New research on the biological basis of addiction has found that the critical epigenetic enzyme histone deacetylase 5 (HDAC5) limits the expression of the gene Scn4b, regulating neuronal activity and thereby the formation of strong drug-related memories, which can trigger relapse in individuals with substance use disorders (SUDs). The study in Biological Psychiatry, published by Elsevier, detailing these epigenetic mechanisms in the brain, uncovers a new molecular target for the development of novel SUD treatments.

Opioid use disorder is associated with more than 350,000 deaths annually worldwide. Guided by the need for an increased understanding of critical neurobiological features of addiction, researchers have now found a unique molecular signature and genes in the orbitofrontal cortex associated with heroin-seeking behavior. A preclinical rodent model implicated a gene called Shisa7 as the key predictor. A new study in Biological Psychiatry, published by Elsevier, provides valuable insights into the neurobiological mechanisms underlying heroin addiction and may have implications for the development of innovative strategies to combat the ongoing opioid epidemic.

Researchers from the HIV Prevention Trials Network (HPTN) presented results from the HPTN 094 (“INTEGRA”) study at the 2025 Conference on Retroviruses and Opportunistic Infections (CROI) in San Francisco. The main findings from this randomized controlled trial that enrolled persons who inject drugs showed that similar numbers of participants were on medication for opioid use disorder (MOUD) and antiretroviral therapy (ART) for HIV care or prevention at 26 weeks post-randomization either to an intervention arm that provided integrated services with peer navigation in a mobile unit or to an active control arm that received navigation to integrated services at available community agencies only. Findings showed about seven percent of participants in both arms were determined as alive and on MOUD, about 35 percent of participants living with HIV were virally suppressed, and between three percent and five percent on HIV pre-exposure prophylaxis (PrEP) at 26 weeks post-randomization.