhana et al., 1999, Strunk et al., 2002), reflecting the global nature of poor compliance and that it is inherent in human nature. This article provides an overview of the evolution of partial compliance in schizophrenia and its impact on treatment outcomes. In addition, factors that contribute to partial compliance will be highlighted along with a discussion on strategies that may be implemented to improve compliance in patients with schizophrenia.