Chronic opioid treatment may increase PTSD risk

(Springer) Long-term (chronic) treatment with opioids, such as morphine, prior to trauma enhances fear learning in mice, according to a study published in Neuropsychopharmacology. The findings, which link chronic opioid treatment before a traumatic event with responses to subsequent stressful events, may suggest a possible mechanism underlying the frequent co-occurrence of post-traumatic stress disorder (PTSD) and opioid dependence.