What would be a negative symptom of schizophrenia?

Schizophrenia is a mental illness where patients start to hear voices in their heads. They can develop split personalities and often believe that someone is telling them to do something. Such patients often repeat senseless words and phrases. Sometimes they can experience euphoria when such an episode is about to start. The biggest problem is that they do not trust anyone.

They often think that doctors are bad and about to get you. Often they also think that they are powerful and can do anything, which leads to severe consequences. However, they do not exhibit flattened emotional expression. This last feature is associated with Parkinsonism.