Top Findings on Addiction in 2024

Substance use disorders (SUDs) represent a global challenge, profoundly affecting individuals, families, and communities. Nevertheless, researchers are making considerable progress in understanding and treating addictions. Of the thousands of peer-reviewed reports published each year, this post highlights 10 of the top articles published in 2024, along with references to my relevant Psychology Today blog posts, providing more detail.

1. Tanz LJ, et al. Routes of Drug Use Among Drug Overdose Deaths—United States, 2020-2022. Morbidity and Mortality Weekly Report

Preliminary data indicate that. drug overdose deaths in the United States surpassed 109,000 in 2022; nearly 70% of deaths involved synthetic opioids other than methadone, primarily illegally manufactured fentanyl and fentanyl analogs. In addition, from January-June 2020 to July-December 2022, the percentage of overdose deaths with evidence of smoking drugs increased 73.7%, while the percentage with evidence of injection decreased 29.1%. Similar changes were observed in all U.S. regions. For the first time, smoking, rather than injecting, is increasing in popularity, and deaths from smoking fentanyl with or without methamphetamine or cocaine have surpassed deaths by injection. (See my post on this research.)

2. The HEALing Communities Study Consortium; Samet JH, et al. Community-Based Cluster-Randomized Trial to Reduce Opioid Overdose Deaths. New England Journal of Medicine

The HEALing Communities study identified 19 evidence-based recovery strategies to implement in the U.S. Discouragingly, this ambitious study did not prove that evidence-based interventions like distributing naloxone (Narcan) and providing access to medication-assisted treatments (MATs) significantly curbed opioid deaths. Instead, death rates were similar in the intervention group and control group. However, overdose death rates have been decreasing. The fentanyl overdose epidemic may be burning out because the most vulnerable have died, and survivors better understand risks. (See my post on this research.)

3. Todaro DR, et al. Collateral Damage: Neurological Correlates of Non-Fatal Overdose in the Era of Fentanyl-Xylazine. Neuroscience Insights

Opioid overdose reversal by friends, family, or the community has not been taken as a sentinel event. Non-fatal opioid overdoses are often ignored compared to a head injury with loss of consciousness, generally resulting in emergency room admission and workup. However, non-fatal overdoses are essential and are a cause of neurological injury due to hypoxia (insufficient oxygen).

Researchers at the University of Pennsylvania and the National Institute on Drug Abuse found smaller hippocampal volume in patients with a history of an overdose vs no overdose. The findings support an association between non-fatal opioid overdose and persistent brain and hippocampal injury.

The authors highlight considerations for clinical management of underappreciated neurological injury and cognitive dysfunction in patients with opioid use disorder (OUD) who overdose. (See my post on this research.)

4. Cherian KN, et al. Magnesium-ibogaine therapy in veterans with traumatic brain injuries. Nature Medicine

This prospective cohort study involving military veterans evaluated whether treatment with the psychedelic agent ibogaine was associated with significant improvement in disability scores, depression, and PTSD symptoms after one month. Although the study lacked randomization and a control group, the novel work of Nolan Williams, M.D. and his Stanford University group provides evidence for the possible efficacy of psychedelic compounds, in this case, plant-derived ibogaine, in treating very difficult-to-treat patients with traumatic brain injury, PTSD, addictions, and depression. (See my post on this research.)

5. Chan O, et al. Cannabis Use During Adolescence and Young Adulthood and Academic Achievement: A Systematic Review and Meta-Analysis. JAMA Pediatrics

Cannabis use during adolescence and young adulthood may affect academic achievement, but the magnitude of the association remains unclear. In this meta-analysis of 63 studies including 438,329 individuals, moderate-certainty evidence showed cannabis use during adolescence and young adulthood is probably associated with lower school grades, less likelihood of high school completion, university enrollment, or post-secondary degree attainment, and increased school dropout rate and school absenteeism. Further research is needed to mitigate factors associated with early cannabis exposure. (See my post on this research.)

6. Fitzgerald ND, et al. Sequencing hour-level temporal patterns of polysubstance use among persons who use cocaine, alcohol, and cannabis: A back-translational approach. Drug and Alcohol Dependence

The United States is currently in the "fourth wave” of an opioid overdose epidemic, marked by polydrug use. A study of more than 4 million patients testing positive for fentanyl found that 93% had ingested additional drugs. Among those using cocaine, 74% also used alcohol, and 38% used cannabis. Polysubstance use is highly prevalent among cocaine users. The most common pattern involved cocaine plus alcohol. Alcohol helps decrease cocaine’s side effects, and the combination creates a new drug, cocaethylene, itself a drug of abuse. (See my post on this research.)

7. Brand M, et al. Current Advances in Behavioral Addictions: From Fundamental Research to Clinical Practice. American Journal of Psychiatry

Marc Potenza, M.D. Ph.D. and his Yale research Group summarized current knowledge regarding five behavioral conditions: problematic gambling, gaming, sexual activity, shopping, and social media use. Only gambling disorder is recognized as a clinical disorder by the American Psychiatric Association. However, gaming and compulsive sexual behavior disorders have been recognized as clinical disorders by the World Health Organization. The authors recommend further investigation of the impact of modern technology.

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They note that many people suffering from internet-related disorders have co-occurring anxiety, depression, and attention-deficit/hyperactivity disorder, among other conditions. Affected individuals should receive access to treatment, including pharmacotherapy, psychotherapy, and neuromodulation. No medications have approved indications for behavioral addictions, and cognitive-behavioral therapy has been the mainstay of treatment. (See my post on this research.)

8. Galimberti M, et al. Genetic influences and causal pathways shared between cannabis use disorder and other substance use traits. Molecular Psychiatry

Yale researchers investigated genetic and causal relationships between cannabis use disorders (CUDs), lifetime cannabis use, and risks for developing substance use disorders (SUDs) . CUD and cannabis use differed in their relationships with SUDs and substance use traits. Among many significant findings, researchers found evidence that CUD and cannabis use may increase risks for other SUDs. A rise in the number of cannabis users may not only increase CUD and related harms but also may be expected to increase other problematic substance use. (See my post on this research.)

9. Siegel JS, et al. Psilocybin desynchronizes the human brain. Nature

Of the hallucinogens, psilocybin has shown the most consistent therapeutic effects, followed by ayahuasca, MDMA, and LSD. Washington University’s Josh Siegel administered a single dose of psilocybin to participants while tracking individual-specific brain changes with longitudinal precision functional brain mapping (roughly 18 magnetic resonance imaging visits per participant). Psilocybin massively disrupted functional connectivity (FC) in the cortex and subcortex, driven by brain desynchronization.

Psilocybin-driven FC changes were most potent in the default mode network, connected to the anterior hippocampus and thought to create our sense of space, time, and self. Persistent reduction of hippocampal-default mode network connectivity may represent a key aspect of the therapeutic effects of psychedelics. Psilocybin caused profound and widespread—yet not permanent—changes to the brain’s functional networks. This highly read breakthrough human study suggests a mechanism for psilocybin effects - it makes the brain more flexible and potentially more able to enter a healthier state. (See my post on this research.)

10. Krupa H, Gearhardt AN, Lewandowski A, Avena NM. Food Addiction. Brain Sciences

Researchers from Princeton, Michigan, and Columbia Universities reviewed the connection between drug addiction and overconsumption of highly palatable food. Are the exact biological mechanisms at work when a person overeats food, specifically foods refined or processed from their naturally occurring form? Behavioral similarities between food and drug addiction include loss of control when eating (bingeing), withdrawal, craving, sensitization, and cross-sensitization. There is consistent evidence overconsumption of highly palatable food changes brain chemistry in similar ways to drugs, leading to addiction. (See my post on this research.)