Schizophrenia: symptoms, causes, diagnosis and treatment

The NHS says schizophrenia changes how a person thinks and behaves. The condition may develop slowly, and the first signs can be hard to identify as they often develop during the teenage years. Becoming socially withdrawn and unresponsive, or changes in sleeping patterns, can be mistaken for an adolescent phase.

People often have episodes in which symptoms are particularly severe, followed by periods when they experience few or no symptoms. The NHS classifies symptoms as positive symptoms, which are any change in behaviour or thoughts such as hallucinations or delusions, and negative symptoms, where people appear to withdraw from the world around them, take no interest in everyday social interactions and often appear emotionless and flat.

The NHS describes schizophrenia as a long-term mental health condition, often described as a type of psychosis. The NHS states that people with schizophrenia do not have a split personality, and that schizophrenia does not usually cause someone to be violent.

The NHS adds that most people who have psychotic episodes are not a danger to others. A first acute episode can be very difficult to cope with, for the person and for family and friends, and the person may become upset, anxious, confused, angry or suspicious of those around them. They may not think they need help.

The NHS says schizophrenia is usually treated with an individually tailored combination of talking therapy and medicine. Most people are treated by community mental health teams (CMHTs), which provide day-to-day support and treatment while ensuring you have as much independence as possible. During a first episode you should initially be referred to an early intervention team.

People with complex conditions are usually entered into a care programme approach (CPA), with an assessment, a care plan, a key worker and regular reviews. The care plan may include an advance statement or crisis plan and should include a healthy eating and physical activity programme and support for giving up smoking.

The NHS says the exact causes are unknown. Research suggests a combination of physical, genetic, psychological and environmental factors can make a person more likely to develop the condition. Some people may be prone to it and a stressful or emotional life event might trigger a psychotic episode.

On genetics, the NHS says it tends to run in families but no single gene is thought to be responsible. If an identical twin develops schizophrenia, the other has a 1 in 2 chance of developing it, and for non-identical twins it is 1 in 8, compared with about 1 in 100 in the general population.

• Differences in brain development, and possibly differences in neurotransmitters such as dopamine.

• Pregnancy and birth complications such as low birthweight, premature labour or a lack of oxygen during birth.

• Stressful life events such as bereavement, losing your job or home, divorce, the end of a relationship, or abuse. These do not cause schizophrenia but can trigger it in someone already vulnerable.

• Drug use. The NHS says using cannabis, cocaine, LSD or amphetamines can increase the risk of schizophrenia or psychosis, and that teenagers and young adults who regularly use cannabis are more likely to develop schizophrenia in later adulthood, with the risk possibly higher with stronger forms of cannabis.

The NHS says there is no single test for schizophrenia, and it is usually diagnosed after assessment by a specialist in mental health. A GP will ask about your symptoms and check they are not the result of other causes, such as recreational drug use. If schizophrenia is suspected, the GP should refer you to your local community mental health team, where a psychiatrist or specialist nurse carries out a more detailed assessment, including your personal history and current circumstances.

Most mental healthcare professionals use a diagnostic checklist. The NHS says a psychiatrist may consider related illnesses such as bipolar disorder or schizoaffective disorder, and you may also be assessed for post-traumatic stress disorder, depression, anxiety and substance misuse.

The NHS says the first signs often develop during the teenage years and can be mistaken for an adolescent phase. For children and young people with a first episode of schizophrenia, it says they should be referred urgently to a specialist mental health service: children and young people's mental health services (CYPMHS) for those up to 17, or an early intervention service for those aged 14 or over that includes a consultant psychiatrist with training in children and young people's mental health.

The NHS directs readers to NICE guidelines on psychosis and schizophrenia in children and young people for more information.

The NHS says that if you are experiencing symptoms of schizophrenia, you should see a GP as soon as possible, because the earlier it is treated the better. If you are worried about someone else, the NHS says people with schizophrenia may be reluctant to see a GP if they believe there is nothing wrong. If they have a care co-ordinator, contact them; the person may have a written crisis plan.

In a rapidly worsening episode, the NHS says you may need to go to A&E, where a duty psychiatrist will be available. If a person refuses help, their nearest relative can request a mental health assessment, and the social services department of your local authority can advise how. If you or someone else is in immediate danger, call 999.

The NHS says that if schizophrenia is well managed, it is possible to reduce the chance of severe relapses by recognising the signs of an acute episode, taking medicine as prescribed and talking to others about the condition. Your care plan will include the likely signs of a developing relapse and the steps to take, including emergency contact numbers.

Many charities and support groups offer help and advice, and the NHS says most people find it comforting to talk to others with a similar condition. Peer support from someone who has had schizophrenia and is now stable may be available through some services.

On the NHS, schizophrenia is assessed through a GP referral to a community mental health team or early intervention service, with crisis and home treatment teams for acute episodes. Most care is delivered through these specialist NHS services, with regular medicine review.

Some people choose a private psychiatrist for assessment or a second opinion. Private care should be coordinated with the NHS team and your GP, especially for medicine monitoring and crisis plans, so that everyone involved has the same information.