Elsevier

Schizophrenia Research

Volume 90, Issues 1–3, February 2007, Pages 229-237
Schizophrenia Research

The use of electronic monitoring (MEMS®) to evaluate antipsychotic compliance in outpatients with schizophrenia

https://doi.org/10.1016/j.schres.2006.11.015Get rights and content

Abstract

Compliance with antipsychotic treatment is a well-recognized concern in the ongoing management of individuals with schizophrenia. The present investigation incorporated the Medication Event Monitoring System (MEMS®) to evaluate compliance in a group of outpatients (N = 52) with schizophrenia or schizoaffective disorder. Evaluating compliance as a dichotomous variable and using a threshold of 80%, the rate of noncompliance as measured by MEMS® was 52%, considerably higher than self-report (3%), clinician rating (24%) and pill count (25%). The ability of treating clinicians to predict compliance/noncompliance was limited: 13 of 31 (42%) subjects they rated as compliant were noncompliant while 4 of 9 (44%) rated as noncompliant were actually compliant according to MEMS®. Factors most consistently associated with noncompliance were higher total symptom scores and dosing complexity i.e., greater than once daily. Based on MEMS® data, the overall mean level of compliance was 66%; however, it remains unclear as to what threshold is associated with a compromise in clinical response. More sophisticated measurement tools such as MEMS® may assist us in better understanding how level and pattern of antipsychotic noncompliance, factors that at present remain poorly understood, impact on symptom exacerbation.

Introduction

Antipsychotic medications represent the cornerstone of treatment programs for individuals with schizophrenia. Unfortunately though, the effectiveness of these drugs is often compromised by noncompliance, a significant factor in both relapse and rehospitalization (Knapp et al., 2004, Robinson et al., 1999, Weiden et al., 2004). While the newer ‘atypical’ antipsychotics have been associated with a number of clinical advantages, including improved tolerability, noncompliance rates remain high (Dolder et al., 2002, Gilmer et al., 2004, Menzin et al., 2003). This is perhaps not so surprising given the evidence that noncompliance is a complex issue, influenced by a number of variables (Fenton et al., 1997, Weiss et al., 2002).

Several factors complicate the study of noncompliance. For example, individuals may not be forthcoming in providing this information, which could contribute to the wide range in estimates reported for compliance with antipsychotic treatment (Young et al., 1986). Different strategies have been used to improve accuracy of reporting (e.g., biologic markers, pill count), each with their own limitations (Blackwell, 1989, Cramer and Rosenheck, 1998). More recently, efforts to provide greater objectivity in measuring noncompliance have led to the development of electronic monitoring devices such as the Medication Event Monitoring System ([MEMS®], Aprex Corp., Fremont, Calif.), a medication bottle cap with a microprocessor that records the occurrence and time of each bottle opening (Cramer et al., 1989, Kruse and Weber, 1990). Considered by many to be the gold standard in evaluating compliance, these devices have been used in the study of various psychiatric and medical disorders (Bies et al., 2002, Bova et al., 2005, de Klerk, 2001, Leopold et al., 2004, McKenney et al., 1992, Shemesh, 2004).

There are now a small number of published reports that have used MEMS® in individuals with schizophrenia or schizoaffective disorder (Byerly et al., 2005, Diaz et al., 2001, Diaz et al., 2004, Nakonezny and Byerly, 2006). One report linked poor compliance (i.e., less than 50%), with increased hospitalization rates (Diaz et al., 2001), while a second study employing MEMS® demonstrated that clinicians dramatically underestimate compliance (Byerly et al., 2005). Two investigations using MEMS® have reported comparable compliance rates for typical and atypical antipsychotics (Diaz et al., 2004, Nakonezny and Byerly, 2006). Drawing upon the existing literature on compliance, our objectives were twofold. First, we were interested in comparing rates of compliance/noncompliance, as measured by MEMS® versus other evaluation techniques (e.g., self-report, clinician rating, pill count). Second, we wanted to examine the relationship between compliance/noncompliance, defined here by the MEMS® data, and various factors that have been identified as influencing compliance (e.g., side effects, insight).

Section snippets

Subjects

Patients were recruited from the Schizophrenia Program at the Centre for Addiction and Mental Health, a teaching hospital affiliated with the University of Toronto, Toronto, Canada. The program employs a case management system and follows several thousand individuals in both inpatient and outpatient settings. The study was approved by the Research and Ethics committee of the university.

Psychiatrists in the program provided study referrals, and inclusion criteria included the following: a)

Results

A total of 60 potential subjects were evaluated, of which 53 agreed to participate. One did not return the medication bottle with the MEMS® cap at follow-up and was subsequently excluded from the data analysis. Demographic data for the study sample (N = 52) were as follows: 26 males, 26 females; age (mean, SD) 36 ±10.3 years (range 19–55); education 13.2 ± 2.2 years (range 9–18); marital status — single (89%), married (11%); diagnosis — schizophrenia (67%), schizoaffective (33%); length of illness

Discussion

Using MEMS®, noncompliance with antipsychotic medication was 52% when viewed as a dichotomous variable, in line with a reported value of 48% in the one other study that used a threshold approach (in their case, 70%) to evaluate a somewhat similar population (Byerly et al., 2005), but in marked contrast to the 3% reflecting self-report or even the 22% estimated by the treating clinicians in our sample. The discrepancy between self-report and clinician estimates of compliance has been reported

Acknowlegments

We gratefully acknowledge the patients for their participation in this project.

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