Introduction

Treatment adherencehas been examined from various scientific perspectives and it has an important influence on treatment effectiveness. There is confusion about the conceptual and operational definitions of treatment adherence. In part, this may be attributed to the multitude of terms that have often been used interchangeably to refer to this concept. For example, compliance, cooperation, concordance, mutuality,and therapeutic alliancehave been used, and operational definitions of these terms vary widely across studies (1). Most definitions contain elements relating to patients' self-care responsibilities, their role in the treatment process, and their collaboration with health care providers.