69. Thought disorder and language in schizotypal personality disorder

Abstract

Preliminary data from our laboratory have suggested that the amount and quality of thought disorder (as measured by the Thought Disorder Index [TDI]) in Schizotypal Personality Disorder (SPD) is similar to that found in schizophrenic (SZ) subjects and their relatives. The TDI score is based on a verbatim sample of language. Because verbal skills can be reduced in SPD, it is unclear how TDI scores might be related to general deficits in language skills. The purpose of the current study was to examine the relationship between TDI scores and performance on verbal neuropsychological measures in SPD. In addition to the TDI, 20 right-handed male SPD subjects were administered a battery of language-based neuropsychological tests, including vocabulary, reading, spelling, naming, repetition, comprehension, verbal fluency, and verbal learning. The group was divided into low (n = 10) and high (n = 10) TDI scorers; performance on verbal neuropsychological tests and demographic variables in these groups were compared. The groups did not differ in general verbal ability or language skills, nor were differences apparent in demographic variables, depression, or positive/negative symptom profile. In contrast, SPDs with higher TDI scores learned fewer words and used fewer semantic clusters on the California Verbal Learning Test (CVLT, p < .05), a measure which may be selectively impaired in SPD. The results suggest that thought disorder may be related to impaired verbal learning in SPD, and support hypotheses of disinhibition of the semantic language network in schizophrenia spectrum disorders.