Sluggish Cognitive Tempo (SCT) describes individuals who are dreamy, spacey, slow moving, hyper active, have difficulty initiating tasks, and often seem under-motivated and under-aroused. Barkley identified nine cardinal symptoms of SCT: 1) prone to daydreaming instead of concentrating; 2) trouble staying alert/awake in boring situations; 3) being easily confused; 4) being easily bored; 5) feeling spacey/in a fog; 6) frequently feeling lethargic; 7) being under-active/having less energy than others; 8) being slow moving; 9) not processing information quickly/accurately. Individuals were identified as SCT if they had at least 5 of 9 symptoms rated often or very often on the 9-item SCT subscale from the Barkley Adult ADHD Rating Scale-IV: Self-Report (BAARS-IV; hereafter called the Barkley SCT Scale).

This is a 2 Site (NYU and Mount Sinai) Study of LDX in 50 adults with Attention Deficit Disorder (ADHD) and Sluggish Cognitive Tempo (SCT). The study will be a double-blind, 10-week, cross-over treatment trial of LDX (4 weeks; 30 - 70 mg/day) vs. placebo (4 weeks) with an intervening single- blind placebo washout period (2 weeks). During the LDX treatment period, LDX treatment will be initiated at a dose of 30mg/day at Visit 0 and can be titrated up (in the judgment of the investigator) in increments of 20mg, based upon clinical response and tolerability, to 50mg/day at Visit 1 and 70mg/day at Visit 2. Subjects receiving daily doses of 50mg or 70mg of LDX will be allowed to down titrate one dosage step of 20mg during Visits 2-4 if (in the judgment of the investigator) they are having issues in tolerability. The highest effective dose of LDX will then be maintained until Visit 4. Patients will be seen weekly throughout the trial except during placebo washout.