Long-term (chronic) treatment with opioids, corresponding to morphine, previous to trauma enhances worry learning in mice, in line with a study published in Neuropsychopharmacology. The findings, which link persistent opioid treatment earlier than a traumatic occasion with responses to subsequent worrying occasions, could suggest a doable mechanism underlying the frequent co-occurrence of post-traumatic stress disorder (PTSD) and opioid dependence.
PTSD and substance use disorders (SUDs) usually happen collectively, with practically 40% of people with PTSD additionally having an SUD. This is named comorbidity, and understanding it might assist in clarifying the mechanisms by which these circumstances develop. Previous research has proven that PTSD will increase the danger of opioid dependence; however, whether or not opioid dependence can also improve PTSD danger remained unclear.
Utilizing a longtime model of fear learning in mice, researchers at the University of California, Los Angeles, USA, assessed the potential effect of continual opioid treatment on the subsequent improvement of PTSD-like behaviors. They discovered that mice that had been treated with opioids and later experienced stress confirmed extra pronounced put up-stress reactions.
Firstly, of the examine, mice had been treated with morphine or saline for eight days, followed by every week of drug cessation. Each team of mice—morphine-treated mice and saline-treated controls (22 and 24 mice, respectively) – had been then subdivided into trauma and non-trauma teams. They had been transferred to a chamber the place animals within the trauma group acquired a collection of gentle foot shocks. A day later, each team of animals had been returned to the chamber to evaluate their memory of the traumatic occasion.
The authors additionally examined treating mice with opioids after the initial trauma had occurred, however earlier than exposing them to the second, mild stressor.