Schizophrenia is a serious mental disorder that distorts a person’s behaviour, ideas and moods. People who have it may hear voices, see things that aren't there or believe that others are reading or controlling their minds.

About 1% of all people develop schizophrenia. If one parent has schizophrenia, the child has about a 10% chance of developing it. It can affect anyone at any age but, mostly, symptoms begin between the ages of 16 to 25. For men, symptoms usually start in the late teens to early 20s. In women, symptoms often start later - mid-20s to early 30s.


No one is sure what causes schizophrenia, but a person's genetic makeup and brain chemistry probably play a role. Studies have explored the role of injury to the developing brain and looked at a range of possible causes, such as viral infection during pregnancy or birth complications, but there are no clear answers.

Some illicit drug use can result in symptoms similar to those of schizophrenia. In those people predisposed to mental illness, illicit drugs may trigger or worsen schizophrenia or other psychotic disorders (without actually being the cause of the illness).

Alternatively, someone who is in the early stages of psychosis may be using marijuana, for instance, to cope with their symptoms.


Schizophrenia is often referred to as a psychotic illness. ‘Psychosis’ describes the symptoms associated with losing touch with reality. Psychotic symptoms may occur suddenly or develop slowly over a period of months or years. Symptoms of schizophrenia may also be found in other illnesses.

Symptoms can include one or more of the following:

  • Hallucinations – the person may hear, see, taste, smell, or feel things that are not there. ‘Hearing voices’ no one else can hear is the most common hallucination. The voices may be threatening, frightening or commanding the person to do harmful acts; however, some people hear reassuring or neutral voices.
  • Delusions – the person may develop unusual and steadfast beliefs. They may think they have ‘special powers’, that they are being watched or spied upon, or that their thoughts are being broadcast to the world. Such delusions cannot be changed by logical argument or contrary evidence.
  • Disordered thoughts – the person may have trouble connecting ideas into a logical sequence, or may jump rapidly from one topic to another, so that it is difficult for the person to hold a conversation. This may also be accompanied by inappropriate emotional responses (words and moods do not match), and the person may laugh when speaking of a serious or frightening event.
  • Lack of motivation – the person may find doing ordinary tasks such as washing, cooking, or planning ahead very difficult. Solving everyday problems becomes a chore.
  • Social withdrawal – the person may seem unaware of their illness or other people’s feelings. Their concentration and memory may be poor, and they may find it difficult to communicate as they would normally.
  • Changes in mood – the person may appear anxious, panicky, depressed or in an abnormally good mood.
  • Their emotions may be ‘flattened’ – for example, the person may appear quite ‘wooden’ and unable to express joy or sorrow, or they may have a preoccupation with death.
  • The person may also have impaired thinking, problems with remembering and a lack of insight.


Schizophrenia can usually be diagnosed if:

  • You have at least two of the following symptoms:Your symptoms have had a significant impact on your ability to work, study or perform daily tasks.
    • delusions
    • hallucinations
    • disordered thoughts or behaviour
    • negative symptoms, such as a flattening of emotions.
  • You have experienced symptoms for more than six months.
  • All other possible causes, such as recreational drug use (or other health conditions such as bipolar disorder) or depression, have been ruled out.


In schizophrenia, several chemical pathways in the brain can be interrupted and information processing is poorly controlled. This disruption leads to a wide variety of problems, which must be treated in various ways. The recommended treatment approaches for schizophrenia include:

  • Early diagnosis and treatment. 
  • A comprehensive psychosocial education/treatment programme, including education and support for the person and their family, counselling, stress management and supported employment opportunities. People with schizophrenia benefit enormously when their families, friends and workmates understand the illness and are educated about the ways to best provide help should it be needed.
  • Ongoing support (including housing where appropriate), monitoring and development of a relapse prevention plan treatment for those at risk of repeated relapse and hospitalisation.
  • Appropriate use of antipsychotic medicines can relieve many of the symptoms, but it can take several tries before finding the right medicine. Relapses can be reduced by staying on the medicine for as long as the doctor recommends.

Antipsychotic medicines

Antipsychotic medicines are the main group of medications used to treat schizophrenia. They are classified as “typical” or “atypical”.

  • Typical antipsychotics are the traditional or first-generation antipsychotics such as haloperidol and chlorpromazine.
  • Atypical antipsychotics (also known as second generation antipsychotics), include medications such as risperidone, olanzapine and quetiapine. They have become popular as they are less likely to cause extrapyramidal adverse effects.
  • Antipsychotics work by blocking receptors in the dopamine pathway.
  • Both groups need careful monitoring as they are associated with increased risk of diabetes, stroke and cardiac death.
  • It is important to keep blood pressure within the normal range, eat healthily, see your doctor or GP regularly and keep physically active to minimise these risks.

Learn more

Schizophrenia diagnosis  NHS Choices, 2012
Schizophrenia Medline Plus, National Institute of Health, 2014
Transforming understanding and treatment of mental illness National Institute of Mental Health
Genetic risk – diseases that run in families Learn Genetics (Genetic Science Learning Centre), University of Utah, USA, 2015

Credits: Editorial team.