Characterization of the longitudinal course of improvement in generalized anxiety disorder during long-term treatment with venlafaxine XR.
OBJECTIVE
To characterize the response to the serotonin and norepinephrine reuptake inhibitor, venlafaxine extended release (XR), during the long-term treatment of generalized anxiety disorder.


METHODS
Data from two double-blind, placebo-controlled, 6-month trials of venlafaxine XR for the treatment of generalised anxiety disorder were pooled. Criteria for response (> or = 50% improvement from baseline HAM-A score) and remission (HAM-A score < or = 7) and their temporal profile were used to characterize patient improvement over 6 months of treatment with venlafaxine XR and placebo.


RESULTS
Venlafaxine XR was associated with significantly (P<0.001) higher response and remission rates (66 and 43%, respectively) compared with placebo (39 and 19%), regardless of the level of baseline anxiety. In the venlafaxine XR group, 61% of the patients who had responded but not remitted by week 8 showed remission by the end of 6 months. In comparison, only 39% of placebo responders who did not qualify for remission at the end of the first 8 weeks of therapy remitted by the end of the 6 months (P=0.007). Relapse occurred in 6% of venlafaxine XR-treated patients and 15% of placebo-treated patients (P<0.01).


CONCLUSIONS
This analysis provides further insight into the outcome of long-term treatment of generalised anxiety disorder with venlafaxine XR and shows for the first time that long-term treatment might be necessary to achieve and maintain remission of symptoms.
Imperial College School of Medicine, PO Box 8751, London, UK. sam@montgomery.demon.co.uk
Stuart A
SA
Montgomery
David V
DV
Sheehan
Paolo
P
Meoni
Vincent
V
Haudiquet
David
D
Hackett
D000328:Adult; D001008:Anxiety Disorders / Q000175:diagnosis / Q000188:drug therapy* / Q000523:psychology; D003511:Cyclohexanols / Q000009:adverse effects / Q000627:therapeutic use*; D003692:Delayed-Action Preparations; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D008134:Long-Term Care; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D015337:Multicenter Studies as Topic; D016032:Randomized Controlled Trials as Topic; D017367:Selective Serotonin Reuptake Inhibitors / Q000009:adverse effects / Q000627:therapeutic use*; D016896:Treatment Outcome; D000069470:Venlafaxine Hydrochloride
D003511:Cyclohexanols; D003692:Delayed-Action Preparations; D017367:Selective Serotonin Reuptake Inhibitors; D000069470:Venlafaxine Hydrochloride