What is Schizophrenia?

Schizophrenia is a severe mental disorder characterised by breakdown of the process of thinking, of contact with reality and of emotional responsiveness. Usually this can involve delusions and hallucinations, particularly auditory, with the patient believing that their thoughts, sensations and actions are produced by forces outside of their control. It is one of the most common serious mental health conditions, with one in every hundred people experiencing at least one episode of acute schizophrenia. Re-occurrence of acute psychotic episodes thenn reclassifies the condition as chronic schizophrenia. A common misconception is to mistake schizophrenia for multiple personality disorder, although confusingly the word schizophrenia means 'split mind' in Latin, from the Greek skhizein ‘to split’ and phren ‘mind’. Onset of schizophrenia tends to be around 20 to 28 years of age in males, and 26 to 32 in women.

There are five main types of schizophrenia:

  • Simple - Features social withdrawal and other negative symptoms but no positive symptoms.
  • Residual - Features low level positive symptoms.
  • Disorganised or Hebephrenic - Disordered thought and speech. Onset in adolescence or young childhood
  • Paranoid - Hallucinations or delusions are present, but other symptoms such as disorganised thoughts are not present. Later onset than other forms.
  • Catatonic - Major motor disturbances, such as immobility.

The video below shows a young woman with schizophrenia. Her odd facial expressions and slurred speech are a side effect of the antipsychotic medicine she is taking. If you listen to her conversation you will notice that there is no consistent or logical structure to her thoughts.



The symptoms of schizophrenia are usually classified as either positive, representing a change in behaviour or thoughts, or negative, representing a lack or reduction in functioning. Defects in cognitive function such as memory and attention, along with anxiety and depression are also often present, leading to suicide in around 10% of cases.

Positive Symptoms

Positive symptoms include hallucinations and delusions. Hallucinations are most commonly auditory, and the voices heard by schizophrenics tend to be controlling (forcing the individual to do something against their will) and/or critical (of the person and their actions).

Delusions can range from 'normal' delusions about everyday life, to irrational paranoias, such as believing that something, or someone, is deliberately trying to mislead, manipulate, hurt or, in some cases, even kill you. Other delusions include delusions of grandeur or finding significance in otherwise insignificant everyday events.

Another positive symptom is disordered thoughts, where concentration and simple tasks may become extremely difficult . Schizophrenics can also believe that thoughts have been planted in their minds, are being removed from their minds, or can be heard or read by others. 

Negative Symptoms

Negative symptoms can be present much before an initial acute schizophrenic episode. They include a lack of or 'blunted' emotions, inability to experience pleasure, a reduction or total lack of motivation, and becoming increasingly untalkative. These symptoms can put stresses on relationships with friends and family.

There is also a third grouping of symptoms, the disorganisation syndrome, associated with chaotic speech, thought and behaviour.



The causes of schizophrenia are not fully understood, although most experts support the 'stress-diathesis model' of schizophrenia; which states that every individual has a certain vulnerability (or diathesis) to schizophrenia, which is determined by the combination of their biological, psychological and environmental factors. People with a high vulnerability to schizophrenia may not need a particaularly stressful event to trigger the condition, whereas people with a low vulnerability may need a very stressful event to occur to trigger the condition.

As the stress-diathesis model suggests, are many factors involved in the development of schizophrenia, including genetic, prenatal (infections), social (such as living in poverty or an urban environment), drug abuse, and ethnicity. If one of your parents has a history of schizophrenia, your chance of developing the condition is one in 10. This risk factor is 10 times higher than that of somebody with no family history of schizophrenia.

On a scientific level, the symptoms of schizophrenia are believed to be due to an increase in levels of a neurotransmitter, PET scan of brain with striatum highlighted in greendopamine, in certain areas of the brain. Increases of dopamine in the mesolimbic (motivation) areas of the brain account for the positive symptoms (the striatum, highlighted in green in the picture to the right, is a dominant part of the mesolimbic pathway). This was discovered via the effects of illegal drugs which increase dopamine, such as amphetamines and cocaine, which tend to produce psychoses indistinguishable from the positive symptoms of schizophrenia. However, this theory appears to be oversimplified as recent evidence suggests a role for serotonin and glutamate neurotransmitters in schizophrenia also. There is more about this subject on the How Do They Work? page.


Treatment of schizophrenia is not just limited to antipsychotics, although this is usually the first step. Cognitive behavioural therapy (CBT) is widely used, and has been proved to reduce positive symptoms. CBT is also used to alleviate related issues such as self-esteem and social functioning problems. If first-line treatments are not effective, electroconvulsive therapy is an option, whereby seizures are electrically induced in anaesthetised patients, which has been shown to alleviate symptoms of catatonic schizophrenia especially.

Related Links and References

Links providing information on schizophrenia and the associated area:

Mind mental health charity schizophrenia page: 


Very helpful online versions of the charity's booklets.

NHS Choices schizophrenia page:


In depth UK information on schizophrenia. Make sure not to miss the tabs to find treatment/diagnosis trees and drug guides of most of the drugs available in england.

Wikipedia page on schizophrenia:


In depth and up-to-date reference of most areas of schizophrenia.

Image courtesy of Wikimedia Commons under creative commons license: https://en.wikipedia.org/wiki/Image:Schizophrenia_PET_scan.jpg



For every 5 people who develop schizophrenia:

  • 1 in 5 will get better within five years of their first episode of schizophrenia.
  • 3 in 5 will get better, but will still have some symptoms.
  • 1 in 5 will continue to have troublesome symptoms.