Symptoms:

• Active, but in an aimless and not constructive way
• Bizarre and inappropriate emotional responses
• False, fixed beliefs (delusions)
• Inability to feel pleasure
• Inappropriate grinning and grimacing
• Lack of emotion and motivation
• Seeing or hearing things that aren't there (hallucinations)
• Silly behavior

Some of these symptoms are also seen in other types of schizophrenia. The main difference is erratic behavior, with speech that is not grammatical or is random-ordered.

Signs and tests:

Diagnosis involves:

• Laboratory tests
• Physical examination
• Psychiatric evaluation

These tests can help rule out other causes of the symptoms.