How much of mass incarceration is a result of the war on drugs? Few questions about the justice system are more common — or harder to find clear answers to.
Only about 20% of incarcerated people — a small minority — are locked up for drug offenses. But the impact of the war on drugs can feel much larger. That's partly because police still make almost 1 million drug arrests each year, only some of which lead to prison sentences. It's also because a lack of treatment and options often leads people to be incarcerated for drug-related crimes.
The complex connections between drugs and punishment don't end there. Below is some of our key research putting the war on drugs into perspective — and highlighting some of its worst policy failures:
Key statistics:
Percentage of people incarcerated for drug offenses: 20% 1
Percentage of people who had a substance use disorder during the year before they went to prison: 47%2
Percentage of people who have received clinical treatment for substance use disorders while in prison: 10%3
Percentage of jail deaths attributable to drug and alcohol intoxication (overdose) in 2019: 15%4
Percentage of jails in which people can start medication-assisted treatment (MAT): 19%5
… in which people can continue medication-assisted treatment (MAT): 24%6
Percentage of people on probation with a substance use disorder and unmet treatment need: 68%7
Our report and data visualizations break down where people in the U.S. are incarcerated and why, including how many people are held in different facilities for drug offenses.
Our analysis of rare survey date shows how mass incarceration has been used to warehouse people with marginalized identities and those struggling with poverty, substance use disorders, and housing insecurity, among other serious problems.
A misguided policy from the War on Drugs suspends the driver's licenses of 175,000 people every year for drug offenses that do not involve driving. We're helping states repeal it.
Increasing drug sentences in school zones is meant to protect children, but has worsened racial disparities in state prisons. We've published three reports about why these geography-based penalties are ineffective and harmful.
Specialty courts: A disappointing form of diversion, by Leah Wang, February 2, 2026 It seems like specialty courts -- also called treatment courts, problem-solving courts, or accountability courts -- are everywhere, claiming to tackle the root causes of criminalized behavior while reducing the use of jails. But decades of research and advocacy suggest that these courts are no panacea, failing to adhere to best practices or prevent incarceration for many participants.
New study: Kids who need treatment for opioid use disorder rarely get it, by Brian Nam-Sonenstein, January 22, 2026 A new nationwide study published in Health Affairs finds that adolescents aged 12 to 17 struggle to access and remain engaged in treatment, often because they are not offered youth-tailored treatment and gold-standard opioid use disorder medications.
Estimating the impact: How many people are excluded from Fair Housing protections because of a past drug conviction?, by Wendy Sawyer, February 5, 2025 A little-known 1988 law called the Thurmond Amendment stripped people with drug distribution convictions of federal protections under the Fair Housing Act, making it even more difficult for many people with criminal records to secure housing - even when they are qualified in every other way, and even when the conviction is decades old. By our count, this law makes it more difficult for as many as 3 million people with these kinds of convictions to secure housing.
Oregon shouldn't go backwards on drug decriminalization, by Sarah Staudt, February 15, 2024 Oregon is in danger of repealing one of the most important criminal legal system reforms of recent years: here's why the state should keep Measure 110 intact.
Addicted to punishment: Jails and prisons punish drug use far more than they treat it, by Emily Widra, January 30, 2024 Despite the common refrain that jails and prisons are "de facto treatment facilities," most prioritize punitive mail scanning policies and strict visitation rules that fail to prevent drugs from entering facilities while providing little to no access to treatment and healthcare.
Seeking shelter from mass incarceration: Fighting criminalization with Housing First, by Brian Nam-Sonenstein, September 11, 2023 Providing unconditional housing with embedded services can reduce chronic homelessness, reduce incarceration, and improve quality of life - especially for people experiencing substance use disorder and mental illness.
Mortality, health, an poverty: the unmet needs of people on probation and parole, by Emily Widra and Alexi Jones, April 3, 2023 Unique survey data reveal that people under community supervision have high rates of substance use and mental health disorders and extremely limited access to healthcare, likely contributing to the high rates of mortality.
Seizing Chicago: Drug stings and asset forfeiture target the poor, by Alex Clark and Joshua Aiken, August 11, 2017 Instead of protecting Chicago's communities, state asset forfeiture practices and drug stings set up by federal agents target low-income, Black, and Latino residents, setting them up to fail.
The war on drugs is the most famous — but far from the only — criminal justice policy failure impacting public health. Our research sheds light on the public health effects of mass incarceration.
What does the war on drugs have to do with probation and parole? Plenty — from unjust supervision terms imposed on people who commit drug offenses to people on supervision who are incarcerated for a failed drug test.
Incarcerated women are more likely to be locked up for drug offenses — and more likely to suffer from substance use disorders — than men. Read more about incarcerated women and the injustices they face.
Beyond the Count: A deep dive into state prison populations
Ending driver's license suspensions for drug offenses unrelated to driving
Ending driver's license suspensions for drug offenses unrelated to driving
Combating racially imbalanced "sentencing enhancement zones"
Combating racially imbalanced "sentencing enhancement zones"
Public health
Public health
Probation and parole
Probation and parole
Women and gender
Women and gender
