Bases physiologiques communes pour les troubles de stress post-traumatique et la dépendance aux drogues d’abus : conséquences pour de nouvelles approches thérapeutiques

Effectiveness of drugs acting on adrenergic receptors in the treatment for tobacco or alcohol use disorders: systematic review and meta-analysis

AIM

To assess the efficacy of drugs directly acting on alpha- and beta-adrenergic receptors in the treatment of patients suffering from tobacco or alcohol use disorder.

METHODS

Using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, studies were identified through PUBMED, EMBASE, the Cochrane Central Register of Controlled Trials and clinicaltrial.gov. We selected only randomized controlled trials with adult patients with tobacco or alcohol use disorders according to DSM-5 criteria. Interventions included any molecule having a direct pharmacological action on alpha- or beta-adrenergic receptors (agonist or antagonist). Comparators were placebo or other validated pharmacotherapies. The duration of the intervention was a minimum of 1 month, with 3 months of follow-up. Measurements included smoking cessation for tobacco; for alcohol, we selected abstinence, alcohol consumption (drinks per day or week) and heavy drinking days (HDD). Ten studies with tobacco and six with alcohol use disorder were included in the qualitative synthesis and fifteen studies in the quantitative analysis.

RESULTS

We found that clonidine, an alpha-2 agonist, significantly increased smoking abstinence [relative risk = 1.39 with a 95% confidence interval (CI) = 1.04, 1.84]. Beta-blockers had no significant effect on smoking abstinence. The alpha-1 antagonists prazosin and doxazosin decreased alcohol consumption [SMD = -0.32 (-0.56, -0.07)] but had no effect on abstinence or HDD.

CONCLUSIONS

The noradrenaline system may represent a promising mechanism to target in tobacco and alcohol use disorders.

Critical considerations for the positive memory-posttraumatic stress disorder model

Posttraumatic stress disorder (PTSD) includes changes in processes such as encoding and retrieval for both traumatic and positive memories. However, most work has predominantly focused on traumatic memories. Thus, Contractor and colleagues proposed a Positive Memory-PTSD model, which highlighted potential benefits associated with and mechanisms underlying positive memory retrieval/processing among individuals reporting PTSD symptoms. To enhance research on and clinical impacts of this model, the current review provides critical considerations for the Positive Memory-PTSD model. Drawing from emerging research and clinical observations, we (i) clarify that the model addresses specific versus overgeneral positive memories; (ii) underscore the importance of considering the heterogeneity in, and transitionary nature of, affect processes following positive memory retrieval; and (iii) highlight the rationale for considering trauma type/count and co-occurring conditions, as potential moderators of relations between positive memory processing and PTSD. Hereby, we provide an updated Positive Memory-PTSD model and implications for positive memory interventions drawing from this model.

Post Traumatic Stress Disorder and Substance Use Disorder as Two Pathologies Affecting Memory Reactivation: Implications for New Therapeutic Approaches

In the present review, we provide evidence indicating that although post traumatic stress disorder (PTSD) and substance use disorder (SUD) are two distinct pathologies with very different impacts on people affected by these chronic illnesses, they share numerous common characteristics, present high rates of co-morbidity, and may result from common physiological dysfunctions. We propose that these pathologies result from hyper reactivity to reminders, and thus should be considered as two disorders of memory, treated as such. We review the different possibilities to intervene on pathological memories such as extinction therapy and reconsolidation blockade. We also introduce new therapeutic avenues directly indicate by our recent proposal to replace the consolidation/reconsolidation hypothesis by the integration concept. State dependency and emotional remodeling are two innovative treatments that have already provided encouraging results. In summary, this review shows that the discovery of reactivation-dependent memory malleability has open new therapeutic avenues based on the reprocessing of pathological memories, which constitute promising approaches to treat PTSD and SUD.

Re-traumatization Cycle: Sexual Abuse, Post-Traumatic Stress Disorder and Sexual Risk Behaviors among Club Drug Users

Background: Club drug users are high risk and vulnerable population for adverse drug-related consequences and sexual risk behaviors. Few investigations have addressed the possible interrelationship between early trauma and PTSD among young club drug using populations. Objective: Exposure to traumatic experiences - especially in childhood, has been linked to risk behaviors exposure and substance use disorder. This study aimed to assess and compare drug use patterns and the presence of childhood sexual abuse (CSA) experiences among ecstasy and LSD users with and without Posttraumatic Stress Disorder (PTSD). Method: This cross-sectional study employed targeted sampling and ethnographic mapping approaches via face-to-face interviews conducted at bars and electronic music festivals. The Global Appraisal of Individual Needs questionnaire was used as the primary assessment instrument. Participants were from 18 to 39 years of age, had used ecstasy and/or LSD in the 90 days prior to the interview, and were not in treatment for alcohol and other drug problems. Results: Out of the 240 participants, 123 (51.2%) presented PTSD symptoms. Those presenting PTSD were younger, less educated, with lower income, and presented higher drug use severity than those without PTSD symptoms. Moreover, a higher prevalence of sexual risk behavior was verified among those with PTSD. There was an association between PTSD symptoms and CSA history, where 64.2% of individuals with PTSD also presented CSA, compared to 47% among those without PTSD (p = .028). Individuals with co-occurring history of CSA and PTSD symptoms reported earlier use of ecstasy, LSD, and cocaine compared to individuals with a history of CSA but without PTSD. Conclusions: In the present study, participants with a history of PTSD demonstrate a history of CSA, as well as pronounced severity in several areas - precocity of use, severity of addiction, and greater exposure to situations of sexual risk. Thus, a cycle of traumatization may be established through early potential trauma, which can remain unprocessed and contribute to earlier and more severe substance use and sexual risk behaviors. Identification of PTSD symptoms and risk for HIV and other STIs among young club drug users is critical to address focused treatment approaches for this vulnerable population.

Behavioral and Noradrenergic Sensitizations in Vulnerable Traumatized Rats Suggest Common Bases with Substance Use Disorders

The aim of the present study was to strengthen our hypothesis of a common physiological basis for post-traumatic stress disorder (PTSD) and substance use disorders. This paper investigates the possibility that rats exposed to a PTSD model exhibit noradrenergic and behavioral sensitization, as observed following repeated drugs of abuse injections. First, rats received a single prolonged stress (SPS), combining three consecutive stressors. They were then tested, 2 weeks after the trauma for PTSD-like symptoms to discriminate between vulnerable and resilient rats. When microdialysis was performed in the prelimbic cortex (Experiment 1), larger increases of noradrenaline (NA) release in response to amphetamine were observed in vulnerable rats when compared to control and resilient animals. Experiment 2 showed that trauma-vulnerable rats exhibited increases in locomotor activity relative to controls, in response to an exposure to trauma-associated cues. These data demonstrate that a single trauma exposure induces in vulnerable animals both, a noradrenergic sensitization evidenced within the prelimbic cortex and behavioral sensitization obtained after a physiologic activation of the noradrenergic system. However, Experiment 3 showed that when NA system was activated by amphetamine (1 mg/kg), a decrease in behavioral sensitization was obtained in vulnerable rats. We proposed that this decreased locomotor activity results from an additional stress-induced increased reactivity of mesocortical dopaminergic neurons, known to counteract the consequences of cortical noradrenergic release in rats. These results support our hypothesis that noradrenergic sensitization represents a common physiological basis, involved both in PTSD and drug addiction and suggest new common therapeutic approaches for these pathologies.