Original article The psychological aspects of patients with delayed sleep phase syndrome (DSPS) Masako Shirayama a,c , Yukihiko Shirayama a, * , Hideharu Iida a , Masaaki Kato a , Naofumi Kajimura a , Tsuyoshi Watanabe a , Masanori Sekimoto a , Shuichiro Shirakawa b , Masako Okawa b , Kiyohisa Takahashi a a Department of Psychiatry, National Center Hospital for Mental, Nervous and Muscular Disorders, National Center of Neurology and Psychiatry, Kodaira, Japan b Department of Psychophysiology, National Institute of Mental Health, National Center of Neurology and Psychiatry, Ichikawa, Japan c Kawasaki Mental Clinic, Taitoh, Japan Received 11 February 2003; received in revised form 11 March 2003; accepted 17 April 2003 Abstract Objective: The current study attempts to define the psychological features of patients with delayed sleep-phase syndrome (DSPS). Method: We administered the Yatabe – Guilford test (Y – G test), Minnesota Multiphasic Personality Inventory (MMPI), Picture- Frustration study (P-F study) and Rorschach test to two groups, one of patients with DSPS (case group) and the other of people without psychiatric symptoms or insomnia (control group). Results: Overall, the results of the tests indicate that patients with DSPS showed emotional features such as nervousness, depression and lack of control of emotional expression. Specific personality traits included introspection, defensiveness, aspiration for intellectual attainment with compulsivity, overly abstract thinking, unawareness of impulsivity to immediate gratification, perseverance and reduced cognitive ability. In addition, the patients with DSPS showed psychopathological features similar to those of neurosis, hypochondriasis, depression, conversion hysteria and psychopathic deviate. Conclusions: There seems to exist a definite psychological profile for patients with DSPS. (1) an excessive defense mechanism that increases nervousness and develops neurosis; (2) a high level of intellectual aspiration with compulsivity that makes the patients feel self- defeated, powerless and disappointed; (3) a tendency to egocentric emotion, inhibition and perseverance. These characteristics may worsen social withdrawal, causing a loss of social cues in synchronizing their circadian rhythm. Thus, the phase shift becomes more difficult and a vicious circle is constituted. q 2003 Elsevier B.V. All rights reserved. Keywords: Delayed sleep-phase syndrome (DSPS); Neurosis; Depression; Minnesota Multiphasic Personality Inventory (MMPI) 1. Introduction Patients diagnosed with delayed sleep phase syndrome (DSPS) have difficulty awaking at a desirable time in the morning and adapting socially. Weitzman et al. first defined DSPS in 1981 [1]. One hypothesis about its cause states that it is produced by a chronobiological dysfunction. For example, it has been reported that chronobiological interventions such as bright light therapy [2,3] and administration of vitamin B 12 [4,5] and melatonin [6,7] are effective against sleep-onset insomnia in patients with DSPS. Conventional hypnotic drugs and antidepressants have also been used in the treatment of DSPS [8]. Psychotherapy has been used to treat patients with DSPS because they are often frustrated with their inability to adhere to regular work and social schedules and present with various psychosocial complaints. The psychological profile of patients with DSPS has been partially described. Previous studies have reported that psychometric signs of depression and hypochondriasis are present in these patients [9,10]. However, another study reported that it is unlikely 1389-9457/03/$ - see front matter q 2003 Elsevier B.V. All rights reserved. doi:10.1016/S1389-9457(03)00101-1 Sleep Medicine 4 (2003) 427–433 www.elsevier.com/locate/sleep * Corresponding author. Department of Neuropsychiatry, Faculty of Medicine, Tottori University, 36-1 Nishi-machi, Yonago, Tottori 683-8504, Japan. Tel.: þ 81-859-34-8107; fax: þ81-859-34-8097. E-mail address: shirayama@rapid.ocn.ne.jp (Y. Shirayama).