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Negative symptoms

What are negative symptoms?

The ‘negative symptoms’ of schizophrenia refer to an absence of normal functions. This includes a scarcity of facial expressions of emotion, reduced frequency and range of gestures and voice modulation, restricted eye contact, poverty of speech, reduced social interaction, reduced motivation, poor hygiene, and reduced experience of pleasure often manifesting as scarcity of recreation, inability to experience closeness, and reduced interest in any sexual activity. Deficit schizophrenia is a subtype of schizophrenia with persisting negative symptoms that is described by specifically defined assessments used primarily for research.

What is the evidence regarding negative symptoms?

Moderate to low quality evidence indicates negative symptoms occur in 50-90% of patients during a first episode of psychosis, which decreases to 35-70% with treatment, and 20-40% of patients have negative symptoms that persist indefinitely. High quality evidence shows a small effect of more severe negative symptoms in patients with a family history of psychosis compared to patients without a family history of psychosis, and significant concordance of psychomotor poverty symptoms between siblings with schizophrenia. Moderate to low quality evidence suggests negative symptoms may be associated with structural and functional changes in the temporal and frontal lobes, and functional changes in the cerebellum and thalamus.

Moderate to low quality evidence suggests that speech deficits are apparent in people with schizophrenia, with large effects of reduced variability of pause time, reduced percentage of time talking, and reduced pause length. There are medium-sized effects of reduced number of words spoken, and reduced variability of pitch. There are small effects of reduced utterance length, reduced time to initiate speech, reduced number of pauses, and increased variability in volume and intensity.

High quality evidence shows that deficit schizophrenia is associated with greater severity of negative and, to a lesser extent, greater severity of disorganisation symptoms, less severe mood symptoms, and no association with positive symptoms. Deficit schizophrenia is also significantly more likely to occur in males than in females.

Also see the Diagnosis, outcome assessment tools topic and the Treatments for negative symptoms and antidepressants topics.

 

April 2016

Page last updated: 1:52  7 September 2017

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