| Popis: |
The current chapter reviews the history and progression of negative symptoms of schizophrenia, with a particular focus on avolition, highlighting major issues in the conceptualization, structure, assessment, and etiology of negative symptoms. Avolition has been a core pathology in schizophrenia constructs beginning with Kraepelin’s “weakening of the wellsprings of volition” and concepts of anhedonia and schizotaxia developed by Rado and Meehl and more recently in the positive and negative symptom distinctions proposed in 1974. The primary/secondary distinction of negative symptoms, usually ignored, is critical in ascertaining a core pathology in schizophrenia and defining a disease entity within the schizophrenia syndrome. Negative symptoms can be used as a dimensional construct and have been viewed as an unmet therapeutic need in schizophrenia. Assessment methods have been refined with two current instruments addressing two factors related to expressivity and motivation. Negative symptoms as a psychopathology dimension and as a category [taxon] have been validated. The role of anhedonia in avolition has been challenged by in-the-moment assessments, suggesting intact capacity for pleasure but difficulty using mental representations of affective value to guide decision-making and goal-directed behavior. Part II by Strauss et al. addresses laboratory-based investigations and provides a novel theoretical framework for understanding avolition, as well as future directions for negative symptom research and clinical care. |
