Negative Symptoms: Relationship to Other Schizophrenic Symptom Classes

If negative symptoms represent a distinct class of schizophrenic symptoms, they should, to paraphrase Bleuler (1911), be more closely related to each other than they are to other schizophrenic symptoms. The first part of this statement, that negative symptoms are intrinsically related to each other, has received considerable experimental support (Andreasen, this volume; Mortimer et al, this volume). The second, that negative symptoms are unrelated to other schizophrenic symptoms, has been somewhat more unevenly investigated.

Pathology, Phenomenology and the Dopamine Hypothesis of Schizophrenia

The dopamine hypothesis of schizophrenia implies that positive schizophrenic symptoms should be understandable by reference to brain structures receiving a dopamine innervation, or in terms of the functional role of dopamine itself. The basal ganglia, ventral striatum, septo-hippocampal system, and prefrontal cortex, sites of mesotelencephalic dopamine innervation, are examined and it is argued that their dysfunction could form the basis of particular schizophrenic symptom classes. The postulated involvement of dopamine in reinforcement processes might further assist such interpretations. This type of analysis can be extended to other categories of schizophrenic psychopathology.