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 syndrome 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 high quality evidence shows deficit syndrome is apparent in around one-third of people with schizophrenia. It is associated with greater severity of negative and disorganised symptoms, lesser severity of mood symptoms, and no association with positive symptoms. Deficit syndrome is more likely to occur in males than females.

Moderate to low quality evidence indicates negative symptoms occur in 50-90% of people with first episode psychosis. This estimate decreases to 35-70% with treatment, and 20-40% of patients have persisting negative symptoms.

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. There is also significant concordance of psychomotor poverty in siblings with schizophrenia. Negative symptoms are associated with structural changes in temporal and frontal lobes, and functional changes in frontal and temporal lobes, and the cerebellum and thalamus.

Moderate quality evidence finds speech deficits in people with schizophrenia. There are large effects of less variability in pause time, less time talking, and shorter pause length. Medium-sized effects are found for fewer number of words spoken and less variability of pitch. Small effects are found for shorter utterance length, decreased time to initiate speech, fewer number of pauses, and increased variability in volume and intensity.

Moderate to low quality evidence finds low mood, suicidal ideation, and pessimism are most commonly associated with depression, alogia and blunted affect are most commonly associated with negative symptoms, and anhedonia, lack of energy, and avolition are associated with both.

July 2019

Last updated at: 3:09 am, 16th July 2019
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