Excessive levels of non-paraphilic sexual behaviour are characterized by the extreme and repetitive expression of culturally adopted sexual behaviours  Many terms have been used to describe excessive sexual behaviour, such as compulsive sexual behaviour (CSB), hypersexuality, and sexual addiction . Sexual addiction is considered to be a behavioural addiction, however the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) does not recognize sexual addiction as a disorder . There is controversy as to whether it should be classified as an impulsive control disorder, an obsessive-compulsive disorder, or if it even exists . However, behavioural addictions have recently been shown to share the same core features as substance addiction . This includes a loss of control of sexual urges, behaviours, and thoughts, as well as tolerance, withdrawal, and continuing despite adverse consequences . Sexual addiction is thought to take many forms, such as compulsive masturbation, extensive pornography use, and multiple affairs . Also, sexual behaviour and substance use activate the same brain pathway (the mesolimbic dopamine pathway) which is the reward circuit involved in reinforcing survival behaviours . Functional neuroimaging of patients with brain trauma has shown that lesions in the prefrontal cortex and temporal lobes are associated with hypersexuality and loss of inhibition . Also, frontal lobe damage has been thought to lead to CSB . Pharmacological treatments for sexual addiction such as selective serotonin reuptake inhibitors (SSRIs) and antiandrogens have been shown to decrease the frequency and intensity of sexual urges, and allow for greater control over obsessive thoughts and behaviours . Psychotherapy and self-help groups are also effective in treating sexual addiction .
Table of Contents
1. Characterization of Excessive Sexual Behaviour
1.1 Sexual Addiction
|Video source:https://www.youtube.com/watch?v=y1ltOd7laNU (2008).|
Sexual addiction is considered a behavioural addiction, which involves a compulsion to engage in a behaviour repeatedly despite adverse physical, mental, social, and financial consequences . Some researchers believe we can get addicted to sex the same way we get addicted to drugs and use it to manage internal distress, similar to compulsive gamblers, over eaters, or drug users . Orford first described the addictive component of excessive nonparaphilic sexual behaviour, and highlighted the features that fit within the diagnostic criteria for an addictive disorder . However, the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) does not recognize sexual addiction as a disorder due to a lack of empirical research and consensus validating sexual behaviour as an addiction . No epidemiological studies have been conducted to assess sexual addiction using standardized diagnostic criteria . Commonalities between sexual addiction and substance addiction include an increase in sexual activity as the disorder develops, difficulty in reducing the frequency of sexual activity, withdrawal symptoms, and maintenance despite adverse consequences (such as contracting sexually transmitted diseases, marital issues, and economic problems) . Potenza and others showed that among subjects with supposed sexual addiction, 98% reported withdrawal symptoms, 94% were unable to control or reduce sexual behaviour, 92% spent increasing amounts of time on sexual activity, and 85% pursued sexual behaviour despite adverse physical or psychological consequences . Also, in men and women who met criteria for CSB, comorbidities between excessive nonparaphilic sexual behaviour and other addictions was 71% in one sample, and 64% in another sample . The prevalence of sexual addiction is approximately 3 to 6% of the population , with higher rates proposed for men, sexual offenders, and patients with HIV . Goodman proposed criteria to describe “sexual addiction” as a disorder by putting “sexual behaviour” in place of the word “substance” in the DSM IV criteria for substance addiction . Also, Kafka described excessive nonparaphilic sexual behaviour by the term “Hypersexual Disorder”, and has proposed criteria for the Fifth Edition of DSM (DSM-V) . However, there are a lack of studies and scientific data to validate these criteria . There is a need for future research to improve the characterization of excessive nonparaphilic sexual behaviour, because it’s classification as an addictive disorder is still up for debate.
1.2 Impulse-Control Disorder Hypothesis
Behavioural addictions are sometimes referred to as impulse-control disorders . Impulse control disorders are characterized by pursuing behaviours harmful to ones self or others while failing to resist the impulse, drive, or temptation to act on them . This model proposes that patients with excessive nonparaphilic sexual behavior may fail to resist a sexual activity impulse or temptation . Feelings of tension or arousal might provoke the behaviour, which elicits gratification and transient relief from negative emotional states, however feelings of distress and guilt often ensue . In a study where 31% of inpatients had a lifetime diagnosis of impulsivity disorder, 4.9% of them had excessive nonparaphilic sexual behaviour .
1.3 Obsessive-Compulsive Hypothesis
Excessive nonparaphilic sexual behaviour has been termed “compulsive sexual behaviour” (CSB) due to similarities with obsessive-compulsive disorder (OCD) . Excessive nonparaphilic sexual behaviour is characterized by intrusive repetitive thoughts, which are typical of obsessional thoughts described in OCD . Sexual “compulsions” are initially resisted, and are enacted to reduce anxiety, followed by feelings of distress. Black and others found that in males and females suffering from CSB for a mean of nine years, 42% reported intrusive and repetitive sexual fantasies, and 67% reported repetitive sexual behavior initially resisted and followed by negative self-esteem . Other authors have highlighted the similar responses of obsessive-compulsive behavior and excessive nonparaphilic sexual behavior to treatments using SSRIs and cognitive behavioral therapy . There are inconsistencies with this model because OCD is not associated with pleasure (except for tension relief), however pleasure might elicit repetitive thoughts and excessive levels of sexual behaviour . Also, the comorbidity rates between these two disorders are low .
2. Neuroanatomical Structures and Neurotransmitters
2.1 Mesolimbic Dopamine Pathway
|The Reward Pathway. Image source: Taber et al., 2012 |
The brain’s reward system is critical in ensuring behaviours for survival and reproduction, such as eating and sexual activity . This reward pathway is called the mesolimbic dopamine pathway. The ventral tegmental area (VTA) in the midbrain is connected to the nucleus accumbens (NAcc) in the ventral striatum by the medial forebrain bundle (MFB) . The neurons of the MFB contain the neurotransmitters dopamine, serotonin, and noradrenaline. Natural rewards (food and sex) and artificial rewards (drugs of abuse) all activate the dopaminergic pathway causing an increase in dopamine in the NAcc, leading to positive reinforcing effects . Functional neuroimaging studies in humans have shown that rewards increase dopamine release in the ventral striatum  and the ventral striatum is associated with the sensation of pleasure when stimulated . Additionally, positron emission tomography scans of healthy participants during orgasm and ejaculation displayed strong VTA activation, which is the same area activated with the pleasurable sensations of heroin use . Chronic drug administration causes reward thresholds to increase, indicating a compromised dopamine system. Decreased dopamine function might cause withdrawal and negative emotional states, and continued substance use in needed to restore normal dopamine levels .
2.2 Frontal Lobes
Impulse control disorders are typically associated with frontal lobe white matter disorganization and impaired executive function and inhibitory control . Miner and others (2009) conducted the first brain imaging study to investigate the impulsive aspects of CSB through behavioural tests and examination of white matter in the frontal lobes. In this study, although patients with CSB were found to be more impulsive than controls, the diffusion tensor imaging (DTI) results were inconsistent with results from impulse control disorders. The results of this study are important because although CSB is characterized by impulsivity, other brain areas are likely involved in the regulation of excessive sexual behaviours .
2.3 Prefrontal Cortex and Temporal Lobes
In patients with brain trauma, damage to the prefrontal cortex was associated with disinhibition and hypersexuality . Also, bilateral temporal lobe lesions due to head trauma or herpes simplex encephalitis produced the Klüver-Bucy syndrome of hypersexuality . According to brain-injury rehabilitation programs for outpatients, patients with hypersexuality made inappropriate sexual comments towards others, engaged in sexual exhibitionism, and engaged in sexually deviant criminal activities in extreme conditions . However, hypersexuality is much more rare than hyposexuality in patients with brain trauma .
3.1 Pharmacological Treatments
Patients with sexual addiction suffer embarrassment, and so they do not often seek medical advice . However, behavioral addictions are increasingly being recognized as treatable forms of addictions . The two main pharmacological treatments for sexual addiction include SSRIs and antiandrogens.
3.11 Selective Serotonin Reuptake Inhibitors (SSRIs)
Impulsive behaviours are associated with low serotonin levels, and so SSRIs (which act to increase serotonin levels in the brain) have been used to treat CSB . In one double blind study using the SSRI citalopram, a dose of 20-60 mg was compared to a placebo for 12 weeks in men with CSB . Citalopram treatment resulted in a significant decrease in sexual desire, frequency of masturbation, and pornography use . Similarly, treatment with the SSRI fluoxetine (20-40 mg) reduced inappropriate sexual behaviour in subjects with excessive sexual behaviour .
The antiandrogen medications used to treat excessive nonparaphilic sexual behaviour are cyproterone acetate (CPA) and medroxyprogesterone acetate (MPA) . CPA binds to all androgen receptors to competitively inhibit testosterone, and further inhibit gonadotropin-releasing hormone and luteinizing hormone release. CPA is registered in more than 20 countries, and a low dose is able to control deviant sexual fantasies, compulsions, and behaviours. Additionally, MPA effectively reduces the sexual drive of healthy males .
3.2 Cognitive Behavioural Therapy
If pharmacological treatments are used to treat sexual addiction, they should be used in collaboration with psychotherapy and behavioural therapy . Cognitive behavioural therapy is the most endorsed psychological treatment for excessive sexual behaviour . This approach helps to limit excessive sexual activity by encouraging abstinence from sexual behaviour in the first phase of treatment. Additionally, this treatment has been shown to help increase self-esteem and decrease levels of depression and anxiety . Self-help groups such as “Sexual Addicts Anonymous” and programs modeling the 12-Step program of Alcoholics Anonymous are also available to help cope with sexual addiction .