1. Types

Disorders characterized by impulsivity that were not categorized elsewhere in the DSM-IV-TR were also included in the category "Impulse-control disorders not elsewhere classified". Trichotillomania (hair-pulling) and skin-picking were moved in DSM-5 to the obsessive-compulsive chapter.^[1] Additionally, other disorders not specifically listed in this category are often classed as impulsivity disorders. Terminology was changed in the DSM-V from "Not Otherwise Classified" to "Not Elsewhere Classified".^[2]

1.1. Sexual Compulsion

Sexual compulsion includes an increased urge in sexual behavior and thoughts. This compulsion may also lead to several consequences in the individual's life, including risky partner selection, increased chance for STDs and depression, as well as unwanted pregnancy. There has not yet been a determined estimate of its prevalence due to the secretiveness of the disorder. However, research conducted in the early 1990s in the United States gave prevalence estimates between 5–6% in the U.S. population, with male cases being higher than female.^[3]

1.2. Internet Addiction

The disorder of Internet addiction has only recently been taken into consideration and has been added as a form of ICD. It is characterized by excessive and damaging usage of Internet with increased amount of time spent chatting, web surfing, gambling, shopping or consuming pornography. Excessive and problematic Internet use has been reported across all age, social, economic, and educational ranges. Although initially thought to occur mostly in males, increasing rates have been also observed in females. However, no epidemiological study has been conducted yet to understand its prevalence.^[3]

1.3. Compulsive Shopping

Compulsive shopping or buying is characterized by a frequent irresistible urge to shop even if the purchases are not needed or cannot be afforded. The prevalence of compulsive buying in the U.S. has been estimated to be 2–8% of the general adult population, with 80–95% of these cases being females. The onset is believed to occur in late teens or early twenties and the disorder is considered to be generally chronic.^[3][4]

1.4. Pyromania

Pyromania is characterized by impulsive and repetitive urges to deliberately start fires. Because of its nature, the number of studies performed for fire-setting are understandably very few. However, studies done on children and adolescents suffering from pyromania have reported its prevalence to be between 2.4–3.5% in the United States. It has also been observed that the incidence of fire-setting is more common in juvenile and teenage boys than girls of the same age.^[3]

1.5. Intermittent Explosive Disorder

Intermittent explosive disorder or IED is a clinical condition of experiencing recurrent aggressive episodes that are out of proportion of any given stressor. Earlier studies reported a prevalence rate between 1–2% in a clinical setting, however a study done by Coccaro and colleagues in 2004 had reported about 11.1% lifetime prevalence and 3.2% one month prevalence in a sample of a moderate number of individuals (n=253). Based on the study, Coccaro and colleagues estimated the prevalence of IED in 1.4 million individuals in the US and 10 million with lifetime IED.^[3]

1.6. Kleptomania

Kleptomania is characterized by an impulsive urge to steal purely for the sake of gratification. In the U.S. the presence of kleptomania is unknown but has been estimated at 6 per 1000 individuals. Kleptomania is also thought to be the cause of 5% of annual shoplifting in the U.S. If true, 100,000 arrests are made in the U.S. annually due to kleptomaniac behavior.^[3]

2. Signs and Symptoms

The signs and symptoms of impulse-control disorders vary based on the age of the persons suffering from them, the actual type of impulse-control that they are struggling with, the environment in which they are living, and whether they are male or female.^[5]

2.1. Co-Morbidity

Complications of late Parkinson's disease may include a range of impulse-control disorders, including eating, buying, compulsive gambling, sexual behavior, and related behaviors (punding, hobbyism and walkabout). Prevalence studies suggest that ICDs occur in 13.6–36.0% of Parkinson's patients exhibited at least one form of ICD.^[6][7][8][9] There is a significant co-occurrence of pathological gambling and personality disorder, and is suggested to be caused partly by their common "genetic vulnerability".^[10][11] The degree of heritability to ICD is similar to other psychiatric disorders including substance use disorder. There has also been found a genetic factor to the development of ICD just as there is for substance use disorder. The risk for subclinical PG in a population is accounted for by the risk of alcohol dependence by about 12–20% genetic and 3–8% environmental factors.^[10] There is a high rate of co-morbidity between ADHD and other impulse-control disorders.^[1]

3. Mechanism

Dysfunction of the striatum may prove to be the link between OCD, ICD and SUD. According to research, the 'impulsiveness' that occurs in the later stages of OCD is caused by progressive dysfunction of the ventral striatal circuit. Whereas in case of ICD and SUD, the increased dysfunction of dorsal striatal circuit increases the "ICD and SUD behaviours that are driven by the compulsive processes".^[12] OCD and ICD have traditionally been viewed as two very different disorders, the former one is generally driven by the desire to avoid harm whereas the latter one driven "by reward-seeking behaviour". Still, there are certain behaviors similar in both, for example the compulsive actions of ICD patients and the behavior of reward-seeking (for example hoarding) in OCD patients.^[12]

4. Treatment

Impulse-control disorders have two treatment options: psychosocial and pharmacological.^[13] Treatment methodology is informed by the presence of comorbid conditions.^[3]

4.1. Medication

In the case of pathological gambling, along with fluvoxamine, clomipramine has been shown effective in the treatment, with reducing the problems of pathological gambling in a subject by up to 90%. Whereas in trichotillomania, the use of clomipramine has again been found to be effective, fluoxetine has not produced consistent positive results. Fluoxetine, however, has produced positive results in the treatment of pathological skin picking disorder,^[3][14] although more research is needed to conclude this information. Fluoxetine has also been evaluated in treating IED and demonstrated significant improvement in reducing frequency and severity of impulsive aggression and irritability in a sample of 100 subjects who were randomized into a 14-week, double-blind study. Despite a large decrease in impulsive aggression behavior from baseline, only 44% of fluoxetine responders and 29% of all fluoxetine subjects were considered to be in full remission at the end of the study.^[15] Paroxetine has shown to be somewhat effective although the results are inconsistent. Another medication, escitalopram, has shown to improve the condition of the subjects of pathological gambling with anxiety symptoms. The results suggest that although SSRIs have shown positive results in the treatment of pathological gambling, inconsistent results with the use of SSRIs have been obtained which might suggest a neurological heterogeneity in the impulse-control disorder spectrum.^[14]

4.2. Psychosocial

The psychosocial approach to the treatment of ICDs includes cognitive behavioral therapy (CBT) which has been reported to have positive results in the case of treatment of pathological gambling and sexual addiction. There is general consensus that cognitive-behavioural therapies offer an effective intervention model.^[16]

Pathological gambling

Systematic desensitization, aversive therapy, covert sensitization, imaginal desensitization, and stimulus control have been proven to be successful in the treatments to the problems of pathological gambling. Also, "cognitive techniques such as psychoeducation, cognitive-restructuring, and relapse prevention" have proven to be effective in the treatments of such cases.

Pathological gambling

Systematic desensitization, aversive therapy, covert sensitization, imaginal desensitization, and stimulus control have been proven to be successful in the treatments to the problems of pathological gambling. Also, "cognitive techniques such as psychoeducation, cognitive-restructuring, and relapse prevention" have proven to be effective in the treatments of such cases.

^[16]

Pyromania

Pyromania is harder to control in adults due to lack of co-operation; however, CBT is effective in treating child pyromaniacs. (Frey 2001)

Intermittent explosive disorder

Along with several other methods of treatments, cognitive behavioural therapy has also shown to be effective in the case of Intermittent explosive disorder as well. Cognitive Relaxation and Coping Skills Therapy (CRCST), which consists of 12 sessions starting first with the relaxation training followed by cognitive restructuring, then exposure therapy is taken. Later, the focus is on resisting aggressive impulses and taking other preventative measures.

Kleptomania

In the case of kleptomania, the cognitive behaviour techniques used in these cases consists of covert sensitization, imaginal desensitization, systematic desensitization, aversion therapy, relaxation training, and "alternative sources of satisfaction".

^[16]

Compulsive buying

Although compulsive buying falls under the category of Impulse-control disorder – Not Otherwise Specified in the DSM-IV-TR, some researchers have suggested that it consists of core features that represent impulse-control disorders which includes preceding tension, difficult to resist urges and relief or pleasure after action. The efficiency of cognitive behavior therapy for compulsive buying is not truly determined yet; however, common techniques for the treatment include exposure and response prevention, relapse prevention, cognitive restructuring, covert sensitization, and stimulus control.

^[16]