Treatment adherence rates across different psychiatric disorders and settings: findings from a large patient cohort

Approximately 50% of patients with psychiatric disorders do not fully adhere to the prescribed psychopharmacological therapy, significantly impacting the progression of the disorder and the patient's quality of life. The present study aimed to assess potential differences in terms of rates and clinical features of treatment adherence in a large cohort of psychiatric patients with different diagnoses attending various psychiatric services. The study included 307 psychiatric patients diagnosed with a primary major depressive disorder, bipolar disorder, anxiety disorder, schizophrenic spectrum disorder, or personality disorder. Patient's adherence to treatment was evaluated using the Clinician Rating Scale, with a cutoff of at least five defining adherence subgroups. One-third of the sample reported poor medication adherence. A lower rate of adherence emerged among patients with schizophrenic spectrum disorder and bipolar disorder. Subjects with poor adherence were more frequently inpatients and showed higher current substance use, a greater number of previous hospitalizations, and more severe scores at psychopathological assessment compared with patients with positive adherence. Poor adherence was associated with symptom severity and increased rates of relapses and rehospitalizations. In addition, substance use appears to be an unfavorable transdiagnostic factor for treatment adherence.