Impulse-control disorder

Did You Know?

• Dysfunction of the striatum may link obsessive–compulsive disorder, impulse-control disorders, and substance use disorder.
• Impulsiveness in later stages of OCD is caused by progressive dysfunction of the ventral striatal circuit.
• OCD is generally driven by desire to avoid harm, while ICD is driven by reward-seeking behavior.

DSM-5 Types

The DSM-5 groups several conditions under Disruptive, Impulse-Control, and Conduct Disorders, but does not assign each one to a specific subcategory. Trichotillomania and skin-picking now appear in the obsessive-compulsive chapter, while pathological gambling was renamed gambling disorder and moved to the addictive disorders section. Many other DSM-5 diagnoses can involve poor self-control, but those in this chapter typically involve behaviors that infringe on others’ rights or clash with social norms, authorities, or laws. Before the DSM-5 was published, proposals for new classifications included compulsive-impulsive internet use, sexual behaviors, skin picking, and shopping, but none were adopted. The DSM-5 notes that there is not enough evidence to establish diagnostic criteria for sex addiction, exercise addiction, or shopping addiction as mental disorders. Intermittent explosive disorder involves recurrent aggressive outbursts that are disproportionate to any trigger. One 2004 study of 253 people found a lifetime prevalence of 11.1% and a one-month prevalence of 3.2%, leading researchers to estimate 1.4 million people in the US have the disorder and 10 million have had it in their lifetime. This condition is dual-coded in the chapter because it relates to externalizing impulse-control problems. Pyromania involves repeated, impulsive urges to set fires. Studies of children and adolescents in the US report prevalence between 2.4% and 3.5%, with fire-setting more common among boys than girls.

ICD-11 types

The ICD-11 includes pyromania, kleptomania, and intermittent explosive disorder as impulse control disorders, while oppositional defiant disorder and conduct-dissocial disorder are listed under disruptive behaviour or dissocial disorders. It also includes compulsive sexual behavior disorder, substance-induced impulse control disorders, gambling disorder, gaming disorder, body-focused repetitive behavior disorders, and compulsive buying–shopping disorder. Sexual compulsion involves increased urge in sexual behavior and thoughts, leading to risky partner selection, increased STI risk, depression, and unwanted pregnancy; prevalence estimates from early 1990s US research are 5–6%, with male cases higher. Compulsive shopping involves frequent irresistible urges to shop even when purchases are unneeded or unaffordable; US prevalence is 2–8% of adults, with 80–95% of cases female, onset in late teens or early twenties, and generally chronic course.

Signs and symptoms

Signs and symptoms of impulse-control disorders vary by age, type of impulse control, environment, and sex. Complications of late Parkinson's disease may include eating, buying, compulsive gambling, sexual behavior, and related behaviors such as punding, hobbyism, and walkabout; prevalence studies indicate 13.6–36.0% of Parkinson's patients exhibit at least one ICD. There is significant co-occurrence of pathological gambling and personality disorder, partly due to common genetic vulnerability. Heritability of ICD is similar to other psychiatric disorders including substance use disorder, and genetic factors contribute to ICD development. Risk for subclinical pathological gambling is accounted for by alcohol dependence risk by 12–20% genetic and 3–8% environmental factors. High comorbidity exists between ADHD and other impulse-control disorders.

Treatment

Two treatment options exist for impulse-control disorders: psychosocial and pharmacological, with methodology informed by comorbid conditions. For pathological gambling, clomipramine and fluvoxamine have shown effectiveness, reducing problems by up to 90%. In trichotillomania, clomipramine is effective, but fluoxetine has not produced consistent positive results. Fluoxetine has shown positive results for pathological skin picking, though more research is needed, and in a 14-week double-blind study of 100 subjects with IED, it significantly reduced impulsive aggression and irritability; however, only 44% of fluoxetine responders and 29% of all fluoxetine subjects achieved full remission. Paroxetine has shown somewhat effective but inconsistent results, and escitalopram improved pathological gambling with anxiety symptoms. SSRIs show positive but inconsistent results, suggesting neurological heterogeneity in the impulse-control disorder spectrum. Cognitive behavioral therapy (CBT) has positive results for pathological gambling and sexual addiction, and is generally considered effective. Pyromania is harder to control in adults due to lack of cooperation, but CBT is effective in treating child pyromaniacs. For intermittent explosive disorder, Cognitive Relaxation and Coping Skills Therapy (CRCST) involves 12 sessions starting with relaxation training, then cognitive restructuring, exposure therapy, and focus on resisting aggressive impulses and taking preventative measures.