The Treatment of Substance Use Disorders: Recent Developments and New Perspectives

Doxycycline diminishes the rewarding and psychomotor effects induced by morphine and cocaine

Few pharmacological treatments are available for substance use disorders (SUDs). Neuroplastic changes induced by increased activity of metalloproteinase (MMP) enzymes in the brain are among the several molecular processes that may play a role in drug addiction. Doxycycline, a widely used tetracycline that crosses the blood-brain barrier, inhibits MMPs and has been investigated as a potential treatment for brain disorders. However, the effects of doxycycline on rewarding properties of drugs of abuse remain not investigated. Here, we tested the effects of low doses of doxycycline on the rewarding effects of morphine and cocaine in conditioned place preference (CPP) and locomotor sensitization in mice. Acute doxycycline (10 mg/kg) attenuated the cocaine-induced CPP and hyperlocomotion. Repeated doxycycline (10 mg/kg) blocked hyperlocomotion and attenuated the locomotor sensitization induced by cocaine. It also decreased the rewarding effects in the CPP induced by morphine and cocaine. Our results suggest that doxycycline could be repurposed for treating SUDs.

The Role of Estrogen Signaling and Exercise in Drug Abuse: A Review

BACKGROUND

Discovering how sex differences impact the efficacy of exercise regimens used for treating drug addiction is becoming increasingly important. Estrogen is a hormone believed to explain a large portion of sex differences observed during drug addiction, and why certain exercise regimens are not equally effective between sexes in treatment. Addiction is currently a global hindrance to millions, many of whom are suffering under the influence of their brain's intrinsic reward system coupled with external environmental factors. Substance abuse disorders in the U.S. alone cost billions of dollars annually.

REVIEW SUMMARY

Studies involving the manipulation of estrogen levels in female rodents, primarily via ovariectomy, highlight its impact regarding drug addiction. More specifically, female rodents with higher estrogen levels during the estrus phase increase cocaine consumption, whereas those in the non-estrus phase (low estrogen levels) decrease cocaine consumption. If estrogen is reintroduced, self-administration increases once again. Exercise has been proven to decrease relapse tendency, but its effect on estrogen levels is not fully understood.

CONCLUSIONS

Such findings and results discussed in this review suggest that estrogen influences the susceptibility of females to relapse. Therefore, to improve drug-abuse-related treatment, exercise regimens for females should be generated based on key sex differences with respect to males.

Equine-assisted therapy effectiveness in improving emotion regulation, self-efficacy, and perceived self-esteem of patients suffering from substance use disorders

Substance Use Disorders (SUD) is a universal overwhelming public health problem and is associated with other psychological and mental health ailments such as emotion regulation, perceived self-esteem, and self-efficacy problems. Complementary and alternative medicine may be beneficial. The aim of this study was to assess the effectiveness of equine-assisted therapy in improving emotion regulation, self-efficacy, and perceived self-esteem among patients suffering from substance use disorders. It was carried out using a randomized controlled trial design at Behman hospital, Cairo, Egypt. It included 100 patients suffering from SUD attending the setting, equally randomized into an intervention group to receive the equine assisted therapy and a control group to receive the regular care. Data were collected using a self-administered questionnaire with standardized tools for assessment of emotion regulation, General Self-Efficacy (GSE), and perceived self-esteem. The intervention group received weekly equine-assisted therapy sessions over 6 weeks in addition to their standard regular therapy. Patients in both groups had similar demographic and SUD characteristics, as well as baseline scores of reappraisals, suppression, GSE and perceived self-esteem. At post-intervention, the intervention group had significant improvements in all these scores in comparison with the control group, as well as their baseline. The multivariate analysis identified the study intervention as a significant positive predictor of the reappraisal and GSE scores, and a negative predictor of the suppression and perceived self-esteem negative score. In conclusion, equine assisted-therapy as a complementary treatment in patients suffering from SUD is effective in improving their emotion regulation, self-efficacy, and perceived self-esteem. A wider use of this approach is recommended in SUD patients along with provision of needed facilities and resources, and training nurses in its administration. Further research is proposed to assess its long-term effectiveness. The clinical trial was registered in the "Clinical Trials.gov Protocol Registration and Results System (PRS);" registration number is (05632185/2022) and the full date of first registration is 10/11/2022.

Be more mindful: Targeting addictive responses by integrating mindfulness with cognitive bias modification or cue exposure interventions

This review provides an overview of the most prominent neurocognitive effects of cognitive bias modification (CBM), cue-exposure therapy and mindfulness interventions for targeting addictive responses. It highlights the key insights that have stemmed from cognitive neuroscience and brain imaging research and combines these with insights from behavioural science in building a conceptual model integrating mindfulness with response-focused CBM or cue-exposure interventions. This furthers our understanding of whether and how mindfulness strategies may i) facilitate or add to the induced response-focused effects decreasing cue-induced craving, and ii) further weaken the link between craving and addictive responses. Specifically, awareness/monitoring may facilitate, and decentering may add to, response-focused effects. Combined awareness acceptance strategies may also diminish the craving-addiction link. The conceptual model presented in this review provides a specific theoretical framework to deepen our understanding of how mindfulness strategies and CBM or cue-exposure interventions can be combined to greatest effect. This is important in both suggesting a roadmap for future research, and for the further development of clinical interventions.