Schizophrenia is a psychiatric diagnosis denoting a persistent, often chronic,
mental illness variously affecting behaviour, thinking, and emotion. The term
schizophrenia comes from the Greek words (schizo, split or divide) and (phrenos,
mind) and is best translated as "shattered mind".
Schizophrenia is most commonly characterised by both 'positive symptoms' (those
additional to normal experience and behaviour) and negative symptoms (the lack
or decline in normal experience or behaviour). Positive symptoms are grouped
under the umbrella term psychosis and typically include delusions, hallucinations,
and thought disorder. Negative symptoms may include inappropriate or lack of
emotion, poverty of speech, and lack of motivation. Additionally, neurocognitive
deficits may be present. These take the form of reduction or impairment in basic
psychological functions such as memory, attention, problem solving, and social
cognition. The onset is typically in late adolescence and early adulthood, with
males tending to show symptoms earlier than females.
Psychiatrist Emil Kraepelin was first to make the distinction between what
he called dementia praecox and other forms of madness. This classification was
later renamed 'schizophrenia' by psychiatrist Eugene Bleuler as it became clear
Kraepelin's name was not an adequate description of the condition.
The diagnostic approach to schizophrenia has been opposed, most notably by
the anti-psychiatry movement, who argue that classifying specific thoughts and
behaviours as illness allows social control of people that society finds undesirable
but who have committed no crime.
More recently, it has been argued that schizophrenia is just one end of a spectrum
of experience and behaviour, and everybody in society may have some such experiences
in their life. This is known as the 'continuum model of psychosis' or the 'dimensional
approach' and is most notably argued for by psychologist Richard Bentall and
psychiatrist Jim van Os.
Although no definite causes of schizophrenia have been identified, most researchers
and clinicians currently believe that schizophrenia is primarily a disorder
of the brain. It is thought that schizophrenia may result from a mixture of
genetic disposition (genetic studies using various techniques have shown relatives
of people with schizophrenia are more likely to show signs of schizophrenia
themselves) and environmental stress (research suggests that stressful life
events may precede a schizophrenic episode).
It is also thought that processes in early neurodevelopment are important,
particularly those that occur during pregnancy. In adult life, particular importance
has been placed upon the function (or malfunction) of dopamine in the mesolimbic
pathway in the brain. This theory, known as the dopamine hypothesis of schizophrenia
largely resulted from the accidental finding that a drug group which blocks
dopamine function, known as the phenothiazines, reduced psychotic symptoms.
These drugs have now been developed further and antipsychotic medication is
commonly used as a first line treatment. However, this theory is now thought
to be overly simplistic as a complete explanation.
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