Strictly speaking, 'forensic' psychiatry could refer to any aspect of psychiatry with a legal dimension. In practice, however, the term forensic psychiatry applies mainly to the interface between psychiatry and offending (criminal) behaviour.

For convenience, risk assessment is also discussed here.

Forensic psychiatrists are psychiatrists (mostly general adult but some child and adolescent as well) with special knowledge of offending behaviour among the mentally disordered, and the law relating to this. Their role includes:

• Assessment and care of patients in prisons, Medium Secure Units and Special Hospitals
• Psychiatric reports on criminal matters for courts and lawyers.
• Court Diversion Schemes for mentally disordered offenders (MDOs).
• Supervision of patients in the community, for example those on restriction orders (s37/41) of the Mental Health Act
  
• Consultation service to general psychiatrists.
  

Considerable political and media interest in forensic psychiatry has followed a recent succession of well-publicised individual ìscandalsî; for example, crimes by MDOs leading to calls for them to be detained permanently in psychiatric hospitals. Measures such as the Supervision Register and Care Programme Approach have been introduced, in part, in response to such pressures, though in the case of the Supervision Register have soon after been abolished again.

OFFENDING BEHAVIOUR Community surveys show that offending behaviour is extremely common, and that the vast majority of the population have broken the law in some way at some time. Generally speaking, offending behaviour is commoner in males, and peaks during the teenage years, gradually becoming less frequent thereafter.

Most cases involve minor property offences such as theft and vandalism. Only a proportion is reported, and only a fraction of this results in any conviction. Of people convicted, the proportion going on to become persistent serious offenders is small.

Causes of offending behaviour are predominantly social and environmental, rather than psychiatric. Conduct disorder in children (ìjuvenile delinquencyî) often persists into adulthood as criminality and/or antisocial personality. Criminality tends to run in families. Twin and adoption studies indicate some specific genetic component to this inheritance, and up to half of antisocial behaviour may have a genetic basis.

However, other factors such as coming from a large impoverished family, poor parenting, a culture of criminal behaviour in the neighbourhood and school, and low intelligence are thought to be of greater influence.

Male offenders outnumber female ones about 10-fold, and male prisoners outnumber female ones about 30-fold. Both cultural and biological factors contribute to this discrepancy. Female prisoners have more mental and physical disease than male ones.

Mental Disorder in Offenders Because of the difficulty in obtaining representative samples of offenders in the community, surveys on mental disorder amongst offenders have mainly been done on those in prison. Prevalence of mental disorder amongst prisoners, whether remanded or sentenced, is much higher than in the community. Figures have obviously varied between different populations studied, but a fifth of women prisoners and a third or more of male prisoners have antisocial personality disorder; prisoners were 10 times likelier than the general population to have psychosis or personality disorder (1). 50% or more may have abused substances at some time.

Criminality and violence in psychiatric patients There is an excess of offending, including violence, amongst those with mental disorder. However, antisocial personality disorder and substance misuse are stronger risk factors than mental illnesses such as schizophrenia. The bulk of offending in general, and violence in particular, has nothing to do with mental illness. A recent study, for example, (2) found that about 5% of violent crimes were committed by those with psychosis (which has a prevalence of about 1%); the association was stronger in females.

PREDICTING VIOLENCE AND DANGEROUSNESS Dangerousness varies according to the situation, and is impossible to predict with complete accuracy in individual cases. Nevertheless, general guidance can be given. Risk factors for repeated violence include:

• Past history of violence: this is by far the most important guide to present and future risk.
• Personal/family history of criminality/substance misuse/suicidal behaviour.
• Preoccupation with, or threats of, violence.
• Psychiatric disorder, especially with paranoid delusions or command hallucinations regarding violence
• Cold/callous explosive/antisocial personality traits.
• Impulsivity/irritability/emotional arousal.
• Ready availability of a weapon and a victim.
  

In a potentially violent situation in psychiatric practice, consider the above factors with due regard for intuition and common sense. If the interviewer feels anxiety or fear, it is prudent to adjourn the interview to seek assistance and advice.

Managing Risk ìRisk assessmentî is an important part of the work of mental health professionals. In forensic psychiatry, risk to others will be a concern as well as risk to self.

It is the responsibility of each practitioner and of the system he works in to assess risk continuously, and to try to manage it so as to reduce is as far as possible.

Risk assessment should be integrated into all aspects of modern psychiatry. The use of printed or computerized forms can help to ensure that assessments are done, recorded and, most importantly, communicated to others. Following adverse events, it has been frequently found that some team members were not in possession of key risk information when taking important decisions.

Risk assessment is especially important when something is changing in the patientís care, for example, reduction of frequency of observation on a ward or discharge from hospital.

When things do go wrong, there should be non-judgmental efforts to find out why, so that improvements can be made.

PSYCHIATRIC ASPECTS OF SPECIFIC OFFENCES

Homicide ìUnlawful homicideî includes murder, manslaughter and infanticide. The legal definition of murder requires that the crime was premeditated and the accused was fully responsible for the act. If these conditions are not fulfilled, the offence becomes manslaughter.

There are 800ñ900 homicides per year in England and Wales. In about 75% of cases, killer and victim are well known to each other. Alcohol and other substances are often a factor, both in the background and at the time of the offence. Up to 15% commit suicide soon after their crime.

A recent review (3) indicates that there are about 40 homicides per year done by people in contact with mental health services in the 12 months prior to the event. (To put this in context, this is roughly the same number as those done by (non-psychiatric) offenders on probation.).

However, surveys indicate that up to 50% of killers can be diagnosed with a mental disorder of some kind: mainly personality disorder and substance misuse, though depressive disorder and psychosis also occur.

The legal finding of diminished responsibility (see below), applies in less than 5% of homicides. The law classifies diminished responsibility, infanticide, homicide in a failed pact of suicide and not guilty by reason of insanity (see below), as ìabnormal homicidesî. Less than 1 in 6 homicides are classified as ìabnormalî.

The presence of a mental disorder may permit a murder charge to be reduced to manslaughter on the grounds of diminished responsibility. A verdict of murder always carries a sentence of life imprisonment, but manslaughter may receive any sentence, including a hospital order under the Mental Health Act 1983, or even a non-custodial sentence.

A rare plea, in practice reserved for murder cases, is ìnot guilty by reason of insanityî when the offender fulfils the MacNaughten Rules, that is he either did not know the nature and quality of his act, or did not know that it was wrong. A deluded patient is assumed to be under the same degree of responsibility as if the delusions were true. If this plea is successful, the accused is sent to a psychiatric hospital under the equivalent of a section 37 of the Mental Health Act.

About half of those accused of murder claim amnesia for the event, but this is not an adequate defence, nor is voluntary intoxication with alcohol or drugs. Automatism, in epileptics or sleepwalkers, can constitute an acceptable defence.
Infanticide is a defence when a child less than a year old is killed by its mother, who is ìsuffering from a mental imbalance attributable to the effects of giving birth or to the consequent lactationî.

Mental disorders which can contribute to homicide include:

• personality disorder.
• Alcohol and drug misuse.
• Psychoses, usually with delusions: depressed people may kill their children or other close relatives because of a delusion that they are going to suffer an even worse fate. Psychosis may lead to homicide through paranoid delusions; even here, the victim is often known; stranger killing (4), the type so feared by the general public- or at any rate so prominent in the media- is rare. Puerperal psychosis accounts for some, but not all, cases of infanticide.
• Morbid jealousy.
• Learning disability, in which frustration may be expressed by violence.
• Epileptic automatism: this is rare.
• Automatism during sleep: individuals prone to sleepwalking or night terrors occasionally kill during sleep. This rare defence is hard to prove.
• Organic brain disease.
  

Fitness to plead. It has always been recognised that the accused person has to have a basic understanding of the legal process in order to have a fair trial. Standard tests have grown up in order to determine whether he is or is not ìfit to pleadî. The grounds for being unfit to plead are inability to:

• understand the charge
• give instructions to a lawyer about his defence
• understand the difference between pleading guilty and not guilty
• challenge a juror
• follow the proceedings of the case in court
  

Psychiatric reports will be important in helping the court to determine the question of fitness to plead. If the person is found unfit, then a ìtrial of factsî follows. If it is found that the person did do the offence, then the court can dispose of the case by making an order, for example, for admission to hospital, similar to a section 37 of the Mental Health Act, with or without a restriction order.

If the patient goes to hospital and receives treatment and improves and becomes fit to plead, there is provision for them to be brought back to be tried by the court in the normal way.

The question of fitness to plead used to come up only rarely, and in the most serious cases, because if a person was found unfit to plead, they were sent to a Special Hospital without limit of time.

However, in recent years, the court has had flexibility in how it ìdisposesî of such cases, including community disposals and absolute discharge with no order. It seems, perhaps unsurprisingly, that the question of fitness to plead is now raised more frequently by the defence in a range of much less severe cases.

Rape Rape is sexual intercourse with a person who does not consent. Many cases are probably not reported to the police. Most rape victims are women, but male rape is an increasingly recognised problem.

Victims of rape may develop psychiatric disorders, such as post-traumatic stress disorder or sexual dysfunction. Sympathetic treatment in special Sexual Assault Centres can help to reduce the distress associated with reporting this crime, which may require intimate examinations to obtain evidence.

Various psychiatric classifications of rapists have been proposed in the past (violent, sadistic, etc) but are not now regarded as helpful: rape is an offence not an illness. If assessment is requested, the offender should be assessed in a standard way. Personality disorder, substance misuse and low intelligence are often found in rapists; mental illness is infrequent.

Antilibidinal drugs may be used in the management of rapists. However, this is a very difficult area medico-legally, lest the prescriber be blamed for any re-offending. If it were to be considered, it would only be as part of an overall package of offender management.

Arson Arson is taken very seriously by the criminal justice system, for obvious reasons. Occasionally, one may see a patient who has done a string of minor offences, and the system appears to have bent over backwards to keep them out of prison. If they do an arson, even one which does not have serious consequences, the attitude of the justice system can immediately become very different.

Arson may be done by

• Criminals, for example obtaining insurance money or concealing evidence of another crime.
• Psychotic patients motivated by delusions.
• Those with sociopathic personality and/or low intelligence who start fires for excitement, sexual stimulation or revenge. They often repeat the offence and may require secure detention.
• Children and adolescents with conduct disorder
  

Shoplifting The law does not distinguish shoplifting (theft from shops) from other kinds of theft, but it has been studied separately by psychiatrists. It is predominantly a crime of women. Types include:

• Straightforward theft.
• Psychiatric disorders including depressive illness (especially in middle-aged women), mania, schizophrenia, dementia, and learning disability.
• Absent-mindedness due to medical conditions such as epilepsy or hypoglycaemia, or prescribed drugs such as benzodiazepines.
• Addicts may steal from shops in order to fund their habit.
  

TREATMENT: GENERAL CONSIDERATIONS If a clearly identified mental illness appears directly related to the offending behaviour, the prognosis could be very good. For example, a man with schizophrenia who smashes up a television shop because he believes it is transmitting harmful rays will be unlikely to repeat this behaviour if his delusions resolve with treatment.

In other cases, mental disorder may co-exist with offending behaviour without being a significant causative factor, so that treatment of the disorder has little impact on the behaviour.

Substance misuse is very common among offenders. If, for example, a chronic alcoholic can be rehabilitated, he will be less likely to commit drunkenness and public order offences. Many prisons run AA groups for this reason. However, it is not always appropriate to remove a person from the criminal justice system on the grounds of substance misuse alone. Motivation to stop substance misuse may appear higher before an impending court appearance than later proves to be the case.

Psychological or behavioural treatments have been tried, irrespective of the presence of mental disorder, for a variety of habitual offenders, for example those convicted of car theft, ìroad rageî and assault. Few if any of these treatments have been shown to be effective in randomised controlled trials, and they tend to be regarded cautiously by psychiatrists. If they are to be provided, prison psychology services, probation or social services are the best source.

FACILITIES FOR MENTALLY DISORDERED OFFENDERS

Forensic psychiatry services. There has been a move away from thinking about forensic psychiatry mainly in terms of special inpatient units. Well-developed community forensic psychiatry services will now be characterised by a multidisciplinary, team-based approach, including:

• Consultant forensic psychiatrist, and junior doctor(s)
• Community psychiatric nurse and social worker
• Psychology

They will provide a range of services to Courts and Prisons, see referrals from general psychiatry colleagues and work closely with Probation. They will carry a caseload of outpatients. They may be based partly at a regional Secure Units, see below.

Regional Secure Units Regional Secure Units (Ruses) have been set up around the country, in line with current policy to expand the number of ìmedium secureî beds in each health district, so that the majority of psychiatric patients with violent behaviour, and of psychiatrically disturbed offenders, can receive treatment locally and only the most dangerous sent to Special Hospitals.

A typical RSU might have twenty beds, under the supervision of a consultant forensic psychiatrist and associated multidisciplinary team. Inpatient beds are frequently full, with pressure to accept referrals of ìdifficult to manageî (not necessarily forensic) patients from general psychiatric services. Such patients can be difficult to contain in modern psychiatric wards, which frequently lack intensive care beds .

Prison Medical Services Just as most mental disorder in the community as a whole is managed in primary care, so most mental disorder among prisoners has been managed by the Prison Medical Service. There are moves to make health care in prisons part of the general NHS, and increasingly NHS purchasers (currently known as Primary Care Trusts, though changes in nomenclature and organisastion are frequent) are being given responsibility for health care in prisons.

From the point of view of mental health care, this is highly desirable. If a patient with mental health problems enters prison, it is desirable that knowledge about his diagnosis and treatment should follow him in; conversely, a patient with mental health problems being managed in prison, should be able to have this management continued when he is released.

Integrating prison medical services within the general NHS will be likely to help to reduce the discontinuities in mental health care on reception into or discharge from prison, which have been frequent under the arrangement of having a separate prison medical service.

Because of the high rates of mental disorder in prisons, most prisons also have regular input from general adult and/or forensic psychiatric services. They will advise on diagnosis and management, either in the general wings or the prison hospital. In some units, there are dedicated facilities, set up by mental health services, and staffed and managed by them.

Compulsory treatment under the Mental Health Act 1983 is not, however, permitted in prisons. Sometimes it is necessary to transfer an inmate to psychiatric hospital, not necessarily under conditions of security, and the psychiatrist is able to assist in placement. There are appropriate sections of the Mental Health Act, regarding both sentenced (s47) and remanded (s48) prisoners.

As previously indicated, surveys of prisoners indicate that up to 50% or more can be diagnosed as some sort of mental abnormality. Sociopathy and substance misuse are the main diagnoses but learning disability, functional psychosis, organic brain disease and epilepsy are also found in excess. In some cases this disorder has not been recognised. Others are in prison because no psychiatric hospital place can be found for them. However the presence of certain psychiatric disorders, for example personality disorder/substance misuse/treated chronic mental illness, does not necessarily mean that prison is inappropriate.

Diversion Schemes In some Magistratesí Courts, regular attendance by psychiatrists or other trained staff allows psychiatrically disturbed persons coming before the Court to be diverted as appropriate from the criminal justice system into the health care system.

Diversion also happens at an even earlier stage, for example the custody sergeant at a police station may ask the police surgeon to examine an arrested person and, if a mental disorder is present, the help of local psychiatric services is sought.

The use of section 136 of the Mental Health Act also assists: it provides for someone who is disturbed in a public place to be taken to a place of safety for an assessment of their mental health.

Social and Probation Services These services have a close relationship with forensic psychiatry, including:

• Social and probation reports on offenders before the court.
• Resettlement of offenders.
• Probation and bail hostels.
  

For example, a mentally disordered person convicted of a crime may be put on probation, with psychiatric treatment as a condition of this. Failure to cooperate with treatment would be a breach of the probation order and result in the offender being brought back before the court.

This has sometimes been criticised as making psychiatry part of the criminal justice system. There would then, for example, be concerns about matters said in medical confidence to a doctor being potentially made known to the criminal justice system.

For minor offences, probation with a condition of psychiatric treatment has fallen out of favour for this and other more practical reasons: it would place mental health services in an impossible situation if they had to inform probation every time a patient did not, for example, collect a prescription. For more serious matters, the advantages can outweigh the disadvantages, and it is still used.

Primary Care Many offenders, especially released prisoners, may not be registered with a GP. This situation often adds to the difficulties of providing adequate medical care for this population, with its high rate of both physical and psychiatric illness.

Special Hospitals exist for treatment of patients with mental disorder, mainly psychosis, sociopathy or learning disability, who have committed violent crimes.
They comprise Broadmoor, Rampton and Ashworth in England, and Carstairs in Scotland. All patients are compulsorily admitted and detained under the Mental Health Act 1983, the majority from the courts, some from prisons or psychiatric hospitals. Violence to others, sex offences and arson are frequent reasons for admission.

Prospective admissions are assessed by Special Hospital staff, the main criteria being the presence of mental disorder and a ìgrave and immediateî risk to others. Most patients stay several years but about 50% eventually become fit for transfer to a local psychiatric unit in preparation for discharge to the community.

These hospitals have been staffed jointly by prison and health staff. There has been some confusion over whether how much of their purpose was care, rather than merely confinement. Recently, there have been moves to bring the Special Hospitals within the mainstream of health services, so that, for example, at the time of writing, Broadmoor Hospital is now part of West London Mental Health Trust.

Case Example

An unemployed man aged 38 presented himself to Casualty with the complaint of ìhearing voicesî. He admitted to recent drug use, and the likely diagnosis seemed drug-induced psychosis. He was admitted to a psychiatric ward informally, and rapidly improved with oral antipsychotic medication, but discharged himself before a full assessment had been made.

He did not attend follow-up, but presented again with similar symptoms shortly afterwards. On this occasion no beds were available and he was sent home with medication. Two weeks later, his consultant was surprised to receive a request from the local Magistratesí Court for a psychiatric report ìto assist in sentencing for a number of motoring offencesî.

It emerged after obtaining old notes that this man had been brought up in a large and chaotic family, of long-standing criminal tendencies, and had been subject to a mixture of neglect and abuse. He had spent his life taking, selling, repairing and even living in cars, and had multiple convictions for vehicle offences; none of a variety of sentences had influenced this behaviour. His only psychiatric history was the complaint of hearing voices during his last term of imprisonment; he had been transferred to hospital, only to abscond shortly afterwards. His probation officer indicated to the psychiatrist that the Court was very keen for him to be taken on for medical treatment, as they felt that other disposals would be ineffective.

At interview, residual psychotic symptoms were still apparent, but resolving. The man was frank about his drug use, and also about his intentions to continue with his offending behaviour.

The psychiatristís report indicated that his personality appeared to have been damaged by his unsatisfactory upbringing, and that he continued to have a psychotic illness, partly due to illicit drug use and partly due to the stress of impending imprisonment.

The court accepted the psychiatristís recommendation of a community disposal, with the condition of psychiatric treatment. It also imposed a suspended prison sentence. The patient accepted depot antipsychotic medication, which seemed to help the psychosis, but he continued to offend. He therefore breached the terms of his suspended sentence, and was imprisoned.