Deficits in Verbal Working Memory among College Students with Attention-Deficit/Hyperactivity Disorder Traits: An Event-related Potential Study

OBJECTIVE: This study investigated verbal working memory in college students with traits of attention-deficit/hyperactivity disorder (ADHD) using event-related potentials and the 2-back task. METHODS: Based on scores on the Adult ADHD Self-Report Scale and Conners’ Adult ADHD Rating Scale, participants were assigned to the normal control (n=28) or ADHD-trait (n=29) group. The 2-back task, which was administered to evaluate working memory, consists of a congruent condition, under which the current stimulus is the same as the one presented two trials earlier, and an incongruent condition, under which the current stimulus is not the same as the one presented two trials earlier. The numbers 1, 2, 3, and 4 were used as stimuli. RESULTS: On the 2-back task, the ADHD-trait group committed significantly more errors in response to congruent stimuli and showed a smaller P300 amplitude than did the control group. CONCLUSION: These results indicate that college students with ADHD traits have deficits in verbal working memory, possibly due to difficulties in memory updating or attentional allocation.