Personality profiles in paradoxical insomnia: a case-control study

Introduction Paradoxical insomnia (PARA-I) is a clinically challenging condition to diagnose and treat. Previous findings suggest that personality profiles of patients with PARA-I may be different from other subtypes of insomnia. Therefore, investigation of these profiles can be helpful in the clinical management of these patients. Objective The current study compares personality profiles of individuals with paradoxical insomnia (PARA-I), psycho-physiological insomnia (PSY-I), and normal sleepers (NS). Material and Methods A cross-sectional case-control study was conducted in the Sleep Disorders Research Center of Kermanshah University of Medical Sciences, Kermanshah, Iran between 2015 and 2017. Patients with PARA-I (n=20), PSY-I (n=20), and NS (n=60) were matched for age, gender, education, and history of mental and/or physical illness and completed the Minnesota Multiphasic Personality Inventory (MMPI) short form. One-way analysis of variance (ANOVA) and the Kruskal-Wallis test were used to compare subscale means across groups. Results With the exception of the schizophrenia scale (P =.059), significant differences were found in all subscales of the insomnia groups compared to the NS group (P=.001). Compared to the NS group, patients with PARA-I showed significant differences in the hysteria and hypomania subscales (P<.05) and patients with PSY-I showed significant differences in the hysteria, hypochondriasis, and psychopathic subscales (P=.001). No significant differences were found between the PARA-I and PSY-I groups on any subscale. Conclusion This study demonstrates that significant differences in the personality profiles on the MMPI exist between PARA-I and PSY-I patients compared to NS. These findings should inform the diagnosis and future treatment approaches for insomnia.