A Breakthrough in Domestic Violence Prevention: The REINVEST Trial

Domestic violence remains one of Australia's most pressing social crises. In April 2024, Prime Minister Anthony Albanese declared it a "national crisis", calling for proactive interventions that focus on perpetrators and prevention. Now, groundbreaking research from New South Wales offers a promising new approach using a common antidepressant that could help reduce domestic violence reoffending amongst highly impulsive men.

The World-First REINVEST Study

The REINVEST trial (REducing Impulsivity IN Repeat ViolEnt Offenders Using a Selective Serotonin Reuptake Inhibitor) represents a world-first investigation into whether medication can reduce violent behavior. Conducted by researchers from the University of New South Wales and the University of Newcastle, the study screened 1,738 men between 2013 and 2021, with 630 ultimately participating in the randomised, double-blind trial.

Participants received either sertraline (a commonly prescribed antidepressant) or a placebo. Neither the participants nor the clinical team knew who received which treatment, ensuring the integrity of the results. Most participants were recruited through community corrections offices and courts across NSW, and approximately 80 per cent had a history of domestic violence offending.

Promising Results for Domestic Violence Reduction

While the trial's results for general violence were inconclusive, the findings for domestic violence were significant. At 12 months, domestic violence reoffending was lower in the sertraline group at 19.1 percent compared to 24.8 percent in the placebo group. This represents a meaningful reduction in harmful behavior that could protect countless women and children from abuse.

The impact extended beyond reoffending rates. During an initial four-week period before randomisation, when all participants received sertraline, researchers observed behavioral changes that occurred before most psychosocial supports could take full effect, demonstrating the medication's direct impact.

The Science Behind the Intervention

Why does sertraline specifically help with domestic violence? The medication works by enhancing serotonin functioning in the brain, which plays a crucial role in regulating impulse control and emotional responses. For highly impulsive men, this directly addresses a key driver of violence: the inability to pause and regulate emotional reactions.

Domestic violence frequently involves emotionally charged, impulsive reactions in intimate relationships, and the type of anger and aggression in these reactive contexts is theorised to be most responsive to regulating brain serotonin neurotransmission. General violence, by contrast, is more diverse and may include premeditated acts that are less reactive in nature.

The scientific foundation for this approach isn't new. Research has established a strong relationship between aggression, impulsivity, and serotonergic dysfunction. A 2010 pilot study preceded REINVEST and showed reductions in impulsivity, irritability, anger, and various forms of assault following SSRI treatment.

Real-World Impact: Voices from Partners and Family

Perhaps the most powerful testament to the trial's effectiveness comes from the women whose lives were directly affected. Researchers conducted in-depth interviews with 27 women (partners and family members of trial participants) living in New South Wales.

Most women, 92.3 per cent, reported some or significant changes in impulsivity and domestic violence or intimate partner violence following the participation of related men in the trial. Many changes were observed at multiple levels: individual self-regulation, family feelings of safety, and even social improvements like employment.

Overall, 96 per cent of partners reported maintained or increased safety, 85 per cent observed positive behavioural changes in the men, and 77 per cent reported improved personal wellbeing.

The qualitative feedback was striking. One participant described his transformation: "I've evolved... I was actually stepping back and listening to what other people had to say before I blew my top." Even more poignantly, one partner shared: "I used to sleep with a hammer under my bed. Since he started this medication, I can sleep more easily, and I don't need to sleep with the hammer any more."

The Critical Role of Comprehensive Support

The researchers emphasise that medication alone isn't a silver bullet. Analysis revealed the benefit of sertraline in reducing impulsivity and domestic violence when supported with other interventions such as counseling and follow-up support by clinicians.

The findings reveal a key relationship: sertraline improves a range of behavioral measures and reduces impulsivity, while comprehensive psychosocial support addresses the trauma, social disadvantage, and unmet needs that maintain patterns of emotional reactivity and violence.

This integrated approach is crucial. Many men in the trial had extensive trauma histories, with childhood abuse being common. Addressing these underlying factors through counselling and support amplifies the medication's benefits and helps create lasting behavioural change.

Cost-Effectiveness and Practical Implementation

Beyond its effectiveness, the REINVEST model offers significant economic advantages. The approach costs about $7,000 per participant annually versus $150,000 for incarceration. This dramatic cost difference makes it an attractive option for governments seeking evidence-based interventions.

The model's independence from mainstream government services proved crucial for engagement. Operating through a university research program rather than government systems helped build trust with men who had extensive negative experiences with institutions. This structural element may be as important as the medical intervention itself.

NSW Government Investment in Violence Prevention

The REINVEST trial has been part of broader NSW Government efforts to combat domestic violence. The NSW Government invested more than $431 million over four years to deliver initiatives working towards reducing domestic violence reoffending by 25 percent. REINVEST was included among evidence-based programs targeting persistent offenders.

More recently, the NSW Government has continued to expand its commitment. The 2025-26 Budget includes substantial justice system investments, with $272.7 million for frontline domestic, family, and sexual violence services. However, advocates have expressed concerns that much of this represents continuation of existing funding rather than new investment to meet soaring demand.

Limitations and Considerations

While the results are promising, the researchers acknowledge this isn't a complete solution. The intervention is designed for a specific population: highly impulsive men with histories of violent offending. It's one tool in a comprehensive ecosystem of domestic violence prevention strategies.

The study also highlights the complexity of violence reduction. The medication showed clear effects on domestic violence but inconclusive results for general violence, suggesting that different types of violence may require different interventions.

Looking Forward: Prevention Before Harm

What makes the REINVEST trial truly groundbreaking is its preventive approach. Rather than solely focusing on supporting victims after violence occurs, this intervention aims to prevent harm before it happens. By addressing the neurobiological and psychological factors that drive impulsive violence, combined with comprehensive support services, it offers a pathway to interrupt cycles of abuse.

As domestic violence continues to affect millions of Australians, evidence-based interventions that can reduce reoffending deserve serious consideration. The REINVEST trial demonstrates that when we help men address the psychological, relational, and social factors driving their violent behavior, meaningful change is possible.

The research offers hope, not as a magic solution, but as a proven, cost-effective intervention that could be implemented now as part of a broader strategy to build safer communities and protect vulnerable women and children from violence.

The REINVEST trial was conducted by the Kirby Institute at the University of New South Wales in partnership with Justice Health New South Wales and received funding from the National Health and Medical Research Council. The research has been published in peer-reviewed journals and represents years of collaborative work across justice, health, and academic sectors.