Figure 2.

Percentage decrease of whole blood serotonin (5-HT) over a 6-week period. Medication regimens were titrated weekly, but they could remain on the same dose level for an additional 1 or 2 weeks, but all patients reached level 4 for at least for 1 week after 6 weeks. The baseline levels of 5-HT in nmol/L were 788 ± 107, 897 ± 253, and 719 ± 129 in the atomoxetine, paroxetine, and venlafaxine groups, respectively. Atomoxetine levels were: 25, 43, 65, and 80 mg/d; venlafaxine levels were 75, 150, 225, and 375 mg/d; paroxetine levels were: 20, 30, 40, and 50 mg/d. *P < .05 indicates statistical differences within each treatment group when compared with their respective baseline. There were no statistically significant differences between the venlafaxine and paroxetine groups, but atomoxetine produced significantly lesser decreases of 5-HT levels than the other 2 medications.