Inflammation as a predictive biomarker for response to omega-3 fatty acids in major depressive disorder: a proof-of-concept study

This study explores whether inflammatory biomarkers act as moderators of clinical response to omega-3 (n-3) fatty acids in subjects with major depressive disorder (MDD). One hundred fifty-five subjects with Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (DSM-IV) MDD, a baseline 17-item Hamilton Depression Rating Scale (HAM-D-17) score ⩾ 15 and baseline biomarker data (interleukin (IL)-1ra, IL-6, high-sensitivity C-reactive protein (hs-CRP), leptin and adiponectin) were randomized between 18 May 2006 and 30 June 2011 to 8 weeks of double-blind treatment with eicosapentaenoic acid (EPA)-enriched n-3 1060 mg day(-1), docosahexaenoic acid (DHA)-enriched n-3 900 mg day(-1) or placebo. Outcomes were determined using mixed model repeated measures analysis for 'high' and 'low' inflammation groups based on individual and combined biomarkers. Results are presented in terms of standardized treatment effect size (ES) for change in HAM-D-17 from baseline to treatment week 8. Although overall treatment group differences were negligible (ES=-0.13 to +0.04), subjects with any 'high' inflammation improved more on EPA than placebo (ES=-0.39) or DHA (ES=-0.60) and less on DHA than placebo (ES=+0.21); furthermore, EPA-placebo separation increased with increasing numbers of markers of high inflammation. Subjects randomized to EPA with 'high' IL-1ra or hs-CRP or low adiponectin ('high' inflammation) had medium ES decreases in HAM-D-17 scores vs subjects 'low' on these biomarkers. Subjects with 'high' hs-CRP, IL-6 or leptin were less placebo-responsive than subjects with low levels of these biomarkers (medium to large ES differences). Employing multiple markers of inflammation facilitated identification of a more homogeneous cohort of subjects with MDD responding to EPA vs placebo in our cohort. Studies are needed to replicate and extend this proof-of-concept work.

Similar changes in cognitions following cognitive-behavioral therapy or escitalopram for major depressive disorder: Implications for mechanisms of change

BACKGROUND

Psychosocial treatments and medications both have been shown to be effective in treating major depressive disorder. We hypothesized that cognitive-behavioral therapy (CBT) would outperform medication on measures of cognitive change.

METHODS

We randomized depressed individuals to 12 weeks of CBT (n = 15) or escitalopram (n = 11). In an intent-to-treat analysis (n = 26), we conducted a repeated measures analysis of variance to examine changes in depressive symptoms (ie, 17-item Hamilton Depression Rating Scale, Beck Depression Inventory), anhedonia (ie, Snaith-Hamilton Pleasure Scale), cognitive measures (ie, Dysfunctional Attitudes Scale, Automatic Thoughts Questionnaire, Perceived Stress Scale), and quality of life (ie, Quality of Life Enjoyment and Satisfaction Questionnaire) at 4 time points: baseline, week 4, week 8, and week 12. Treatment for both groups started at baseline, and patients received either 12 weeks of individual CBT or 12 weeks of escitalopram with flexible dosing (10 to 20 mg).

RESULTS

Collapsing the escitalopram and CBT groups, there were statistically significant pre-post changes on all outcome measures. However, there were no statistically significant differences between treatment groups on any of the outcome measures, including cognitive measures across time points.

CONCLUSIONS

Our results suggest that both CBT and escitalopram have similar effects across a variety of domains and that, in contrast to our a priori hypothesis, CBT and escitalopram were associated with comparable changes on cognitive measures.