Compulsive sexual behaviour as a behavioural addiction: the impact of the internet and other issuesThe issue of sex addiction as a behavioural addiction has been much debated. However, there is little face validity for co-occurring behavioural addictions, and more emphasis is needed on the characteristics of the internet as these may facilitate problematic sexual behaviour.The review by Kraus and colleagues [1] examining the empirical evidence base for classifying compulsive sexual behaviour (CSB) as a behavioural (i.e. non-substance) addiction raises many important issues and highlights many of the problems in the area, including the problems in defining CSB, and the lack of robust data from many different perspectives (epidemiological, longitudinal, neuropsychological, neurobiological, genetic, etc.). I have carried out empirical research into many different behavioural addictions (gambling, video-gaming, internet use, exercise, sex, work, etc.) and have argued that some types of problematic sexual behaviour can be classed as sex addiction, depending upon the definition of addiction used [2][3][4][5].However, there are areas in Kraus et al.'s paper that were mentioned briefly without any critical evaluation. For instance, in the section on co-occurring psychopathology and CSB, reference is made to studies claiming that 4-20% of individuals with CSB also display disordered gambling behaviour. A comprehensive review [5] examining 11 different potentially addictive behaviours also highlighted studies claiming that sex addiction could co-occur with exercise addiction (8-12%), work addiction (28-34%) and shopping addiction (5-31%). While it is possible for an individual to be addicted to (for instance) cocaine and sex concurrently (because both behaviours can be carried out simultaneously), there is little face validity that an individual could have two or more co-occurring behavioural addictions because genuine behavioural addictions consume large amounts of time every day. My own view is that it is almost impossible for someone to be genuinely addicted to (for example) both work and sex (unless the person's work was as an actor/actress in the pornographic film industry).The paper by Kraus et al. also makes a number of references to 'excessive/problematic sexual behavior' and appears to make the assumption that 'excessive' behaviour is bad (i.e. problematic). While CSB is typically excessive, excessive sex in itself is not necessarily problematic. Preoccupation with any behaviour in relation to addiction obviously needs to take into account the behavioural context, as this is more important in defining addictive behaviour than the amount of activity undertaken. As I have argued, the fundamental difference between healthy excessive enthusiasms and addictions is that healthy excessive enthusiasms add to life, whereas addictions take away from them [6]. The paper also appears to have an underlying assumption that empirical research from a neurobiological/genetic perspective should be treated more seriously than fro...