PSYCHIATRIC-SYMPTOMS DO NOT CORRELATE WITH COGNITIVE DECLINE, MOTOR SYMPTOMS, OR CAG REPEAT LENGTH IN HUNTINGTONS-DISEASE

Objective: To investigate the hypothesis that psychiatric disturbances in Huntington's disease are related to degree of cognitive or motor c ompromise and to determine correlations between CAG repeat length with in the gene for Huntington's disease and disease severity. Design: Con secutive series of patients with Huntington's disease. Setting: Neurol ogical specialty hospital. Patients: Seventeen men and 12 women from 2 4 families. Main Outcome Measures: The Hamilton Psychiatric and Anxiet y Rating Scales and Brief Psychiatric Rating Scale were used to assess psychiatric disturbances; Folstein's Quantified Neurological Examinat ion to evaluate motor status; and the Mini-Mental State Examination, R aven Progressive Matrices), Phonemic Verbal Fluency Test, Short Tale T est, Visual Search Test, and Benton's Visual Orientation Line Test to evaluate cognitive function. The length of the CAG repeat sequence in the Huntington's gene was determined by quantitative polymerase chain reaction. Results: Cognitive test scores correlated significantly with each other; of these, results of the Visual Search and Short Tale tes ts correlated significantly with the Folstein's Quantified Neurologica l Examination score (P=.05 and P=.03, respectively). Results of the Fo lstein's Quantified Neurological Examination also correlated with the illness duration and the length of the CAG repeat. Although psychiatri c scores correlated significantly among themselves (P<.01), neither co gnitive compromise, motor deterioration, nor CAG length were related t o the extent of psychiatric compromise. Patients who were depressed wh en they were examined tended to have a history of psychiatric disorder s. Conclusions: The lack of correlation between disease severity and p sychiatric disturbances indicates that psychiatric disorders progress nonlinearly, possibly because of differential degeneration of the stri atal-cortical circuits; the possibility that psychiatric disorders are prevalent in certain families with a member who has Huntington's dise ase is being further investigated. The lack of correlation between CAG length and cognitive and psychiatric variables needs further investig ation.