Positron-emission tomographic (PET) studies and genetic research of
stuttering have recently revealed underlying cerebral neurobiologic contributing factors in this disorder. We aimed to assess whether
cognitive impairment and other neuropsychiatric dimensions could be detected through computerized content analysis of short samples of speech from stutterers, and whether administration of
risperidone in a double-blind placebo-controlled study could decrease the severity of
stuttering, as well as any of the neuropsychiatric features of these stutterers. A group of 21 stutterers with the developmental form of
stuttering, an onset before age of 6 years, aged 20 to 74 years, and who were otherwise free of major medical or psychiatric problems, initially gave a 5-minute tape-recorded speech sample in response to purposely ambiguous instructions to talk about any interesting or dramatic life experiences. Then, half of these subjects (n = 10) were randomly selected to receive 6 weeks of
risperidone treatment up to 2.0 mg/d and the other half (n = 11) were administered a placebo. Both groups of subjects gave a second verbal sample after 6 weeks of treatment. Significantly elevated
cognitive impairment and social alienation-personal disorganization scores, derived from the computerized content of the initial 5-minute speech samples, were found. After 6 weeks, the
risperidone group improved significantly on a measure of severity of
stuttering but did not improve on the percentage of time spent
stuttering. The placebo group did not improve on either measure of
stuttering. The psychopathological processes of subjects who received
risperidone treatment, including those with elevated
cognitive impairment and social alienation-personal disorganization, did not change significantly. However, stutterers who had lower scores on verbal content analysis-derived shame anxiety, guilt anxiety, or hostility inward measures improved significantly more with
risperidone than stutterers with higher scores on these measures. The findings of elevated
cognitive impairment and social alienation-personal disorganization scores of adult stutterers with the early developmental form of
stuttering are consistent with the neurobiologic abnormalities found in PET-scan and genetic research involving stutterers.
Risperidone (< or =2.0 mg/d) can reduce the severity of
stuttering while not significantly affecting the magnitude of neuropsychiatric dimensions such as
cognitive impairment or social alienation-personal disorganization. The less the inward shame, guilt, or hostility of the stutterers, the better the beneficial effect of
risperidone on the severity of
stuttering.