Background: Increased risk for somatic comorbidity in individuals with schizophrenia has been well established. In addition, psychiatric patients with somatic illnesses are more likely to have more psychiatric readmissions. Increased burden of treatment related to chronic somatic comorbidities may be associated with lower adherence to psychiatric medication.

Methods: Cross-sectional study of 275 patients with schizophrenia spectrum disorder. A general practitioner performed a complete physical health checkup for all participants, including a complete medical examination and laboratory tests. Patients' adherence, attitudes, insight, and side-effects were evaluated using the Attitudes toward Neuroleptic Treatment Scale. Overall symptomatology was measured using the Brief Psychiatric Rating Scale. Regression analysis was used to investigate interactions and associations among health beliefs, disease burden, and treatment adherence. Separate regression models were utilized to account for the complexity of health behavior and treatment adherence pathways.

Results: Patients' somatic comorbidity and health behavior were not associated with adherence or attitudes toward antipsychotic treatment. High dose of antipsychotics and obesity were related to the need for medical interventions, while a healthy diet reduced the risk. Higher BPRS score and older age were associated with having somatic symptoms. Somatic comorbidities had no negative effects on treatment adherence or attitudes.

Conclusion: This study focuses on exploring possible associations between health beliefs and treatment adherence pathways in patients with psychotic disorders. Contrary to our hypotheses, we found no evidence to support our health belief and diseases burden models and their associations.