Wednesday, May 4, 2016

Schizophrenia, Anhedonia, and Affectivity:

the relationship between anhedonia, affectivity, and poor social functioning exhibited by schizophrenic patients

Anhedonia is defined as the lack of vitality commonly felt in patients suffering with unremitting depression. Anhedonia has been associated with low positive affect which is another trait that researchers have found to be associated with depression. In the study “Low Positive Affect is Associated with Reduced Prefrontal Cortical Activity in Remitted Depression,” Rebecca Silton explores the relationship between low positive affect and prefrontal brain activity to examine differences in subjects with depression and normal control subjects. In the study “Anhedonia,Positive and Negative Affect, and Social Functioning in Schizophrenia,” Jack Blanchard, Kim Mueser, and Alan Bellack proposed that anhedonia and low positive affect are also related to emotional functioning in schizophrenia, such as the underlying social isolation evident in patients with schizophrenia. Instead of studying the association between anhedonia and psychosis proneness which has already been done or focusing on the relationship between affectivity and prefrontal alpha like Silton, Blanchard, Mueser, and Bellack focused on anhedonia’s relationship to specific features of schizophrenia in affected patients.
They chose to focus on trait affect correlates of anhedonia because they are more reliable, less-restrictive when assessing trait affectivity, and will allow the researchers to better understand how anhedonia is related to positive and negative affect. The trait measures of effect were completed using the Multidimensional Personality Questionnaire, a self-report survey that has been used in several other studies in psychopathology. The first part of the study tested whether anhedonia, positive affect, and negative affect reflected individual differences in patients with schizophrenia. Then, the relationship between anhedonia and trait dimensions of positive and negative affect was evaluated. The final goal of the study was to elucidate the relationship, if any, between anhedonia and social functioning schizophrenia since social dysfunction is a key feature of the disorder. It was hypothesized that anhedonia underlies social withdrawal and impairment in individuals with schizophrenia. Poor social functioning characteristics included in the study were fewer friends, less social activities, and less involvement in romance.
To examine the relationship between anhedonia and poor social functioning, the researchers assessed schizophrenia outpatients and normal controls twice in 90 days to test the following: the stability of trait indices of anhedonia and affectivity, whether schizophrenia subjects reported greater anhedonia, whether anhedonia is associated with less trait positive affect and greater trait negative affect, and if the poor social functioning exhibited by schizophrenia subjects (if this is the case) is correlated with greater anhedonia and less positive affect. After the final correlational analyses were completed in order to evaluate relationships between anhedonia, affectivity, anxiety, and social functioning within the schizophrenia subjects, it was concluded that schizophrenic subjects reported greater physical and emotional anhedonia and less trait positive affect than normal control subjects did, but they also reported greater trait negative affect and greater social anxiety than control subjects did. This result, along with other calculations, allowed the researchers to conclude that anhedonia can be used as a marker for low positive affect and high negative affect. Also, the poor social functioning exhibited by schizophrenic subjects was significantly correlated with greater levels of anhedonia. The evident correlation between positive affect and social functioning was less understood; increased positive affect may increase tendencies to engage in social activity or participation in social activities may result in increased positive affect. However, lower positive affect was evident in schizophrenic subjects with poorer social functioning.
In synopsis, schizophrenic patients in this study were characterized by high physical and emotional anhedonia, low positive affect, and high negative affect. The relationship between affectivity and anhedonia can be a key insight into the mechanisms behind disorders like schizophrenia and depression. A better understanding of these relationships has significant implications for the development of new and integrative positive-emotion-interventions in treatment for these disorders.

References:

Rebecca Silton, Kelly Polnaszek, Daniel Dickson, Wendy Heller, Gregory Miller,  "Low Positive Affect is Associated with Reduced Prefrontal Cortical Activity in Remitted Depression"

Jack J. Blanchard, Kim T. Mueser, Alan S. Bellack, "Anhedonia, Positive and Negative Affect, and Social Functioning in Schizophrenia" 

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