These findings have led to additional studies examining other approaches that block or normalize pro-inflammatory cytokines. A large-scale survey showed that etanercept, a soluble TNFα receptor that binds to TNFα and inhibits it’s interaction with cell-surface receptors, relieves fatigue and some symptoms of depression in patients being treated for psoriasis (Tyring et al., 2006). 3-hydroxy–3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) decrease cholesterol levels and are used to prevent or treat cardiovascular diseases, but are also reported to have antidepressant effects, possibly as a result of anti-inflammatory actions (Otte et al., 2012). Similarly, a meta-analysis of eicosapentaenoic acid (EPA), an omega-3 fatty acid with anti-inflammatory properties, shows that it has antidepressant actions (Block et al., 2012; Lin and Su, 2007). Ketamine, a rapid onset antidepressant and N-methyl-D-aspartate (NMDA) receptor antagonist, also possesses anti-inflammatory properties, although at doses higher than used for behavioral studies (Adams et al., 2008).
