Background: Maintaining antipsychotic therapy in psychosis is important in preventing relapse. Long-acting depot preparations can prevent covert non-adherence and thus potentially contribute to better patient outcomes. In this observational survey the main objective is to evaluate medication adherence and its determinants for oral treatment in a large sample of patients with psychosis.
Methods: In this cross-sectional survey medication adherence for oral treatment was assessed by patients using the patient-rated Medication Adherence Questionnaire (MAQ). Data were collected by physicians on patients with a recent acute psychotic episode before switching to long-acting injectable risperidone. Other evaluations included disease severity (Clinical Global Impression - Severity), patients' insight (Positive and Negative Syndrome Scale item G12), treatment acceptance (clinician-rated Compliance Rating Scale), and therapeutic alliance (patient-rated 4-Point ordinal Alliance Scale).
Results: A total of 399 psychiatrists enrolled 1,887 patients (mean age 36.8±11.9 years; 61.6% had schizophrenia). Adherence to oral medication was "low" in 53.2% of patients, "medium" in 29.5%, and "high" in 17.3%. Of patients with psychiatrist-rated active acceptance of treatment, 70% had "medium" or "high" MAQ scores (P<0.0001). Medication adherence was significantly associated with therapeutic alliance (4-Point ordinal Alliance Scale score; P<0.0001). Patient age was significantly associated with adherence: mean age increased with greater adherence (35.6, 36.7, and 38.6 years for patients with "low", "medium", and "high" levels of adherence, respectively; P=0.0007), while age <40 years was associated with "low" MAQ classification (P=0.0003). Poor adherence was also associated with a diagnosis of schizophrenia (P=0.0083), more severe disease (Clinical Global Impression - Severity ≥4; P<0.0001), and lower insight (Positive and Negative Syndrome Scale-G12 ≥4; P<0.0001).
Conclusion: Self-reported adherence was low in most patients, with a strong positive association between self-reported adherence and psychiatrists' assessment of treatment acceptance. Understanding factors associated with poor medication adherence may help physicians to better manage their patients, thereby improving outcomes.
Keywords: long-acting antipsychotic; medication adherence; schizophrenia; therapeutic alliance.