Bipolar disorder has been linked to increased agitation and aggressive behavior in some individuals, but for these individuals, aggressiveness is limited to manic and/or depressive episodes, whereas individuals with IED experience aggressive behavior even during periods with a neutral or positive mood.In one clinical study, the two disorders co-occurred 60% of the time. Patients report manic-like symptoms occurring just before outbursts and continuing throughout. According to a study, the average onset age of IED was around five years earlier than the onset age of bipolar disorder, indicating a possible correlation between the two.Similarly, alcohol and other substance use disorders may exhibit increased aggressiveness, but unless this aggression is experienced outside of periods of acute intoxication and withdrawal, no diagnosis of IED is given. For chronic disorders, such as PTSD, it is important to assess whether the level of aggression met IED criteria before the development of another disorder. In antisocial personality disorder, interpersonal aggression is usually instrumental in nature (i.e., motivated by tangible rewards), whereas IED is more of an impulsive, unpremeditated reaction to situational stress. Treatment
Although there is no cure, treatment is attempted through cognitive behavioral therapy and psychotropic medication regimens, though the pharmaceutical options have shown limited success. Therapy aids in helping the patient recognize the impulses in hopes of achieving a level of awareness and control of the outbursts, along with treating the emotional stress that accompanies these episodes. Multiple drug regimens are frequently indicated for IED patients.
Among a clinical population, a 2005 study found the lifetime prevalence of IED to be 6.3%.Prevalence appears to be higher in men than in women.Of US subjects with IED, 67.8% had engaged in direct interpersonal aggression, 20.9% in threatened interpersonal aggression, and 11.4% in aggression against objects. Subjects reported engaging in 27.8 high-severity aggressive acts during their worst year, with 2–3 outbursts requiring medical attention. Across the lifespan, the mean value of property damage due to aggressive outbursts was $1603.A study in the March 2016 Journal of Clinical Psychiatry suggests a relationship between infection with the parasite Toxoplasma gondii and psychiatric aggression such as IED. History
In the first edition of the American Psychiatric Associations Diagnostic and Statistical Manual (DSM-I), a disorder of impulsive aggression was referred to as a passive-aggressive personality type (aggressive type). This construct was characterized by a "persistent reaction to frustration are "generally excitable, aggressive, and over-responsive to environmental pressures" with "gross outbursts of rage or of verbal or physical aggressiveness different from their usual behavior".In the third edition (DSM-III), this was for the first time codified as intermittent explosive disorder and assigned clinical disorder status under Axis I. However, some researchers saw the criteria as poorly operationalized. About 80% of individuals who would now be diagnosed with the disorder would have been excluded.In the DSM-IV, the criteria were improved but still lacked objective criteria for the intensity, frequency, and nature of aggressive acts to meet criteria for IED.