Anhedonia in schizophrenia

Objective: Anhedonia, a term first used by Ribot in 1896, is a decreased capacity to experience pleasure. It describes the lack of interest and the withdrawal from all usual and pleasant activities. There are two types of hedonic deficit: physical anhedonia and social anhedonia. Physical anhedonia represents the inability to feel physical pleasures (such as eating, touching and sex), while social anhedonia describes the incapacity to experience interpersonal pleasure (such as being and talking to others). In schizophrenia, anhedonia had differently been considered as a personological trait giving rise to the development of psychosis or as a basic symptom underlying the pathological process. Aim of this study was to examine the psychopathological characteristics of anhedonia in schizophrenic patients and to investigate the clinical relations with negative, positive, disorganized and depressive symptoms. Methods: Sixty schizophrenic subjects (25 inpatients and 35 outpatients) attending the Guastalla's Psychiatric Operative Unit, were assessed using the Scales for Physical and Social Anhedonia (PAS and SAS), the Scales for the Assessment of Positive and Negative Symptoms (SAPS and SANS) and the Calgary Depression Scale for Schizophrenics (CDS). Chapman's Scales (PAS and SAS) are two "true-false" self-report instruments measuring the personological (enduring trait-feature) diminished ability to experience sensory and interpersonal pleasures (such as eating, touching, being with and talking to others, sex, smell and sound). Regarding the (PAS and SAS) cut-offs above which a subject can be classified as "anhedonic", we decided to use those proposed in the French version of Chapman's scales (respectively, ≥ 12 for social anhedonia and ≥ 18 for physical anhedonia) on account of the greater specificity and sensitivity compared to Chapman's original limits. Differently, the SANS "Anhedonia/Asociality" sub-scale must be considered as a symptomatological complex (state-like feature) indicating the individual hedonic deficit in pleasant activities. The statistical analysis of the data was performed in two steps using SPSS 10.0. At first, the schizophrenic sample was dichotomized into "anhedonic" and "normal hedonic" subgroups ("double [PAS/SAS] cut-off"), which were compared on the psychopathological scales using the Mann-Whitney Z test; subsequently, in the total schizophrenic sample, Spearman's correlations and a linear regression analysis were calculated to examine the possible association of psychopathological parameters with Chapman's anhedonia ratings (PAS and SAS total scores) Results: Anhedonia reached highly significant levels only in 45% of the schizophrenic sample (n = 27). This "anhedonic" subgroup was distinguished by high scores in disorganization and negative dimensions [no statistical differences in terms of depression and positive symptoms (hallucinations and delusions) were detected between "anhedonic" and "normal hedonic" groups]. Positive correlations between anhedonia [PAS tot. and SAS tot. (as independent variables)], disorganized and negative symptoms [SANS tot. and "disorganization" SAPS subscales (as dependent variables)] have also been described. Conclusions: In this schizophrenic sample, anhedonia appears to be a predictive factor (psychopathological forerunner) for the development of negative and disorganized forms of schizophrenia ("deficit" or "hebephrenic" subtypes).