In recent years, there has been increased interest in a clinical syndrome characterized by excessive sexual thoughts, sexual urges, and/or sexual behaviors that has many aspects in common with impulse control disorders. This study provides a preliminary examination of the impulsive aspects of this syndrome, compulsive sexual behavior (CSB). Sixteen male subjects, eight CSB patients and eight non-patient controls, completed psychometric measures of impulsivity and compulsive sexual behavior, performed a behavioral task designed to assess impulse control (Go–No Go task), and underwent diffusion tensor imaging (DTI) procedures. The results indicated that CSB patients were significantly more impulsive; whether measured by psychometric testing or the Go-No Go procedure, than controls. The results also indicate that CSB patients showed significantly higher superior frontal region mean diffusivity (MD) than controls. A correlational analysis indicated significant associations between impulsivity measures and inferior frontal region fractional anisotropy (FA) and MD, but no associations with superior frontal region measures. Similar analyses indicated a significant negative association between superior frontal lobe MD and the Compulsive Sexual Behavior Inventory. Thus, while CSB patients were more impulsive than controls, the DTI results were not consistent with impulse control disorders.
Over the course of the last several decades, an increasing number of clinicians and researchers have become interested in a clinical syndrome involving excessive sexual thoughts, sexual urges, or sexual activity which cause distress or impairment. This phenomenon has been called compulsive sexual behavior (CSB; Quadland, 1985 and Coleman, 1991), paraphilia-related disorder (Kafka, 1994), sexual impulsivity (Barth and Kinder, 1987), and sexual addiction (Carnes, 1983 and Goodman, 1993). Coleman and colleagues (Coleman et al., 2000) proposed criteria for CSB that require the presence of recurrent and intense sexually arousing fantasies, sexual urges, or behaviors over a period of at least 6 months that cause distress or impairment. While there are some disagreements over the nature and the etiology of compulsive sexual behavior, all of the researchers listed above agree that the syndrome includes intense, intrusive sexual urges and fantasies, along with excessive problematic sexual behavior. In this manner, CSB resembles impulse control disorders such as kleptomania, pathological gambling, and eating disorders such as bulimia nervosa and binge eating disorder.
Although there have been no brain-imaging studies of CSB, it has been suggested that damage to the frontal lobes can result in disinhibition of sexual behavior, and thus, hypersexual, or CSB (Coleman, 2005). Diffusion tensor imaging (DTI) is an MRI technique that measures the self-diffusion of water in brain tissue. DTI has been used to provide quantitative information about white matter organization and integrity. The DTI data can be represented in a number of ways, including fractional anisotropy (FA), a measure of the extent to which water diffusion is directionally restricted, and mean diffusivity (MD), a measure of overall diffusivity in the tissue. Grant et al. (2006) used DTI to examine white matter in kleptomania. These investigators found that FA was significantly lower in the inferior frontal regions of individuals with kleptomania, indicating altered white matter organization in this region of the brain, which influences executive function and inhibitory control (Hoptman et al., 2002).
The purpose of this study is to explore white matter micro-structure with DTI in men with CSB. Given the results for kleptomania and the presence of impulsivity in CSB, we hypothesized that we would find greater disorganization of white matter on DTI in the frontal lobes of men with CSB and that this white matter disorganization would be associated with greater impulsivity in CSB patients than non-CSB controls.
