Differential rates of psychopathology symptoms in periodic limb movement disorder, obstructive sleep apnea, psychophysiological insomnia, and insomnia with psychiatric disorder

Study Objective: To determine patterns and relative intensity of psychopath ology, as measured by the Minnesota Multiphasic Personality Inventory (MMPI ), in 108 patients with either psychophysiological insomnia (PI; n=20), ins omnia with psychiatric disorder (IPD; n=30), periodic limb movement disorde r (PLM; n=28), or obstructive sleep apnea (OSA; n=30). Design: Cross-sectional. Setting: University sleep disorders center. Measurements and Results: Subjects completed the MMPI prior to overnight di agnostic polysomnographic assessment followed by Multiple Sleep Latency Tes t (MSLT). Seventy five percent of the entire sample had at least one MMPI e levation (T>70). Groups showed significant baseline differences in age, BMI , and MSLT latency (all ps<.05). Logistic regression indicated that even af ter statistically controlling for these three diagnostic covariates, MMPI e levation was more likely among PLM and IPD patients than OSA or PI patients (all ps<.05). Followup pairwise comparisons indicated that this same patte rn of group differences occurred for the Depression, Psychasthenia, and Sch izophrenia scales (all ps<.05). Conclusions: Irrespective of age, obesity, and daytime sleepiness, patients with untreated PLM or IPD are more likely to experience clinically signifi cant psychological difficulties than those with either OSA or PI. These dif ferences are most likely to be manifested in terms of depressive symptoms, anxiety symptoms (tension, worry guilt), social alienation, and diminished mental concentration. Finally, PLM may be associated with greater MMPI elev ations than previously suspected, and agree with earlier clinical reports o f high rates of psychiatric treatment in PLM.