The basic mechanism that leads to the majority of violent activities is a loss of control over the impulses. Of course, serious brain damage  increases impulsivity, but in most circumstances, for example, intoxication, sensation-seeking provocation, delinquent peers, disintegration of family structure, dissolution of cultural institutions, desperation and so on can lead to even those with a healthy brain to lose control.

Not all mental disorders contribute to violence. Studies all over the world show that only certain mental and behavioural disorders are commonly associated with criminal activities. Drug dependence, for example, and its association with crime is an undisputed issue. Drug intoxication acts like catalyst in the execution of the act in healthy as well as sick brains alike. It is worth noting that around 70 percent of mentally ill offenders also abuse drugs before committing a crime.

People with schizophrenia—registering abnormal sensations through the sense organs (hallucinations) and harbouring odd beliefs, persecutory delusions for instance, and acting on those delusions—are definitely on the top of the list of mentally ill offenders. Many times, epilepsy, and its complications, in which one’s brain has abnormal electrical discharges and which can lead to one’s acting as an automaton, is also notoriously associated with violent crimes. People with dementia—where a degeneration of the brain results in the loss of higher cognitive functions and social inhibition—have been traditionally linked with committing sex offences against children and with shoplifting. Huntington’s disease, where the victim can exhibit inappropriate sexual activities, as well as antisocial, cruel, callous and violent behaviour, has been a matter of great interest in forensic psychiatry. Mental retardation, due to low intelligence, is also linked to crimes, with the perpetrators not being able to understand the illegal nature of the acts. People with the manic phase of bipolar mood disorder— owing to the individual’s overestimation of their ability, disinhibition and increased impulsivity—are also liable to commit crimes.

Antisocial personalities, also known as sociopaths, are traditionally depicted as serial killers, and they are described as being devoid of compassion and deriving pleasure from breaking the rules and witnessing other beings suffer. And  crime literature is plagued by characters afflicted with multiple personality disorder, a rare condition, in which the same person assumes different altar personalities, and commits crimes while being another, the original personality being totally oblivious of the other’s action.

In most countries, there has been a long history of mental disorders (legal insanity) being used as a pretext for pleas in criminal cases, in what is known as the “Insanity Defence”. But not all mental illnesses are entitled to legal insanity status. One has to prove that she/he was of unsound mind at the time of committing the crime. Unsound mind means being incapable of knowing the nature of the act, or not knowing what he or she is doing wrong and how the behavior is contrary to law. This description is often very arbitrary and difficult to prove, as nobody would have assessed the offender at the crime scene. Total acquittals of offenders on the basis of an insanity defense alone are rare phenomena all over the world, but many such offenders are tagged with having diminished criminal responsibilities, and they serve terms and receive treatments in special mental health institutions.

In Nepal, we seldom hear about such trials. Our laws associated with this issue are very rudimentary or outdated, and needless to say, stakeholders have limited knowledge. Not many criminals are screened for mental disorders, and even when such screens are conducted, they are done very casually, without the use of standard protocols, often by untrained staff, ones who have not been trained in psychiatry. And to add to this carelessness, the findings are usually interpreted by law personnel. Many mentally ill offenders are thus sentenced as any other guilty party, and they are locked up in common prisons, and lack the care and facilities that an otherwise ill person would require. Ironically, sometimes, jail is the only safe place for them because the ‘sane’ society can immediately victimise them out in the open.

Although mentally ill offenders amount to only a minority as far as crimes are concerned, there should thus be mandatory screenings for all, before court trials, in order to ensure proper justice. After all, it would be unfair to deal with mentally ill offenders in the same way as healthy ones. Let us hope things will improve with the new constitution and hope that there will be more scientifically backed amendments to our legislations.

Shakya is an Assoc Professor of Psychiatry, Patan  academy of Health Sciences, Lalitpur