Ketamine's Antidepressant Effects Appear to Depend on Opioid System, Study Shows

The antidepressant effects of ketamine appear to depend on activation of the brain ’s opioid receptors, underscoring the drug’s addictive potential, according to areport published today inAJP in Advance.The study, by Alan Schatzberg, M.D. (pictured left), the Kenneth T. Norris Jr. Professor of Psychiatry and Behavioral Sciences at Stanford University School of Medicine, and colleagues, found that when patients with treatment-resistant depression were treated with the opioid antagonist naltrexone before receiving an infusion of ketamine, the antidepressant effects of ketamine were dramatically diminished.“While opioids have a history of use as antidepressants, they pose a significant risk if used chronically,” Schatzberg and colleagues wrote. “Thus, the abuse and dependence potential of frequent ketamine treatment in major depression needs further study, and our results provide strong justific ation for further caution against widespread and repeated use of ketamine before further mechanistic testing has been performed.”The researchers originally planned a crossover trial of 30 adults with treatment-resistant depression comparing a 0.5 mg/kg intravenous infusion of ketamine preceded by either oral placebo or oral naltrexone (50 mg). All participants were required to have a score of at least 20 on the 17-item Hamilton Depression Rating Scale (HAM-D). Each participant was also required not to have benefited sufficiently from trials of at least four antidepressant med...
Source: Psychiatr News - Category: Psychiatry Tags: addiction antidepressant depression ketamine opioid receptors opioid system suicide Source Type: research