BACKGROUND:Obstructive sleep apnea (OSA) is prevalent among bariatric surgery candidates and is associated with numerous adverse health conditions, both pre- and postoperatively. Continuous positive airway pressure therapy (CPAP) is the first-line treatment for OSA, but it requires significant behavioral changes. As such, CPAP adherence is a significant problem in OSA treatment. Information from the preoperative psychological evaluation may be used to identify psychosocial risk factors associated with CPAP nonadherence and inform the implementation of more specific and appropriate interventions. OBJECTIVES:Examine the utility of Minnesota Multiphasic Personality Inventory-2-Restructured Form (MMPI-2-RF) behavioral/externalizing dysfunction scale scores to determine personality and psychopathology associations with, and risk for, CPAP nonadherence. SETTING:Academic medical center. METHODS:Patients who underwent a preoperative psychological evaluation and were diagnosed with OSA (n = 358) were divided into 2 groups: CPAP adherent (n = 271) and CPAP nonadherent (n = 87). Independent samples t tests were computed to examine differences in average MMPI-2-RF scale scores between these groups. Relative risk ratios were computed using multiple MMPI-2-RF substantive scale score cut-offs to determine which MMPI-2-RF scales were associated with increased risk of CPAP nonadherence. RESULTS:Higher scores on scales measuring behavioral/externalizing dysfunction and family problems were associated with and indicative of risk for CPAP nonadherence. CONCLUSIONS:CPAP nonadherence is related to and may be affected by generally higher levels of behavioral/externalizing dysfunction. Using a broadband measure of personality and psychopathology, like the MMPI-2-RF, during the preoperative evaluation can provide important information about co-morbid symptoms that may interfere with CPAP adherence. Considering this information during preoperative treatment planning could increase the likelihood of preoperative CPAP adherence and reduce the likelihood of adverse postoperative outcomes.