Adherence and Effectiveness of Positive Airways Pressure (PAP) Therapy in Obstructive Sleep Apnea (OSA) Patients Suffering from Mental Disorders

<b>Objectives:</b> Obstructive sleep apnea (OSA) is a common and serious disorder associated with significant health risks. Individuals with mental disorders exhibit a higher prevalence of OSA and may encounter unique challenges in adhering to positive airway pressure (PAP) therapy. However, evidence on long-term adherence and treatment outcomes in this population remain limited. This study aimed to evaluate PAP therapy adherence and effectiveness in adults with moderate-to-severe OSA, comparing individuals with comorbid mental disorders to those without psychiatric diagnoses over a three-year follow-up period. <b>Methods:</b> A prospective observational cohort study was conducted at a tertiary academic center, enrolling 1672 adults newly diagnosed with moderate-to-severe OSA. Participants were grouped into those with (n = 221) and without (n = 1451) comorbid mental disorders. Clinical, anthropometric, and sleep parameters, including Epworth Sleepiness Scale (ESS) scores and PAP usage, were assessed at baseline and at five follow-up visits over three years. Adherence was defined as average nightly PAP use, and effectiveness was evaluated by changes in ESS, BMI, blood pressure, and heart rate. Longitudinal trends were analyzed using linear mixed-effects models. <b>Results:</b> Patients with mental disorders demonstrated comparable or slightly higher PAP adherence throughout the follow-up, with numerically greater average nightly usage at each time point. Although between-group differences were not statistically significant, linear mixed effects modeling confirmed stable PAP adherence over time in both groups (Group A: F (4, 12.79) = 0.184, <i>p</i> = 0.942; Group B: F (4, 150.11) = 1.102, <i>p</i> = 0.358). Daytime sleepiness, measured by ESS, improved significantly over time in both groups (Group A: F (5, 14.29) = 4.619, <i>p</i> = 0.010; Group B: F (5, 60.39) = 29.52, <i>p</i> < 0.001). Notably, by the final follow-up, patients with mental disorders reported lower ESS scores than those without (3.67 vs. 6.00), indicating meaningful clinical improvement. <b>Conclusions:</b> PAP therapy is both feasible and effective in patients with stable mental disorders. The presence of psychiatric comorbidity does not impede adherence and may even enhance long-term engagement when supported by integrated, multidisciplinary care.