What do we really know about blunted vocal affect and alogia? A meta-analysis of objective assessments.
OBJECTIVE Although negative symptoms are prominent in older patients with schizophrenia, it is unknown whether this pattern is prevalent in healthy participants. The objective of this study was to evaluate whether negative symptoms are present in healthy populations and to determine whether they are linked to illness-related processes or normal aging. METHODS A systemic review of 26 studies that have administered negative symptom assessments to healthy participants was conducted. In addition, 213 (age > 40 years old) healthy participants completed PANSS and SANS ratings at both baseline and 1-year follow-up. One-hundred participants also completed ratings after 3 years. RESULTS Across all reviewed studies, negative symptoms were absent in the majority of participants. Comparable results were found in the current study's large longitudinal evaluation with middle-aged to older adults. CONCLUSIONS Taken together, the data suggest that healthy volunteers do not suffer from prominent negative symptoms. This finding is consistent with the hypothesis that the greater prevalence and severity of negative symptoms in older patients is not related to normal aging but to illness-related processes.