Treatment Adherence

Overview

Poor adherence to psychiatric treatments is a widespread clinical problem that negatively impacts rates of treatment response and remission. While empirically-supported treatments are available for many psychiatric disorders, these treatments are not universally effective. Patients commonly face diffi­culties in taking prescribed psychotropic medications or attending psychotherapy sessions as recommended, and therefore may not achieve optimal outcomes. Moreover, some patients who adhere to treatment recommendations may not experience a clinically significant response, and this often leads them to remain in care and to tolerate treatment plan modifications.

The World Health Organization has defined adherence as the extent to which patients' health behaviors are consistent with recommendations that they have agreed to with their practitioners. This definition emphasizes that practitioners must collaborate with their patients in making decisions throughout treatment. However, researchers frequently evaluate patient adherence to psychiatric regimens in ways which do not capture the dynamics among patients, practitioners, and health care systems. Common measures include the extent to which patients take their medications at the prescribed dose and timing, attend scheduled clinic appointments, and remain in care. These broad measures are discussed in this chapter (summarizing findings on the prevalence of, and the barriers to, psychiatric treatment adherence). This chapter also highlights the fact that optimal adherence is a moving target that involves complex patient behaviors and multi-factorial challenges, and may be enhanced by targeted strategies for patients, practitioners, and systems.

Epidemiology of Adherence

The estimated prevalence of patient adherence to the use of psychotropic medications has varied widely, due to differences in study populations, diagnoses, medication classes, and the definition of adherence. However, evidence strongly supports the notion that poor adherence is common across groups. Substantial proportions of community-dwelling patients take less than their prescribed daily doses of antipsychotics (34.6%), sedative-hypnotics (34.7%), anxiolytics (38.1%), mood stabilizers (44.9%) and antidepressants (45.9%). In a retrospective study of managed care patients, approximately 57% of patients who had started a selective serotonin re-uptake inhibitor (SSRI) for depression and/or anxiety were not adherent to the medication. In fact, many patients with depression (19%–28%) also do not show for scheduled clinic appointments.

Reports of adherence to taking psychotropic medications further reflect problems with premature treatment discontinuation. Moreover, many patients do not inform their physician about having stopped their medication. Across studies of treatment trials for anxiety disorders (generally lasting 10–12 weeks), 18%–30% of patients discontinued their treatment prematurely. Among patients with depression who were taking an SSRI, almost half (47%) had stopped filling their prescription within 2 months of treatment initiation. Similarly, a pooled analysis of 1,627 patients with psychosis treated with atypical antipsychotics revealed that about half (53%) of the patients discontinued their medication soon after treatment began. Researchers in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) reported that almost three-fourths (74%) of patients with chronic schizophrenia discontinued treatment within 4 months of its initiation.

Some studies have shown that adults with depression prefer psychotherapy over antidepressants. Yet, in a sample of primary care patients with depression, 74% endorsed that barriers to care made it very difficult or impossible to attend regular psychotherapy sessions. Meta-analyses of cognitive-behavioral therapy (CBT) trials for anxiety disorders indicated that for patients who started CBT, between 9% and 21% discontinued the treatment early.

Clinical and Economic Impact of Non-Adherence

Poor adherence to psychiatric treatments leads to worse clinical outcomes and to excess health care utilization; these factors contribute, in turn, to the economic burden of mental illness. Among patients with depression, non-adherence to antidepressants is associated with higher medical costs and accounts for 5%–40% of hospital readmissions. Medication non-adherence also is the most powerful predictor of relapse after a first episode of schizophrenia, independent of gender, age of onset, premorbid function, patient insight, or other key factors. Moreover, non-adherent patients with schizophrenia are at greater risk for substance use, violence, and victimization, as well as worse overall quality of life. Although little studied, patient non-adherence also may increase the risk of burnout and fatigue among psychiatric practitioners. Findings emphasize that intervening at multiple levels to enhance adherence has the potential to improve population health and well-being and to reduce excess health care utilization, beyond individual improvements in specific treatments.

Risk Factors for Non-Adherence

Risk factors for non-adherence are complex and varied, and remain incompletely understood. Findings are typically drawn from secondary analyses or exit interviews from randomized controlled trials (RCTs), which employ strict eligibility criteria and rigorous patient monitoring. In clinical settings, practitioners must consider and address multi-factorial challenges to optimal patient adherence ( Table 2-1 ). Key risk factors are summarized below.