Fact Files

What is severe mental illness?

What is a mental illness?

Everyone's mental health varies from time to time - mental health problems are three times more common than cancer. People who have a mental illness experience a range of symptoms. For example, some may experience anxiety as a generally uneasy feeling, while for others it can be so severe it disrupts their whole life.
Mental illness in England costs over £77 billion a year when the costs of mental health care, loss of earnings and poor quality of life are combined. People with a mental illness have the highest levels of unemployment of any disabled group

What is severe mental illness?

There is no universal understanding of what severe mental illness is, because it tends to be seen differently by the person experiencing it, their family and friends and doctors. The term usually refers to illnesses where psychosis occurs. Psychosis describes the loss of reality a person experiences so that they stop seeing and responding appropriately to the world they are used to.

Schizophrenia, manic depression, schizo-affective disorder and clinical depression are the severe mental illnesses explained in the accompanying media briefing. This does not mean that other conditions are not regarded as serious. People's diagnosis may change because:

  • their symptoms tend to change over time
  • they may have more than one condition at the same time
  • their underlying condition is 'masked' by the use of street drugs or alcohol
  • distinguishing between psychotic disorders is not always an exact science.

Signs and symptoms of psychosis

Violence is not a symptom of psychosis or mental illness. The Rethink media briefing on violence provides more facts about this common misconception. The two most common types of symptoms are hallucinations and delusions -

  • Hallucinations

Having hallucinations means that someone may hear their own thoughts as if they are coming from a source outside their own body. They may also see, smell or taste things that appear to be real but which are not being experienced at that time by anyone else.

  • Delusions

People who have hallucinations often try to find an explanation for them, and may attribute them to beliefs that others may see as strange and which are called delusions. They may believe that the voices they can hear are coming from the television, speaking directly to them, or coming from someone who is plotting against them. The voices may be critical or abusive. This kind of distorted thought pattern may cause very severe anxiety called paranoia.

What causes a psychotic illness?

The exact causes are not known. There may be a genetic vulnerability in some people that can be triggered by environmental and emotional factors such as bereavement, moving home or a breakdown in relationships. Yet there is no obvious genetic link in other people. It is now known that families do not cause mental illness, though they can play a key role in helping the person recover.

Getting the right help at the right time gives people the best chance of recovery.

How many people experience psychosis?

At any one time around 630,000 people in England and Wales are in contact with a specialist mental health service. Around 50,000 people are treated under a Section of the Mental Health Act very year. About one in hundred people experience at least one acute episode of psychosis at some point in their lives. Some people will only experience one 'psychotic episode' and about a quarter of people make a full recovery. Others will have recurring periods of problems, perhaps at times of particular stress in their lives. The majority have long periods during which they are quite well, while some remain very disabled.

How do people recover from severe mental illness?

Many people who experience severe mental illness can and do recover a meaningful and fulfilling quality of life. Treatments and support that address all the person's needs are need for the best chance of recovery. This includes medicines, talking therapies, appropriate housing and financial independence.


1 Creating Accepting Communities, Mind, 1999
2 The Economic and Social Costs of Mental Illness, Sainsbury Centre for Mental Health, 2003
3 Office for National Statistics 'Survey of Psychiatric Morbidity in Great Britain, Report no 3, Economic Activity & Social Functioning of Adults with Psychiatric Disorders', Stationery Office, 1995
4 Reforming The Mental Health Act, Stationery Office, 2000
5 Statistical Bulletin,`In-patients formally detained in hospitals under the Mental Health Act 1983 and other legislation, England: 1991-92 to 2001-02, Department of Health, 2002

2) Schizophrenia, manic depression, schizo-affective disorder and clinical depression

Schizophrenia, manic depression, schizo-affective disorder and clinical depression are the severe mental illnesses explained here. This does not mean that other conditions are not regarded as serious. For more details of other related publications that that explain this issue, see the list at the end of this briefing.

(i) Schizophrenia

Schizophrenia is not "split personality." It represents a breakdown of communication between different parts of the brain. The symptoms of schizophrenia include:

  • hallucinations and delusions
  • slowness to think, speak or move
  • disrupted thought patterns
  • inappropriate emotional responses such as laughing at sad situations
  • trouble in communicating thoughts and feelings.

During an acute psychotic episode, the person may experience panic, anger with over-activity and periods of complete withdrawal and self-neglect.

Any or all of these can leave the person experiencing them socially isolated and they may withdraw from the world around them. They may also experience depression as a result of these difficulties and learning to cope with them.

Facts and figures: schizophrenia is estimated to cost the NHS around £1 billion, or 5% of its total budget, more than any other mental illness. About one third of 'street homeless' people in the UK are thought to have a diagnosis of schizophrenia.

(ii) Manic depression

In manic depression, also known as bipolar disorder or bipolar affective disorder, people experience episodes of both mania (highs) and depression (lows), often for lengthy periods and sometimes with many years between episodes.

Periods of mania can lead to increased energy, over-activity, racing thoughts and speech, reduced sleep, and loss of normal social inhibitions. People may go on spending sprees or start unrealistic projects.

For some people experiencing mania there is irritability, or feelings of anger and inappropriate aggression rather than high mood. Self-neglect - in extreme cases, forgetting to eat, drink or wash - can result in severe dehydration or starvation.

Facts and figures: around one in a hundred people will experience manic depression in their lifetime. There are 370 hospital admissions per 10,000 of the population per year for manic depression - yet only 3% of these are for first-time admissions, reflecting the recurrent nature of the illness.

(iii) Schizo-affective disorder

Schizo-affective disorder is the medical term used where the symptoms of depression or mania and symptoms of schizophrenia are present at the same time or within a few days of each other. This is quite common and usually the schizophrenia symptoms are more obvious. Where the mood disorder is more pronounced the condition is more often called depressive or manic psychosis.

Facts and figures: About one in every two hundred people (1/2 percent) develops schizoaffective disorder at some time during his or her life. Schizoaffective disorder effects more women than men, and the average age of onset is usually in the late 20s. As many as 20% of people with severe and persistent mental illness may have schizoaffective disorder.

(iv) Clinical depression

In clinical or severe depression the lows are much more severe and persistent than in common depressions. People who are effected may also experience psychosis, usually with strong feelings of guilt or persecution. They may hear critical voices in their head. The symptoms of severe depression include:

  • a low mood
  • loss of interest in life or pleasurable pursuits
  • reduced attention and concentration levels
  • thoughts of guilt and worthlessness
  • low self-esteem and reduced energy levels.

These can lead to feelings of hopelessness and suicidal thoughts.

(v) Physical symptoms include:

  • loss of appetite and weight
  • digestive problems
  • disturbed sleep patterns
  • reduced activity and interest

Facts and figures: around one in 20 people will experience clinical depression at any one time - by 2020, the World Health Organisation estimates it will be second only to heart disease as the second largest international health burden.


1 Guidance on the use of newer (atypical) antipsychotic drugs for the treatment of schizophrenia, National Institute for Clinical Excellence, June 2002
2 Kavanagh S, & Opit L, 'The prevalence of schizophrenia amongst the homeless and prison populations in England', Personal Social Services Unit, 1994
3 World Health Organisation, 1995
4 Manic Depression Fellowship
5University of California (UCLA) Neuropsychiatric Institute (NPI) website.
National Alliance for the Mentally Ill (NAMI) Vermont website

3) Personality disorder

What is a personality disorder?

Each of us has a personality or group of characteristics which influence the way we think, feel and behave, and makes us a unique individual. Someone may be described as having a personality disorder if their personal characteristics cause regular and long-term problems in the way they cope with life and interact with other people.

It is possible that some people with these disorders never use mental health services. This diagnosis is estimated to affect around 10 per cent of the population.

What causes personality disorders?

The causes are not fully understood but two main factors seem to be:

  • experience in early childhood e.g. when a child is consistently deprived of affection or bullied.
  • inherited personality traits, which may be linked to the way the brain processes serotonin.

What are the different types of personality disorder?

There are 10 recognised forms of personality disorder and only one of these - severe anti-social personality disorder - is linked to increased levels of violence. These are some of the most common types:

  • Paranoid personality disorder - when someone is excessively suspicious of other people.
  • Schizoid personality disorder - when someone is extremely withdrawn and is not interested in friendships or in social relationships.
  • Avoidant personality disorder - when someone is excessively self-conscious, afraid of being challenged, criticised or rejected.
  • Obsessive compulsive disorder - when someone is obsessed with orderliness and control, often in work and in relationships. Sometimes people with psychotic conditions will have obsessions or compulsions.
  • Borderline personality disorder is associated with the inability to maintain personal relationships, unstable moods and emotions. People with a borderline personality disorder may appear overly argumentative, sarcastic and be quick to take offence while hating being alone.
  • Anti-social personality disorder, or psychopathic disorder - when someone is extremely selfish, impulsive, insensitive to other people's feelings and feels no guilt or shame about actions which harm others.

How is personality disorder diagnosed and treated?

As with mental illness, there are no tests - like analysing a blood sample to check whether personality disorder is present. Psychiatrists look for signs and characteristics and may use classification systems to help them identify groups of traits as particular disorders. A range of therapies is available for personality disorders, including psychological treatments and drug therapy.

What separates a personality disorder from a personality trait is its unshakeable consistency and resistance to change. In Rethink's experience, a diagnosis of personality disorder is sometimes given inappropriately to people who:

  • are 'non-compliant' or difficult to engage in treatment
  • do not respond to most treatments
  • are difficult to 'manage' in settings like a hospital ward
  • are difficult to diagnose

What is Dangerous Severe Personality Disorder (DSPD)?

This is a term invented by British civil servants to describe a small group of people who have a severe personality disorder (usually anti-social PD) and are thought to be dangerous. It is not a medical diagnosis or legal category and few mental health workers accept that it is a real category. Because most people in this group are regarded by doctors as 'untreatable' they may not be detained under the Mental Health Act 1983 in certain circumstances.

Through the draft Mental Health Bill, the government is planning to introduce a form of preventative detention for people with a dangerous and severe personality disorder who show a propensity to violence, even though no criminal conviction may have been secured. The exact numbers of people affected by these plans are unknown. The government has decided to pilot and evaluate the assessment process and treatments available for people who have a DSPD before taking final decisions. Pilots are already underway in a number of settings, including: Rampton Hospital, Whitemoor Prison, Frankland Prison and Broadmoor Hospital.

Estimates suggest that several thousand people could be subject to the orders, some of who are presently living in the community, some in prison and some in Special Hospitals.

With such a weak understanding of personality disorder, there is concern that some people will be misdiagnosed, shifting between labels, treatments and care plans. Once diagnosed with a severe anti-social personality disorder, there is a danger that a person will be doubly stigmatised and labelled as untreatable.

4) Suicide

On average, two people with mental health problems commit suicide every day (Department of Health).

Around 10 per cent of people diagnosed with schizophrenia will die an unnatural death, usually suicide, compared to a suicide incidence in the general population of 1 per cent.

Suicide is defined as the intentional taking of one's own life.

Some coroners are reluctant to return a verdict of suicide in the case of a person with a mental illness, arguing that the person's intentions could not be clear. Official figures may, therefore, underestimate the number of people with a mental illness who take their own lives. A 1999 NSF (now Rethink) analysis of 589 unnatural deaths of people with schizophrenia over an eight-year period, One in Ten, found that coroners were more likely to ascribe a verdict of suicide to deaths by hanging, trains and burns. Deaths where the person was found to have jumped/fallen or drowned were more likely to be categorised as open verdicts. Men were more likely to use one of the methods likely to receive a verdict of suicide, while women were likely to use one of the methods associated with an open verdict. Women in general, and in particular women from the Asian ethnic minority, were more likely to use burning as a method of suicide.

The government's Our Healthier Nation report targeted suicides among people with a severe mental illness for a 20 per cent reduction on their 1996 levels by the year 2010, saving 4,000 lives in total. Suicide rates have fallen generally over the last 15 years but not among men aged 15-44. There were 4,522 suicides and undetermined deaths in 1997. One in 100 young women aged 15-19 will attempt suicide.

The National Confidential Inquiry into Suicide and Homicide by People with a Mental Illness (1999) found that 22 per cent of suicides could have been prevented. More could have been done in two-thirds of cases. Sixteen per cent of suicides were in-patients. The inquiry called for wards to be redesigned to allow easier observation and for the replacement of structures that could be used for hanging, the most common form of in-patient suicide. There were 4,522 suicides and undetermined deaths in 1997. One in 100 young women aged 15-19 will attempt suicide.

People with schizophrenia are not often driven to take their own lives by "voices" or by delusions, such as flying from a high building. People with a severe mental illness are likely to commit suicide for similar reasons to everyone else - the collapse of personal relationships, the loss of a job or home and so on - all factors likely to be created by the mental illness itself. The Office for National Statistics says that suicide rates are linked to poverty levels. Local authorities in which suicide rates are significantly high are characterised by high levels of deprivation. Local authorities with significantly low suicide rates tend to be those with low levels of deprivation. There is also a positive relationship between schizophrenia and poverty.

Suicides are not inevitable and can be prevented. In the community, proper support, financial security, safe accommodation and useful occupation in day centres and sheltered work settings for those without paid employment can all help. In a hospital setting, where many suicides take place, staff need to be fully trained in risk assessment and the skills of prevention.

5) Violence

"While, of course, we must pay proper attention to the rights of people who are mentally ill, we must also make sure - this is why there has been such pressure to change the law - that the public are properly protected from people who may be mentally ill and a severe danger to the public even though they have not been convicted of a specific criminal offence."
Prime Minister Tony Blair. November 20 2002

"There has been no assessment of the effectiveness of community treatment orders on reducing the number of homicides because this is not the intended purpose of the orders as proposed in the draft Mental Health Bill."
Health minister Jacqui Smith November 7 2002

The context:

There is a perception amongst the general public that mental ill-health, particularly in its most severe forms such as schizophrenia, is linked to violence. That "perception" is being used by politicians to press for new mental health laws that would make it easier to detain people.

Rethink is a member of the Mental Health Alliance, which brings together over 50 organisations. They believe that, while a new modern Mental Health Act is needed, it should not be founded on a false understanding of mental health and violence.

Death is obviously the most serious outcome of a violent act. So are people with mental health problems the big "killers" in society? Each year:

  • 5,000 people die from NHS acquired infections
  • Over 3,000 people die on the roads
  • Around 300 of these people are killed by drunk or dangerous driving
  • 300 people are killed at work
  • Around 100 women and 100 children will be killed during domestic violence
  • Between 600 and 700 people are murdered - the result of "homicide" to use the legal term
  • Around 400 will involve someone abusing alcohol
  • Around 40 homicides will involve someone with a mental disorder
  • Around half of these 40 homicides - 20 each year - will involve someone with a mental disorder who was in touch with mental health services at the time.

The simple truth is that most violent, avoidable or preventable deaths have nothing at all to do with the 630,000 people who are today in contact with mental health services.

That is why the government's draconian proposals for reforming the Mental Health Act to "make sure ... that the public are properly protected from people who may be mentally ill" are unfounded and, as a result, will add to the stigma faced by people with mental health problems.

What will protect the public - and the up to 1,000 people a year with mental ill-health who kill themselves - are quality mental health services, open accessible and free from the stigma that now surrounds them.

6) Cannabis


Cannabis was reclassified on January 29 from a Class B to a Class C drug.

Rethink severe mental illness is concerned that:

  • the mental health risks associated with cannabis are not widely understood
  • the government's publicity campaign does not highlight these mental health risks
  • more resources need to be put into mental health warnings on the use of cannabis.


Rethink, formerly known as the National Schizophrenia Fellowship, is the charity for people who experience severe mental illness and for those who care for them. We are both a campaigning membership charity, with a network of mutual support groups around the country, and a large voluntary sector provider in mental health, helping 7,500 people each day. Through all its work, Rethink aims to help people who experience severe mental illness to achieve a meaningful and fulfilling life and to press for their families and friends to obtain the support they need.

On January 29, cannabis will be reclassified by the Home Office from a Class B to a Class C drug. The change is being accompanied by £1 million awareness campaign organised from the Home Office that emphasises that that cannabis will remain an illegal drug. The awareness campaign does not highlight the mental health dangers associated with cannabis use.

What are the mental health dangers?

There is a general consensus that use of cannabis by someone who has schizophrenia worsens the psychotic symptoms of the illness - paranoia, hallucinations and delusions. This is also true for people with bipolar affective disorder (manic depression) experiencing psychotic symptoms.

There is strong evidence from a wide range of sources that long term and short-term use of cannabis can "trigger" a psychotic episode or schizophrenia in people who are at high risk of developing schizophrenia - for instance, people who have close family members who have schizophrenia.

There is emerging evidence from a limited number of sources that long-term use of cannabis, particularly when use begins in early teenage years and continues into adulthood, can lead to people who should be at no or low risk of schizophrenia developing the illness.

What is being done about this?

The Home Office awareness campaign, which includes a four-week long radio campaigning beginning on January 24, a range of leaflets and posters aimed at young people, concentrates on the message "Cannabis is still illegal." None of the material we have seen mentions the impact of cannabis on mental health.

In late February, a health campaign organised by the Home Office will target 13-18 year-olds with a range of messages that will mention mental health, but only in passing. It is understood that just £50,000 of the £1 million total is being spent on general health awareness messages.

What should be done about this?

Rethink believes that young people are hearing that, as a result of this reclassification, cannabis is no longer regarded as a serious drug and that the police won't make arrests except in the most serious circumstances. Young people are getting the message that cannabis is risk-free.

A long-term, well-funded, innovative campaign aimed at publicising the real mental health risks associated with cannabis needs to be in place as soon as possible to counter this "risk-free" message.