Mental Illness, Offending and Substance
About this leaflet
This leaflet is for members of the public who
want to know more about mental illness, offending and substance
We describe what is meant by mental
disorder, offending and substance misuse and how often they are
seen together. Also we will talk about treatments and other
sources of help. We examine whether people with mental illness
are more likely to commit violent crimes.
Offending and mental health
Mental illness is sometimes called a ‘mental
disorder’. This includes schizophrenia, bipolar disorder,
drug-induced psychosis, personality disorder, depression, anxiety
and post-traumatic stress disorder. These are just some examples of
The branch of psychiatry dealing with the
assessment and treatment of offenders with mental health problems
is called ‘forensic psychiatry’.
How common are mental health problems in
Studies have found that mental health problems
are much more common in prisoners than in the general population.
As much as 9 out of 10 prisoners report some kind of mental
health problem and the most commonly reported symptoms in prisoners
are sleep problems and worrying.
What types of crimes are committed by people with
The types of crime committed by people with
mental illness are no different from the crimes committed by
people who do not have mental illness.
What happens to mentally disordered
Mentally disordered offenders still go through
the criminal justice process as anyone else would. However, there
are measures in place to help people with mental illness. There are
assessments to identify people who would be best helped in
hospital. The Courts can also ask for a psychiatric report to help
them decide on the best course of action.
Sometimes offenders with a severe mental
illness are sent to hospital rather than prison to serve their
sentence. This decision depends on how severe their mental illness
is. People with less severe mental health problems can get
help in prison from mental health ‘In reach’ teams.
What treatment is available?
This may include medicines or psychological
treatments to reduce criminal behaviour and to help people
understand their mental illness.
The programmes currently running in prisons
- Reasoning and
- Anger Management
- Cognitive Self Change
- Sex Offender Treatment.
Substance misuse and mental illness
Substance misuse is the taking of a drug or
alcohol in such a way that it leads to harm. Examples of harm
include: addiction, debt, physical harm, criminal actions and
The drugs used may be:
- Legal substances (e.g.
- Illegal substances, such as
opiates (e.g. heroin), stimulants (e.g. cocaine, crack,
amphetamines and ecstasy) and cannabis
- Prescription drugs used in a
way not intended by the doctor (e.g. benzodiazepines).
If someone has a mental illness along with a
substance misuse problem, they are said to have a ‘dual
Is there a link between mental illness and substance
Research shows that substance misuse may cause
or increase symptoms of mental illness. On the other hand, mental
illness may lead someone to abuse substances. They may want to
block out their symptoms or the side-effects of medication. They
may have difficulties in sleeping, feel lonely or simply wish to
boost their self-confidence.
People with a dual diagnosis have other
problems including being lonely, homeless, having a history of
abuse and are more likely to get into trouble with the police.
Depression, anxiety and schizophrenia are more
likely to be linked to substance misuse. The drug use can stop
people making a full recovery. It is also more likely to lead
to becoming unwell again or to have to be
re-admitted to hospital.
How common are these problems?
The UK has one of the highest levels of drug
misuse in Europe.
About a quarter of people in the UK drink more
alcohol than they should. The amounts drunk have doubled over the
last 50 years and are still rising. Physical health problems
caused by alcohol have doubled in the last 10 years. Deaths have
doubled over the last 15 years.
About 35% of people aged 16-59 have used
illegal drugs in their lifetime. Cannabis is the most commonly used
Dual Diagnosis - substance misuse problems are
common among people in mental health services. The number of people
with a mental illness and who misuse substances has increased by
62%, in particular for those suffering from schizophrenia.
What are the consequences?
People with dual diagnosis do worse than those
with mental health problems alone. They are also more likely to be
admitted to hospital, to self-harm and commit suicide.
The combination of having a mental illness,
substance misuse and not taking medication can increase the risk of
violence toward others. However this makes up only a small amount
of violent acts.
Drug-related violent crime
This can be split into:
- violence from effects of the
- violence from interaction
between a mental illness and drug use
- violence related to stealing
to get money from drugs
- fighting between drug users,
Prisons, mental health and drugs
Unfortunately, dual diagnosis is often seen in
people in prison. The criminal justice system tries to help people
with drug problems through prison-based drug treatments and
community punishments which include drug rehabilitation
Other sources of help
Anonymous Phone: 0845 769 7555
They have objectives to improve the lives,
mental health and wellbeing of offenders and enhance the lives of
people with mental health problems through employment.
Provides information and support for everyone with mental health
problems or learning disabilities.
Promotes the views and needs of people with
mental health problems. Phone: 0845 766 0163.
Anonymous Phone: 0300 999 1212.
reduction charity who work with disadvantaged people, offenders and
those at risk of offending
Nacro's helpline offers specialist support and
advice to prisoners, ex-offenders and their families on 020 7840
Mental Health Primary
Care in Prison
A guide to mental ill health in adults and
adolescents in prisons and young offender institutions.
1. Peay, J
2007. Mentally disordered offenders, mental health and crime,
in MacGuire M. et al. (eds) the Oxford Handbook of Criminology, 4th
ed. Oxford: Oxford University Press
2. Advisory Council
on the Misuse of Drugs (2006) Pathways to Problems: Hazardous use
of tobacco, alcohol and other drugs by young people in the UK and
3. NHS Information
Centre (2008) Statistics on Alcohol: England 2008, London, NHS
4. Frisher, M., Crome
I., Macleod, J., Millson, D., and Croft, P. (2005) Substance abuse
and psychiatric illness: Prospective observational study using the
General Practice Research Database. Journal of Epidemiology and
Community Health, 59, pp.847–850.
5. Swanson, J.,
Borum, R., Swartz, M., and Hiday, V. (1999) Violent behaviour
preceding hospitalisation among persons with severe mental illness,
Law and Human Behaviour 23, pp.185–203.
Expert Review: Dr Ali Ajaz and Dr Paula
Series Editor: Dr Philip Timms, chair, Royal College of
Psychiatrists' Public Education Editorial Board
This leaflet reflects the best available evidence available at
the time of writing.
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