ABSTRACT
Most of the negative symptoms of schizophrenia are behavioural abnormalities and thus should more properly be called signs. Stereotyped behaviour is a prominent feature of schizophrenia and had been associated with madness long before the syndrome of schizophrenia was first described. Incoherence of speech and incongruity of affect are traditionally classified as positive symptoms because they are abnormal by their presence. If negative signs reflect a problem with spontaneous, self-initiated action, then signs such as poverty of will (lack of volition), poverty of speech, and poverty of thought start to become explicable. This chapter also considers evidence from lesion studies in animals and studies of neurological patients to see if the behavioural abnormalities observed in schizophrenia can be related to any particular brain locations. Parkinson's disease relates to schizophrenia, not only because similar negative features can be observed in both disorders, but also because the neurotransmitter, dopamine, is implicated in both.
