This study compared the subjective, physiological, and psychomotor effects of atomoxetine
and methylphenidate with placebo in healthy volunteers. Sixteen non-dependent light
drug users participated in six experimental sessions, receiving placebo, atomoxetine
(20, 45 and 90 mg) and methylphenidate (20 and 40 mg) using a double-blind, Latin
square design. Subjective drug effects were assessed using Visual Analog Scales (VAS),
the Addiction Research Center Inventory (ARCI) and Adjective Rating Scales (ARS).
Psychomotor performance was evaluated using the Digit Symbol Substitution Test (DSST).
Physiological measures were also collected throughout the sessions. Assessments were
conducted before drug administration and 30, 60, 90, 120, 150, 180 and 240 min following
dosing. Forty milligrams methylphenidate produced significant increases on the stimulant
portions of the VAS and ARS and the benzedrine, amphetamine, morphine-benzedrine and
lysergic acid diethylamine (LSD) subscales of the ARCI relative to placebo. Ninety
mg atomoxetine was reported to be unpleasurable relative to placebo as indicated by
significant increases on the 'bad' and 'sick' portions of the VAS, and on the LSD
subscale of the ARCI. Compared with placebo, both methylphenidate doses significantly
increased systolic blood pressure (BP) and heart rate (HR). For atomoxetine, 90 mg
increased diastolic BP, 45 and 90 mg increased systolic BP, and all three doses increased
HR relative to placebo. Neither compound produced significant differences from placebo
on DSST performance. These results suggest that atomoxetine does not induce subjective
effects similar to methylphenidate and suggest that it is unlikely that atomoxetine
will have abuse liability.