violence can be defined as overt behavior that involves the intent to inflict noxious stimulation or to behave destructively toward another organism . violent behavior in human society is a complex output of biological , behavioral , and social factors . epilepsy and violent behavior have long been regarded as similar because of their episodic or impulsive natures . violent behavior among patients with epilepsy can be categorized into peri - ictal violence ( preictal , ictal , and postictal ) , which occurs around the time of a seizure attack , and interictal violence , which has less of a temporal relationship with a seizure attack . there has been a belief that people with epilepsy are more prone to committing violent acts than the general population ; however , there has been no convincing evidence to indicate that epilepsy is associated with violent behavior . the prevalence of violence among patients with epilepsy can vary according to the definition of violent behavior , epilepsy subtypes , and the origin of the study population . for example , temporal lobe epilepsy had been reported to be related to a high rate of about 7% of violent acts . some studies have indicated that epileptic prisoners do not commit more violent crimes than nonepileptic prisoners . another report stated that the rate of epilepsy in prison populations was similar to those found in most economically disadvantaged communities , suggesting that socioeconomic conditions are an important factor leading patients with epilepsy to commit criminal behavior . combined medical diseases , such as alcohol dependence , brain injury , and psychosis , and frustrated social achievement may contribute to violent behavior . it is conceivable that only a minority of patients with epilepsy commit a violent crime . if we can elucidate potential violence - aggravating factors among patients with epilepsy , we may be able to understand the pathomechanism of aggression and possibly prevent further violent behavior . in this study , we set out to evaluate the clinical and criminal characteristics of epileptic patients who committed violent crimes . the national forensic hospital in gongju is a hospital - based correctional institution that was founded in 1987 by the ministry of justice of the republic of korea . it is a unique forensic hospital in the republic of korea , and those criminals who have committed crimes as a manifestation of their psychiatric or neurological diseases are incarcerated in the institution . when patients are admitted to the hospital , we perform routine blood tests , electroencephalography ( eeg ) , and the korean version of the wechsler adult intelligence scale , which measures the intelligent quotient ( iq ) . brain magnetic resonance imaging ( mri ) is considered when outside data is not available . between october 2007 and september 2008 , patients with epilepsy who were incarcerated in the forensic hospital due to violent crime were enrolled in the study . epilepsy was diagnosed when a patient had two or more unprovoked seizure attacks or when antiepileptic drugs had been prescribed for a diagnosis of epilepsy . all of the patients had been diagnosed with epilepsy before their crimes , and one neurologist confirmed the diagnosis after admission to the forensic hospital . the violent crimes included homicide , attempted murder , rape , assault , arson , and robbery . the seizure - control state was determined as good if a patient was in a state of remission for longer than a year . the study was reviewed and approved by the institutional review board of the national forensic hospital in gongju . a spearman test was performed to test for any correlation between the age of the patient at their first crime and values including epilepsy onset age , iq , and educational achievement with spss for windows ( version 12.0 ; spss , inc . , chicago , il , usa ) . the national forensic hospital in gongju is a hospital - based correctional institution that was founded in 1987 by the ministry of justice of the republic of korea . it is a unique forensic hospital in the republic of korea , and those criminals who have committed crimes as a manifestation of their psychiatric or neurological diseases are incarcerated in the institution . when patients are admitted to the hospital , we perform routine blood tests , electroencephalography ( eeg ) , and the korean version of the wechsler adult intelligence scale , which measures the intelligent quotient ( iq ) . brain magnetic resonance imaging ( mri ) is considered when outside data is not available . between october 2007 and september 2008 , patients with epilepsy who were incarcerated in the forensic hospital due to violent crime were enrolled in the study . epilepsy was diagnosed when a patient had two or more unprovoked seizure attacks or when antiepileptic drugs had been prescribed for a diagnosis of epilepsy . all of the patients had been diagnosed with epilepsy before their crimes , and one neurologist confirmed the diagnosis after admission to the forensic hospital . the violent crimes included homicide , attempted murder , rape , assault , arson , and robbery . the seizure - control state was determined as good if a patient was in a state of remission for longer than a year . the study was reviewed and approved by the institutional review board of the national forensic hospital in gongju . a spearman test was performed to test for any correlation between the age of the patient at their first crime and values including epilepsy onset age , iq , and educational achievement with spss for windows ( version 12.0 ; spss , inc . , chicago , il , usa ) . there were 17 epilepsy patients who had committed a violent crime , and these patients constituted 2.2% of the total patient population ( 761 ) in the forensic hospital . the mean age of the patients at epilepsy onset and at the time of their first crime was 15.5  14.5 years and 33.9  12.3 years , respectively . all of the patients were diagnosed with localization - related epilepsy , which involved either frontal lobe epilepsy or temporal lobe epilepsy ( table 1 ) . possible etiologies included head trauma in three patients , cerebral infection in two patients , and stroke in another . brain mri data , which was available for seven patients , revealed various structural lesions , including cerebral infarction , polymicrogyria , meningioma , surgical excision , and encephalomalatic change after head injury . fifteen out of the 17 patients were not taking regular antiepileptic medication prior to their crimes , partly because of economic problems or adverse effects of the drugs , but mostly because they did not recognize the importance of drug maintenance . ten patients were in a remission state with monotherapy , and five were being administered two antiepileptic medications . other combined medical conditions included mental retardation in seven patients , alcohol abuse in four , schizophrenia in three , and dementia in one . the types of crimes among the patients included murder in six patients , attempted murder in three , rape in three , assault in two , robbery in two , and arson in one . most of the patients did not experience overt seizure attacks before and after the crime , and they did not lose their consciousness or memory during the crime . however , two patients stated that they did not remember their criminal behavior , suggesting the possibility of postictal confusion . although the two patients experienced overt seizure attacks after admission , they had not shown any alteration of consciousness with violent behavior . ten patients ( 58.8% ) had previous criminal records , which were due to similar types of crimes as those discussed in this paper . seven patients were in a heavily drunken state when they committed their crimes ( table 1 ) . eight patients experienced psychosis , and two patients committed their crimes in response to auditory or visual hallucinations . in eight patients , a positive correlation existed between the age of onset of their first crimes and the patients iq scores , as illustrated in table 2 and figure 1 ( r = 0.533 , p = 0.033 ) . educational achievement was defined as the number of years that were spent in a school ( table 1 ) . seven out of 17 patients had finished middle school ( i.e. , they spent nine years in the school system ) , which is the final step of compulsory education in korea . occupational experience was mostly confined to temporary and daily work in seven patients , while two patients had regular occupations . four patients were divorced , and one patient was widowed because she had murdered her husband . regular contact by family members of at least one visit per year was maintained in five patients . all of the patients were diagnosed with localization - related epilepsy , which involved either frontal lobe epilepsy or temporal lobe epilepsy ( table 1 ) . possible etiologies included head trauma in three patients , cerebral infection in two patients , and stroke in another . brain mri data , which was available for seven patients , revealed various structural lesions , including cerebral infarction , polymicrogyria , meningioma , surgical excision , and encephalomalatic change after head injury . fifteen out of the 17 patients were not taking regular antiepileptic medication prior to their crimes , partly because of economic problems or adverse effects of the drugs , but mostly because they did not recognize the importance of drug maintenance . ten patients were in a remission state with monotherapy , and five were being administered two antiepileptic medications . other combined medical conditions included mental retardation in seven patients , alcohol abuse in four , schizophrenia in three , and dementia in one . the types of crimes among the patients included murder in six patients , attempted murder in three , rape in three , assault in two , robbery in two , and arson in one . most of the patients did not experience overt seizure attacks before and after the crime , and they did not lose their consciousness or memory during the crime . however , two patients stated that they did not remember their criminal behavior , suggesting the possibility of postictal confusion . although the two patients experienced overt seizure attacks after admission , they had not shown any alteration of consciousness with violent behavior . ten patients ( 58.8% ) had previous criminal records , which were due to similar types of crimes as those discussed in this paper . seven patients were in a heavily drunken state when they committed their crimes ( table 1 ) . eight patients experienced psychosis , and two patients committed their crimes in response to auditory or visual hallucinations . in eight patients , a positive correlation existed between the age of onset of their first crimes and the patients iq scores , as illustrated in table 2 and figure 1 ( r = 0.533 , p = 0.033 ) . educational achievement was defined as the number of years that were spent in a school ( table 1 ) . seven out of 17 patients had finished middle school ( i.e. , they spent nine years in the school system ) , which is the final step of compulsory education in korea . occupational experience was mostly confined to temporary and daily work in seven patients , while two patients had regular occupations . four patients were divorced , and one patient was widowed because she had murdered her husband . regular contact by family members of at least one visit per year was maintained in five patients . in this national center - based retrospective study , the most common epilepsy subtype in patients with violent crimes was localization - related epilepsy , and these patients showed favorable responses to medical treatment . it was noted that violent crimes were rarely observed during ictal or postictal periods , suggesting that neuropsychological and social factors might interplay and lead to violence rather than the violence being caused by just the epileptic seizure itself . our study suggested that a low level of intelligence was related to an earlier onset of crimes . educational achievement was markedly limited among the epileptic criminals , as were occupational experience and family support . the temporal relationship between seizure attacks and violent crimes was very subtle in most cases , suggesting that interictal violent behavior was more commonly associated with crimes than that of ictal or postictal periods . although there have been several reports about peri - ictal violence , those seemed to be associated with purposeless movement or resistive activity against restriction . there was a recent report illustrating violent crimes that were probably due to epileptic automatism . however , it is very challenging to prove violent behaviors as an ictal manifestation , given that video - eeg monitoring is required to determine whether there were ictal discharges during the behavior . two of our patients reported decreased levels of consciousness and amnesia after committing rape , but seizure attacks can not be guaranteed at that time because such a complex behavior would be difficult to perform during a seizure attack . in addition , a high level of emotional excitability could also result in transient memory dysfunction . it is generally accepted that violent behavior among epilepsy patients is most commonly observed in the interictal period . low intelligence has been regarded as one of the major risk factors of violence among epilepsy patients . our results revealed a positive correlation between the age at the first crime and iq score , suggesting that epilepsy patients with low intelligence might be prone to violent behavior at a younger age . although it is hard to ascertain that low intelligence is a direct cause of violent crime among epilepsy patients , low intelligence may force them to remain in a low socioeconomic state , which may possibly increase criminal behaviors . another possible explanation is that structural brain abnormalities may result in epilepsy , intellectual disability , and impulse control dysfunction , and each of these can contribute to an overall disability . however , it is also possible that early criminal behavior might have caused social discrimination , including a lack of educational opportunities , which would have resulted in a low iq measured upon admission . two of our patients committed a violent crime in response to a psychotic manifestation in the form of auditory hallucinations and persecutory delusions . those crimes might have been prevented if the patients had been adequately treated with antipsychotics . considering that seven out of 17 patients were drunk before the crime , inebriation seems to be another violence - provoking factor among epileptic patients , justifying educational programs for the responsible use of alcohol and/or abstinence programs . although korea has had a mandatory educational system since 1954 , and given that the majority of the population has completed middle school after 1993 , our study revealed that ten patients ( 58.8% ) could not graduate from middle school . the undereducated proportion of patients in our study was much larger compared to the percentage of general criminals who did not finish middle school ( 6.5% ) . the level of educational achievement among epileptic criminals seemed to be stationary compared to a previous study from the same institution , which revealed that 45.5% ( 10 out of 22 patients ) of patients had not graduated from middle school . poor employment conditions among epilepsy criminals was shown in another study , which reported a 92.3% ( 12 out of 13 patients ) unemployment rate . family support and marital relationships were lacking in the majority of the patients , which was reflected by a high divorce rate and lack of family contact during incarceration . disrupted educational achievement , occupational opportunities , and family background may prohibit social integration after discharge and trigger future crime . although this is a single national center - based study , our study population likely included the entire population of violent criminals with epilepsy specific to the selected time period because there is only one forensic hospital in south korea . we chose those patients with violent crime in order to homogenize the study population ; however , selection bias may have taken place since the court ultimately decides the referral of epileptic criminals to the forensic hospital , even though medical advice also plays a substantial role . in addition , a small percentage of the study population may have produced biased results . further studies comparing epilepsy patients with and without violent behavior may increase our understanding of the relationship between epilepsy and aggression . low intelligence , alcohol abuse , and psychosis appear to be associated with criminal activity among epilepsy patients . medical interventions to treat psychosis and alcohol abuse and social reinforcement may be helpful to prevent future violent behavior .
background and purpose : we investigated the clinical and criminal characteristics of patients with epilepsy who had committed violent crimes in order to understand the mechanism of violence and to prevent future criminal activity.methods:we reviewed medical and legal reports of criminals with epilepsy who were incarcerated in the korean national forensic hospital between october 2007 and september 2008.results:of 761 criminals admitted to the national forensic hospital , 17 patients ( 2.2% ) were diagnosed with epilepsy . 
 all of them had localization - related epilepsy , and no patient reported an overt seizure attack around the time of a crime . 
 psychosis was present in eight patients , and seven patients were in a drunken state at the time of the crimes . 
 there was a positive correlation between the patients age at their first crime and their intelligence quotient score.conclusions:these results suggest that most violent crimes take place during interictal periods , and diverse medical conditions , including inebriation , psychosis , and low intelligence , are associated with violent crimes among epileptic patients .