What are the clinical implications of new onset or worsening anxiety during the first two weeks of SSRI treatment for depression?

Objective: To evaluate the prevalence of new onset or worsening of anxiety symptoms, as well as their clinical implications, during the first 2 weeks of Selective Serotonin Reuptake Inhibitor (SSRI) pharmacotherapy for depression. Method: Adult outpatients with nonpsychotic major depressive disorder were enrolled in an 8-week acute phase SSRI treatment trial at 15 clinical sites across the United States. Worsening anxiety was defined as a greater than 2-point increase on the Beck Anxiety Inventory (BAI) between baseline and Week 2. New onset of anxiety symptoms was ascribed when the BAI baseline rating was 0 and the Week 2 value was greater or equal to 2 points on the BAI. Results: Overall, after 2 weeks of treatment, 48.8% (98 of 201 participants) reported improvement in anxiety symptoms, 36.3% (73 of 201) reported minimal symptom change, and 14.9% (30 of 201) reported worsening of anxiety symptoms. No association was found between change in anxiety symptoms within the first 2 weeks and change in depressive symptoms or remission at the end of 8 weeks of treatment. For participants with clinically meaningful anxiety symptoms at baseline, however, worsening of anxiety during the first 2 weeks of treatment was associated with worsening depressive symptoms by 8 weeks (P5.054). Conclusions: The trajectory of anxiety symptom change early in SSRI treatment is an important indicator of eventual outcome for outpatients with major depression and baseline anxiety symptoms.