Exploring the Connection Between Opioid Use and PTSD Risk: What You Need to Know

A Mouse Model Reveals Link Between Opioid Use and PTSD

Opioid Dependence and PTSD Risk

Recent research has established a significant connection between opioid use and the risk of developing post-traumatic stress disorder (PTSD). Findings indicate that opioid dependence prior to experiencing a traumatic event can heighten the likelihood of PTSD. Opioids are frequently employed in the management of physical injuries and pain, including discomfort resulting from trauma. Notably, approximately 35% of individuals diagnosed with PTSD also develop opioid dependence.

Investigating the Relationship Between Opioid Use and PTSD

A study published in the journal *Neuropsychopharmacology* examined whether prior opioid use exacerbates the risk of developing PTSD. Researchers aimed to deepen the understanding of the complex relationship between opioid use and PTSD.

To conduct this investigation, a stress-enhanced fear learning (SEFL) mouse model was utilized. This model is effective in simulating anxiety-like behaviors associated with trauma, reflective of PTSD symptoms. The researchers measured the duration of time the mice exhibited freezing behavior as an indicator of PTSD.

Study Design and Methodology

The experiment was structured to simulate substance use disorder (SUD). One group of mice received an increasing dose of morphine over an eight-day period, while a control group received a saline solution during the same timeframe. Following this, the mice underwent a one-week period without any substances to allow for the dissipation of potential acute withdrawal symptoms.

For the trauma aspect of the study, the mice were divided into trauma and non-trauma subsets. On the first day, the trauma group was placed in a box and subjected to mild foot shocks, while the non-trauma group remained in the box without shocks for the same duration. On the second day, both groups were reintroduced to the box, and their anxiety-like behavior was evaluated through freezing duration. The results indicated that the freezing times for both the morphine trauma group and the saline trauma group were comparable.

On the third day, the mice were placed in a different environment, and the trauma group received another set of mild foot shocks. Upon returning to this new environment on the fourth day, the morphine trauma group exhibited significantly higher freezing behavior compared to the saline trauma group. Interestingly, the morphine non-trauma group did not display increased freezing in this part of the experiment.

Additional Findings on Timing of Morphine Administration

Researchers conducted an additional experiment to assess the effects of morphine administration at a different stage in the timeline. In this instance, morphine was administered after the initial shock rather than before it. The results showed that the morphine trauma group did not exhibit increased freezing, contrasting with the previous findings where pre-shock morphine treatment correlated with heightened freezing in the trauma group.

Conclusion and Implications

This study underscores the critical insight that individuals with opioid dependence prior to a traumatic event are at a greater risk of developing PTSD. The authors advise caution regarding the chronic use of opioids for managing pain and physical injuries, as subsequent trauma could potentially elevate the risk of PTSD.

References

Pennington, Z.T., Trott, J.M., Rajbhandari, A.K. et al. Chronic opioid pretreatment potentiates the sensitization of fear learning by trauma. (2019) doi:10.1038/s41386-019-0559-5
EurekAlert!. (2019). Chronic opioid treatment may increase PTSD risk. [online] Available at: https://www.eurekalert.org/pub_releases/2019-12/s-cot112719.php [Accessed 4 Dec. 2019].
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