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1School of Psychiatry, University of New South Wales, Psychiatry Unit, Prince of Wales Hospital, Randwick, Australia. g.parker@unsw.edu.au
The Australian and New Zealand Journal of Psychiatry
|February 24, 2001
Summary
Antidepressant efficacy studies suggest a delayed onset of action. This study found early, sustained improvement predicts treatment response, challenging the delayed onset hypothesis for antidepressants.
Area of Science:
- Psychiatry
- Clinical Psychology
- Pharmacology
Background:
- Antidepressant efficacy studies often face interpretation challenges.
- The proposition of a delayed onset of action for antidepressants is debated.
Purpose of the Study:
- To investigate the onset of antidepressant action using refined measurement and analytic strategies.
- To address confounding factors in previous antidepressant efficacy studies.
Main Methods:
- A longitudinal study design was employed with a subset of patients.
- Depression and anxiety measures were collected every 3 days over 4 weeks.
- Trajectories of responders and non-responders were compared.
Main Results:
- Both responders and non-responders showed similar initial improvement in the first 3 days.
- A divergence in improvement trends occurred after day 3.
- Early improvement between days 3-6 strongly predicted responder status.
Conclusions:
- Findings suggest antidepressants may not have an extensive delayed onset of action.
- Early and sustained improvement is a more reliable marker of treatment response than immediate improvement.
- Further research is needed due to the small sample size, but the design offers interpretive advantages.
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