55 下列何種症狀屬於精神分裂症的負性症狀（negative symptoms）？

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Positive and negative symptoms

Schizophrenia is often described in terms of positive and negative (or deficit) symptoms.^[16] The term positive symptomsrefers to symptoms that most individuals do not normally experience but are present in schizophrenia. They include

delusions,

auditory hallucinations, and

thought disorder, and are typically regarded as manifestations of psychosis.

Negative symptoms are things that are not present in schizophrenic persons but are normally found in healthy persons, that is, symptoms that reflect the loss or absence of normal traits or abilities. Common negative symptoms include

flat orblunted affect and emotion,

poverty of speech (alogia),

inability to experience pleasure (anhedonia),

lack of desire to form relationships (asociality), and

lack of motivation (avolition).

Research suggests that negative symptoms contribute more to poor quality of life, functional disability, and the burden on others than do positive symptoms.^[17]