Study objective: To compare the MMPI responses between nonapneic primary snoring (PS) and obstructive sleep apnea (OSA).
Design: Cross sectional with matched samples.
Setting: University sleep disorders center.
Patients: All PS patients (n = 49) available in a series of 428 clinical referrals to a sleep disorders center, and age and gender-matched OSA patients (n = 49) selected from the 199 available OSA patients in the series.
Interventions: Not applicable.
Measurements and results: Subjects completed the MMPI prior to overnight diagnostic polysomnographic assessment and multiple sleep latency test (MSLT). OSA patients exhibited a mean of 2.3 elevated MMPI scales, which was significantly more than the PS mean of 1.6 elevations, and attributable to higher OSA scores on Depression (D) and Hypochondriasis (Hs). Approximately twice as many OSA patients than PS patients showed disturbed scores on D (49% vs. 25%, p < .05) and Hy (35% vs. 16%, p < .05). On nine of the ten MMPI clinical scales, both patient groups exceeded the elevation rate expected in nondistressed individuals. Among OSA patients, but not PS patients, number of MMPI elevations had a significant negative correlation with sleep efficiency and average blood saturation during NREM, and a significant positive correlation with wake time after sleep onset.
Conclusions: Compared to patients with PS, those with OSA have more intense depressive symptoms (e.g., pessimism, inactivity, guilt) and somatic concerns. General psychopathology is associated with blood oxygen saturation only among OSA patients. Nonetheless, PS patients show psychological maladjustment that is qualitatively similar, but quantitatively less severe, than that characterizing OSA.