Study Objectives: Continuous positive airway pressure (CPAP) improves sleep and quality of life for both patients with obstructive sleep apnea (OSA) and their spouses. However, few studies have investigated spousal involvement in treatment adherence. Aims of this observational study were to assess perceptions of spousal involvement and evaluate associations between involvement and adherence. Methods: Spousal involvement in CPAP adherence was assessed in 23 married male OSA patients after the fi rst week of treatment. At 3 months, 16 participants completed a second assessment of spousal involvement. Types of involvement assessed included positive (e.g., encouraging), negative (e.g., blaming), collaboration (e.g., working together), and onesided (e.g., asking). An interpersonal measure of supportive behaviors was also administered at 3 months to evaluate the interpersonal qualities of spousal involvement types. Objective CPAP adherence data were available for 14 participants. Results: Average frequency of spousal involvement ratings were low for each involvement type and only negative spousal involvement frequency decreased at 3 month follow-up (p = 0.003). Perceptions of collaborative spousal involvement were associated with higher CPAP adherence at 3 months (r = 0.75, p = 0.002). Positive, negative and one-sided involvement were not associated with adherence. Collaborative spousal involvement was associated with moderately warm and controlling interpersonal behaviors (affi liation, r = 0.55, p = 0.03, dominance r = 0.47, p = 0.07). Conclusions: Patients reported low frequency but consistent and diverse perceptions of spousal involvement in CPAP over the fi rst 3 months of treatment. Perceptions of collaborative spousal involvement were the only type associated with adherence and represent moderately warm and controlling interpersonal behavior. Interventions to increase spousal collaboration in CPAP may improve adherence. keywords: Obstructive sleep apnea, continuous positive airway pressure, adherence, relationship quality, social support Citation: Baron KG; Gunn HE; Czajkowski LA; Smith TW; Jones CR. Spousal involvement in CPAP: does pressure help?