Definition of Psychosomatic Medicine and the Applicability of DSM-IV-TR to Outpatients Visiting a Japanese Psychosomatic Clinic
Authors: Mutsuhiro Nakao, Takeaki Takeuchi, Gregory Fricchione
Journal: Psychotherapy and Psychosomatics (2014)

The Japanese Society of Psychosomatic Medicine defines psychosomatic illness as any physical condition involving organic or functional damage that is affected by psychological factors in the process of its onset or development [1]. This definition largely corresponds to that of 'psychological factors affecting medical conditions' (code 316), which appears in the Diagnostic and Statistical Manual of Mental Disorders, ed 4, text revision (DSM-IV-TR) published by the American Psychiatric Association [2]. A variety of patients visit psychosomatic clinics, ranging from those with medically unexplained symptoms related to psychophysiological or somatoform disorders to those with specific psychiatric disorders, conditions co-existing with somatic symptoms. In the present study, we systematically classified a group comprised of patients requiring treatment from a psychosomatic medicine perspective, including those with somatoform disorders, as well as a group of patients with other psychiatric disorders, including depressive and anxiety disorders, using DSM-IV-TR axis I diagnoses.The psychosomatic outpatient clinic is located in Teikyo University Hospital, a tertiary-care, university-affiliated hospital in a Japanese metropolis [3]. The psychosomatic outpatient clinic was established in 2001 and is operated by two full-time staff members (a professor and an assistant professor) and one part-time staff member. New outpatients are asked to bring referrals from other departments in the hospital as well as from other hospitals or clinics in the metropolitan area, but those without referrals can visit the clinic for a fee of 5,000 JPY. The subjects were 1,023 outpatients who visited the psychosomatic outpatient clinic for the first time between January 2002 and December 2012. Their mean age was 45.9 years, and females made up 65.4% of the sample. Major somatic symptoms were fatigue (48.4%), insomnia (36.3%), low back pain (31.5%), headache (28.8%), palpitation (26.9%), shortness of breath (24.0%), constipation (22.2%), and dizziness (22.0%). Among all patients, 445 were referred from departments within the hospital, 177 were referred from outside the hospital, and the remaining 401 visited the clinic without referral. Based on our previous study [4], semi-structured interviews were conducted by physicians with all patients during their first visit to assess DSM-IV-TR axis I diagnoses. The results were coded and recorded in the database. The patients were categorised into four groups: psychosomatic, depression, anxiety, and other. The psychosomatic group included those with psychological factors affecting medical conditions (316) and somatoform disorders (300.11, 300.7, 300.81, 300.82, and 307.XX). The depression group included those with mood disorders (293.83, 296.XX, 300.4, 301.13, and 311). The anxiety group included those with anxiety disorders (293.84, 300.00, 300.01, 300.02, 300.21, 300.22, 300.23, 300.29, 300.3, 308.3, and 309.81). The other group included those with other DSM-IV-TR axis I codes, such as dementia (294) and schizophrenia (295). A detailed manual of diagnoses was created [4], and all three physicians in the clinic discussed the patients' diagnoses once per week to improve reliability. All tests of statistical significance were interpreted with a two-tailed criterion of p < 0.05. General linear models were used for group comparisons, controlling for the effects of age and sex. Statistical analyses were performed using the SAS statistical package [5]. This study was approved by the Human Subjects Committee at our hospital and conducted after obtaining written informed consent from participants.As shown in table 1, the most frequent diagnosis was somatoform disorders not otherwise specified (NOS), followed by major depressive disorder, depressive disorder NOS, psychological factors affecting medical conditions, general anxiety disorder, sleep disorder, and panic disorder without agoraphobia (>5%). The psychosomatic group included 37% of all patients. Individuals in the psychosomatic group were most likely to have been referred from within the hospital (45%), the second largest subgroup received referrals from outside the hospital (37%), and the smallest subgroup presented without a referral (27%). Among patients in the psychosomatic group, a significantly higher percentage was referred from within the hospital than from outside the hospital or not referred (all p < 0.05). A significantly higher percentage of patients in this group also comprised those referred from outside the hospital compared with those without referrals (p < 0.05).This study examined the applicability of DSM-IV-TR axis I diagnoses to outpatients who visited the psychosomatic clinic, and the psychosomatic group comprised <40% of all patients. The depression and anxiety groups each comprised >20% of the patients. These results were compatible with our clinical experience that depressed or anxious patients often visit the psychosomatic clinic complaining of somatic symptoms that may mask depressive and anxiety disorders. Additionally, chronic physical disorders can affect the course of depressive and anxiety disorders [6]. It is clinically important to understand that patients experience their symptoms as intense and disturbing and to consider the possibility that such symptoms mask depression and other psychiatric disorders. Notably, those without referrals were significantly less likely to be categorised into the psychosomatic group, suggesting that consultation with a primary care physician could facilitate appropriate care at the psychosomatic clinic [7]. Those referred from outside the hospital were significantly less likely to be categorised into the psychosomatic group than were those referred from inside the hospital, but they were relatively more likely to be categorised into the psychosomatic group than were those without any type of referral. Adequate understanding of psychosomatic medicine by primary care physicians is also important with regard to increasing appropriate referrals to psychosomatic medicine clinics. More specifically, the most frequent DSM-IV-TR diagnosis was somatoform disorders NOS. This diagnosis is given when a patient experiences various somatoform disorder symptoms but does not fully meet the diagnostic criteria for any particular disorder [2]. The anticipated changes in the nomenclature for somatoform patients in DSM-5 include the addition of positive psychological diagnostic criteria, which cover excessive thoughts, feelings, and behaviours related to somatic symptoms or associated health concerns [8]. Psychosomatic medicine is regarded as a comprehensive interdisciplinary framework for assessing psychological factors affecting individual vulnerability to the course and outcome of any type of disease [9]. Future research should establish a diagnostic framework for assessing the holistic aspects of somatoform disorders or somatic symptoms disorders, including behavioural and psychological problems associated with somatic complaints [10].