Do venlafaxine XR and paroxetine equally influence negative and positive affect?
BACKGROUND
We assessed the therapeutic effects of venlafaxine XR and paroxetine on mood and anxiety symptoms derived from the tripartite model of mood. We hypothesized that the two antidepressants would have largely similar effects on symptoms of negative affect because both agents influence serotonergic systems. However, based on evidence indicating linkages between catecholaminergic activity and the emotional dimension of positive affect, we hypothesized that the catecholaminergic effects of venlafaxine XR would yield particularly pronounced effects on symptoms of positive affect.


METHODS
Twenty depressed outpatients were randomly assigned to treatment with either venlafaxine XR (225 mg/day) or paroxetine (30 mg/day) during a 12-week treatment trial. Weekly mood ratings were collected using the Mood and Anxiety Symptom Questionnaire [Watson, D., Clark, L.A., Weber, K., Assenheimer, J.S., Strauss, M.E., McCormick, R.A., 1995. Testing a tripartite model: II. Exploring the symptom structure of anxiety and depression in student, adult, and patient samples. J. Abnorm. Psychol. 104 (1), 15-25] [Watson, D., Weber, K., Assenheimer, J.S., Clark, L.A., Strauss, M.E., McCormick, R.A., 1995. Testing a tripartite model: I. Evaluating the convergent and discriminant validity of anxiety and depression symptom scales. J. Abnorm. Psychol. 104 (1), 3-14].


RESULTS
Consistent with predictions, analyses revealed that there were no significant differences between venlafaxine XR and paroxetine on measures of negative affect. However, contrary to predictions, the two medications produced similar changes on measures of positive affect.


CONCLUSIONS
Replication and extension using a larger sample size are mandated.


CONCLUSIONS
These preliminary results suggest that two antidepressants that appear to have dissimilar mechanisms of action may nevertheless have similar effects on the positive and negative affective components of depression. Alternatively, paroxetine may have a clinically relevant noradrenergic effect at the dose tested.
Dichter
Gabriel S
GS
Department of Psychology, College of Arts and Sciences, Wilson Hall, Vanderbilt University, Nashville TN 37203, USA.
Tomarken
Andrew J
AJ
Freid
Cathryn M
CM
Addington
Stephanie
S
Shelton
Richard C
RC
D000328:Adult; D000339:Affect / Q000187:drug effects*; D018687:Antidepressive Agents, Second-Generation / Q000627:therapeutic use*; D001008:Anxiety Disorders / Q000175:diagnosis / Q000188:drug therapy* / Q000523:psychology; D003511:Cyclohexanols / Q000627:therapeutic use*; D003692:Delayed-Action Preparations; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000188:drug therapy* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017374:Paroxetine / Q000627:therapeutic use*; D010552:Personality Assessment; D012044:Regression Analysis; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*; D016896:Treatment Outcome; D000069470:Venlafaxine Hydrochloride
D018687:Antidepressive Agents, Second-Generation; D003511:Cyclohexanols; D003692:Delayed-Action Preparations; D017374:Paroxetine; D017367:Selective Serotonin Reuptake Inhibitors; D000069470:Venlafaxine Hydrochloride