Stability of estimated IQ across mood state in patients with bipolar disorder.

Objectives: The goal of this study was to assess the impact of mania symptoms on the stability of the American version of the National Adult Reading Test (ANART), a measure that provides a putative estimate of premorbid intellectual functioning. Methods: The ANART was administered to a sample of 10 inpatients with bipolar disorder who were experiencing an acute episode of mania. During a subsequent follow-up visit during which these individuals exhibited at most minimal mood symptoms, the ANART was re-administered. Results: ANART estimated intelligence quotient (IQ) scores during mania and affective stability were assessed in the 10 patients using a paired sample t-test. Within-subject performance across the two mood states did not significantly differ [t(9) = -1.24, p = 0.25]. Additionally, the greatest individual difference across mood states was only 3.68 points, and the average estimated IQ difference across mood states was 1.66. Conclusions: While the results are preliminary and based on a small sample, the highly consistent scores achieved across mood states in this study suggest that the ANART is a reliable indicator of premorbid IQ.