How expanding marriage rights affects mental health

Mental Health Effects of Marriage Policy: Evidence from Linked Administrative Data in New Zealand

NIH-funded research Vanderbilt University · NIH-11373167

Researchers will compare health records from before and after New Zealand expanded who can marry to see how that change affected anxiety, depression, self-harm, and substance-related problems for vulnerable groups.

Quick facts

Grant typeR01 grant
Study typeNIH-funded research
Funding institutionVanderbilt University NIH-funded
Lab location1 site (Nashville, UNITED STATES)
Project IDNIH-11373167 on NIH RePORTER

What this research studies

This project uses linked, nationwide New Zealand administrative records—including marriage registries, prescription data, mental health referrals, and hospital discharges—to study mental health trends around the 2013 change in marriage law. The team will compare outcomes over time and across groups using rigorous difference-in-differences and event-study methods to separate the law's effect from other trends. They will look at outcomes such as anxiety, depression, deliberate self-harm, substance abuse, and drug overdose and test whether effects differ by age, ethnicity, or other characteristics. The focus is on whether gaining legal access to marriage is associated with measurable changes in mental health for vulnerable populations.

Who could benefit from this research

Good fit: People included are New Zealand residents whose healthcare use appears in national administrative records, especially those who gained legal access to marry around the 2013 law change and members of vulnerable groups with anxiety, depression, or substance issues.

Not a fit: People who live outside New Zealand or whose care is not captured in national records would not be included and are unlikely to directly benefit from this project's data analysis.

Why it matters

Potential benefit: If the findings show mental-health improvements, they could support policies that reduce disparities and lower rates of self-harm and substance-related harms among affected groups.

How similar studies have performed: Some prior population studies suggest legal recognition can improve mental health for affected groups, but rigorous national-level causal analyses like this are relatively rare.

Where this research is happening

Nashville, UNITED STATES

Researchers

About this research

  1. This is an active NIH-funded research project — typically early-stage science, not a clinical trial accepting patient enrollment.
  2. Some NIH-funded labs run parallel clinical studies or seek volunteers for related work. To check, contact the principal investigator or institution listed above.
  3. For full project details, budget, and progress reports, visit the official NIH RePORTER page below.
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.