Imperial Journal of Interdisciplinary Research (IJIR) Vol-2, Issue-9, 2016 ISSN: 2454-1362, http://www.onlinejournal.in Imperial Journal of Interdisciplinary Research (IJIR) Page 1028 Somatotype in Bipolar Disorder Revisited: Gender Differences, Neurodevelopment and Clinical Implications Mladen Mantarkov 1* , Ferihan Ahmed-Popova 2 , Valentin Akabaliev 1 Stefan Sivkov 2 1 Department of Psychiatry and Medical Psychology, Medical University of Plovdiv, Bulgaria 2 Department of Anatomy, Histology and Embryology, Medical University of Plovdiv, Bulgaria Abstract: Ninety-five years after Kretschmer’s original publication the concept of somatotype in psychiatry remains controversial. The aim of the current study was to compare the somatotype of patients with bipolar I disorder and sex-matched mentally healthy controls using an objective method of somatotyping and predefined inclusion and exclusion criteria. 67 bipolar I patients (26 males, 41 females) and 119 mentally healthy controls (54 males, 65 females) were assessed using the Heath-Carter Anthropometric Method. Bipolar I males were significantly less endomorphic and more ectomorphic than sex- matched controls. Bipolar I females were significantly less ectomorphic than sex-matched controls. We found significant interaction effects between gender and group membership on all somatotype components. Bipolar I males had significantly lower, while bipolar I females had significantly higher BMIs than controls. Kretschmer’s hypothesis may only apply to females. In an age of orexigenic mood stabilizers bipolar I females may be a particularly vulnerable treatment population. Our data suggest bipolar I disorder has neurodevelopmental underpinnings. Key words: Bipolar disorder, Somatotype, Neurodevelopment, Gender differences, Sexual dimorphism, Body mass index, Central obesity, Mood stabilizers. 1. Introduction Ninety-five years ago, on the basis of direct visual observation, Ernst Kretschmer described three major body types: asthenic, athletic and pyknic, that could influence behavior and susceptibility to mental illness, particularly to manic-depressive disorder and schizophrenia [1,2]. Kretschmer believed that every single individual could be characterized as either asthenic, athletic, pyknic or dysplastic (a category, he recognized a little later). In Kretschmer’s view, pyknic individuals were of cyclothymic temperament and more susceptible to bipolar disorder, while asthenic individuals were of schizoid temperament and more susceptible to schizophrenia [2-4]. Five different studies published in the 1920’s and 1940’s lent partial support to Kretschmer’s observations [5,6]. The authors found a correlation between schizophrenia and the asthenic body build and between manic-depressive disorder and the pyknic body build. Although Kretschmer has been widely criticized for the purely observational nature of his studies and his small sample sizes, his influence on the constitutional approach in psychiatry over the last century remains undoubted [6]. Over a decade after Kretschmer’s original publication, William Sheldon revolutionized the constitutional approach to the study of human physique and behavior in several different ways [6]. He was the first to use the term somatotype and to define its three main components: endomorphy (predominance of the width in relation to height, or relative obesity), mesomorphy (musculoskeletal predominance, including the internal fat mass, internal organs and total body fluids) and ectomorphy (overall linearity of the body): all irrespective of body size [3,6,7]. Sheldon presumed that the cells that contributed to the formation of the components of the somatotype derived from the respective germ layers (the endoderm, mesoderm and ectoderm), so in his view the somatotype was inborn and therefore immutable throughout life. Sheldon’s perhaps most important contribution to the study of human physique was that he adopted a dimensional model in which every component of the somatotype could be evaluated on a 1 to 7 scale. Sheldon used the photoscopic method for somatotyping, in which the somatotype components are calculated using various anthropometrical measurements in conjunction with standardized photos. Years later, his student