Negative symptoms in Huntington's disease

Apathy is the commonest psychiatric manifestation in Huntington's disease (HD). We investigated negative psychiatric symptoms-as determined by the Scale for the Assessment of Negative Psychiatric Symptoms (SANS)-in early and intermediate HD patients, hypothesizing that such symptoms would be prominent and constitute a more comprehensive and clinically relevant assessment than apathy alone. We also assessed relations between negative symptoms and disease stage, mood, motor, and cognitive disturbances.

Thirty-five stage 1 and twenty-nine stage 2 consecutive adult HD outpatients were administered SANS; the Scale for the Assessment of Positive Psychiatric Symptoms (SAPS); the motor section of the Unified Huntington's Disease Rating Scale (UHDRS); Total Functional Capacity (TFC); and instruments to assess cognition, anxiety, and depression.

The groups had similar age, education, and CAG length. Scores on the Hamilton depression and anxiety scales, and SAPS were similar. Negative symptoms were pervasive in the entire series. Illness duration, UHDRS, TFC, cognition, and SANS scores were significantly worse in stage 2. Mini Mental State Examination (MMSE) and SAPS scores were significantly (multiple regression) associated with SANS score, while Hamilton depression and UHDRS scores were not. SANS score was also associated with stage after removing the cognition-related domains of alogia and attention.

Negative symptoms are pervasive in HD but more severe in stage 2. The associations of SANS with MMSE and SAPS suggest impaired cognition and thinking as important in generating negative symptoms. SANS appears useful for revealing a wide range of negative symptoms in HD.