Evaluation of Adherence to Pharmacological Treatment in a Large Sample of Patients with Personality Disorder.

Personality disorders (PDs) are chronic and pervasive mental health conditions associated with significant functional impairment and high psychiatric comorbidity. Although psychotherapeutic interventions are the primary treatment approach, pharmacotherapy is frequently prescribed to manage specific symptoms. However, adherence to pharmacological treatment in PDs remains a critical challenge, influenced by both personality traits and clinical factors. The present study aims to assess adherence rates in a large cohort of patients with PDs and explore potential sociodemographic and clinical factors associated with compliance. This observational study included 200 patients diagnosed with PDs according to DSM-5 criteria, recruited from different psychiatric services in Milan, Italy. Adherence was assessed using the Clinician Rating Scale (CRS), with positive adherence defined as CRS ≥ 5 and poor adherence as CRS < 5. Sociodemographic and clinical data were collected and analyzed across adherence groups and PD clusters. Positive adherence was observed in 64.5% of the sample. Cluster C PDs exhibited significantly higher adherence rates (83.3%) compared to Cluster B (61.3%), mixed-feature (60%), and Cluster A (73.3%; p<.05). A positive family history of psychiatric disorders was associated with greater adherence (60.3% vs. 45.5%, p<.05). A trend toward lower adherence was observed in patients with lifetime and current substance use. Higher adherence in Cluster C PDs may be linked to anxiety-driven behavioral patterns, while lower adherence in Cluster B and mixed-feature PDs suggests impulsivity and mistrust contribute to non-compliance. Additionally, a positive family history of psychiatric disorders emerged as a potential protective factor, possibly enhancing treatment engagement through greater awareness and support networks. Future research should focus on developing tailored interventions to the specific needs of different PD clusters to improve long-term treatment outcomes.