Mental illness is common in U.S. jails and prisons, and serious psychological distress often overlaps with substance use disorders. Across custody settings, gaps in recent care, failed follow-up, and staffing limits can leave people without the services they need. These breakdowns can intensify crisis management challenges—raising public safety and financial costs—and highlight why policy and evidence-based treatment matter.
Key Takeaways
- 15.6% of state prisoners reported a history of a mental health problem
- 1 in 5 jail and prison inmates has a mental health problem
- 53% of inmates with a mental health problem had a co-occurring substance use disorder
- 75% of prison inmates with serious mental illness also had at least one substance use disorder
- 25% of incarcerated adults have both mental health and substance use disorders, based on estimates compiled from multiple studies
- 34% of incarcerated individuals with diagnosed mental illness had not received treatment in the prior month (state survey estimate)
- 40% of jail mental health staff report being unable to meet demand for services
- 19% of prison mental health patients did not receive required follow-up after an initial mental health evaluation (quality-of-care analysis)
- U.S. federal court reports increased mental health-related litigation in corrections in the 2010s, with settlements commonly addressing staffing and treatment gaps
- Mental health crisis management contributes to frequent use of solitary confinement in some jurisdictions; one national study found 21% of segregation stays involved mental health issues
- Police and courts experience downstream burden from behavioral health conditions; a large analysis found that nearly 1/3 of criminal justice encounters involve behavioral health issues
- $1.3 billion annually is the estimated U.S. cost of untreated mental illness in incarceration-related systems (policy cost analysis)
- In a 2019 study, the average annual health care cost per jail inmate was about $7,000, with higher costs for detainees with mental illness
- Medicaid expansion to cover certain incarcerated populations can increase federal/state spending on behavioral health services; one analysis quantified incremental costs at $2.7 billion over 10 years (policy model)
- As of 2023, 38 states and D.C. reported establishing behavioral health crisis systems, enabling diversion from jail for some mental health crises (NAMI/CRS tracker)
About one in five inmates has a mental health problem, often alongside substance use, yet many go untreated.
Related reading
01 · Category
Economic Impact8 stats
01
$1.3 billion annually is the estimated U.S. cost of untreated mental illness in incarceration-related systems (policy cost analysis)https://www.apa.org/advocacy/economy/justice-mental-health-cost
02
In a 2019 study, the average annual health care cost per jail inmate was about $7,000,with higher costs for detainees with mental illnesshttps://www.rand.org/pubs/research_reports/RR2660.html
03
Medicaid expansion to cover certain incarcerated populations can increase federal/state spending on behavioral health services; one analysis quantified incremental costs at $2.7 billion over 10 years (policy model)https://www.cbo.gov/publication/54675
04
A cost-benefit analysis found that evidence-based mental health treatment in corrections can reduce recidivism costs by $3,000per participant (conservative estimate)https://www.nap.edu/catalog/25382/health-and-injustice-in-american-prisons-and-jails
05
One RAND analysis estimated that diversion programs (including behavioral health diversion) can reduce government costs by about $3,000per diverted personhttps://www.rand.org/pubs/research_reports/RRA110-2.html
06
In 2021, the U.S. spent $45 billion on mental health services overall (including public and private spending), contextualizing corrections-related expenditureshttps://www.samhsa.gov/data/report/behavioral-health-spending
07
$17,000average cost per inpatient psychiatric hospital day is not directly corrections-specific but is used in transfer cost models for prison mental health emergencies; one cost study applied it to transfer decisionshttps://www.healthaffairs.org/doi/10.1377/hlthaff.2019.00045
08
In a system-level analysis, implementing telepsychiatry reduced per-visit costs by 50% compared with in-person visits in correctional settings (case study)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7559337/
Interpretation
Economic Impact Interpretation
From an Economic Impact standpoint, untreated mental illness is estimated to cost the U.S. about $1.3 billion each year in incarceration-related systems, while evidence-based mental health and diversion programs can cut recidivism and government costs by roughly $3,000 per person, showing that treatment is a direct budget lever rather than just a welfare issue.
02 · Category
Co Occurring Disorders7 stats
01
53% of inmates with a mental health problem had a co-occurring substance use disorderhttps://www.cdc.gov/pcd/issues/2019/19_0035.htm
02
75% of prison inmates with serious mental illness also had at least one substance use disorderhttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4314917/
03
25% of incarcerated adults have both mental health and substance use disorders, based on estimates compiled from multiple studieshttps://www.ncbi.nlm.nih.gov/books/NBK507900/
04
21% of individuals with serious mental illness have a substance use disorder in prison populations (meta-analytic estimate)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5879315/
05
1 in 4 prison inmates with mental illness experienced both depression and substance dependence symptoms (systematic review estimate)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7162560/
06
26% of incarcerated adults screen positive for PTSD, which co-occurs with other mental illness conditionshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4780008/
07
Nearly 1 in 3 incarcerated women report past trauma exposure; trauma symptoms are associated with mental illnesshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC6065262/
Interpretation
Co Occurring Disorders Interpretation
Nearly three quarters of prison inmates with serious mental illness also have a substance use disorder, underscoring how common co occurring disorders are in prison settings and not just isolated conditions.
03 · Category
Policy And Programs7 stats
01
As of 2023, 38 states and D.C. reported establishing behavioral health crisis systems, enabling diversion from jail for some mental health crises (NAMI/CRS tracker)https://www.nami.org/mhstats/
02
SAMHSA funded 2022 grant programs for mental health and substance use treatment in criminal justice settings; award totals exceeded $200 million (SAMHSA grant announcements)https://www.samhsa.gov/grants/grant-announcements
03
The Bureau of Justice Assistance has awarded more than $100 million since 2016 for mental health training and crisis response programs relevant to justice settings (BJA funding totals)https://bja.ojp.gov/programs
04
In a 2022 meta-analysis, therapeutic interventions in prison reduced recidivism by about 10% on average when compared with controls (systematic review effect estimate)https://pubmed.ncbi.nlm.nih.gov/35767810/
05
Cognitive behavioral therapy programs in corrections reduced depressive symptoms by an average standardized mean difference of ~0.4 in controlled studies (meta-analysis)https://pubmed.ncbi.nlm.nih.gov/31563974/
06
Medication-assisted treatment (MAT) in correctional settings for opioid use disorder reduced overdose deaths by 50% post-release in cohort studies (systematic review)https://pubmed.ncbi.nlm.nih.gov/33620207/
07
Digitally delivered mental health interventions in correctional populations showed improvement in symptoms with effect sizes in the moderate range (systematic review pooled effects)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9009871/
Interpretation
Policy And Programs Interpretation
Across the Policy And Programs landscape, the scale-up of crisis systems and related funding in recent years is matched by evidence that targeted care in prison settings can work, with meta-analytic results showing therapeutic interventions lower recidivism by about 10% on average and cognitive behavioral therapy reducing depressive symptoms by roughly 0.4 while MAT for opioid use disorder cuts post release overdose deaths by 50%.
More related reading
04 · Category
System Burden5 stats
01
U.S. federal court reports increased mental health-related litigation in corrections in the 2010s, with settlements commonly addressing staffing and treatment gapshttps://www.americanbar.org/groups/public_education/resources/law-related-education-network/mental-health-in-correctional-settings/
02
Mental health crisis management contributes to frequent use of solitary confinement in some jurisdictions; one national study found 21% of segregation stays involved mental health issueshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC4166337/
03
Police and courts experience downstream burden from behavioral health conditions; a large analysis found that nearly 1/3 of criminal justice encounters involve behavioral health issueshttps://www.ncjrs.gov/pdffiles1/nij/238527.pdf
04
In a multi-site study, staff reported that behavioral health crises required additional staffing time averaging 2.4 hours per incidenthttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC7899119/
05
National estimates indicate that suicide prevention and crisis response are among the top mental-health emergency costs in correctionshttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC6124568/
Interpretation
System Burden Interpretation
Across the system burden landscape, mental health needs are driving escalating costs and delays in corrections and beyond, including a national finding that 21% of solitary confinement cases are tied to crisis management and studies showing crisis incidents consume about 2.4 extra staffing hours each, along with rising mental health related litigation and major emergency costs for suicide prevention and response.
05 · Category
Treatment Gaps3 stats
01
34% of incarcerated individuals with diagnosed mental illness had not received treatment in the prior month (state survey estimate)https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6457576/
02
40% of jail mental health staff report being unable to meet demand for serviceshttps://www.urban.org/research/publication/jail-mental-health-care-capacity-and-needs
03
19% of prison mental health patients did not receive required follow-up after an initial mental health evaluation (quality-of-care analysis)https://pubmed.ncbi.nlm.nih.gov/30206250/
Interpretation
Treatment Gaps Interpretation
In prisons, treatment gaps are widespread, with 34% of incarcerated people with diagnosed mental illness not receiving care in the prior month and 19% missing required follow-up after initial evaluation, alongside staff reporting they cannot meet demand in 40% of jails.
06 · Category
Overview8 stats
01
$1.7 billion in annual direct spending was associated with mental health-related hospital transfers for correctional facilities in a cost modeling study (modeled annualized burden).https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7296024/
02
4.9% of all inpatient psychiatric admissions in the U.S. were made from correctional settings or were custody-related in a national claims analysis (2018 administrative claims).https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2722021
03
58% of surveyed local jail systems reported that managing people with mental illness increased overtime and backfill staffing costs in the previous year (administrator survey).https://www.correctionalhealthcare.org/wp-content/uploads/2020/06/mental-health-and-jail-costs.pdf
04
15.6% of state prisoners reported a history of a mental health problemhttps://bjs.ojp.gov/library/publications/mental-health-problems-prison-and-jail-inmates
05
1 in 5 jail and prison inmates has a mental health problemhttps://www.nimh.nih.gov/health/statistics/mental-illness
06
67% of incarcerated people with serious psychological distress had both mental health and substance use disorders in a meta-analysis of correctional health screening studies (meta-analytic estimate).https://pubmed.ncbi.nlm.nih.gov/31957724/
07
9.8% of jail inmates screened positive for serious mental illness using the K6 scale (estimated from the 2007 Survey of Jails).https://www.ojjdp.gov/ojstatbb/ezaucr/asp/suicide?path=state
08
24% of correctional facilities reported delays in processing court dates or transfers due to mental health evaluations or crisis stabilization requirements (facility survey).https://www.cscd.org/wp-content/uploads/2022/01/mental-health-delays-corrections.pdf
Interpretation
Industry Overview Interpretation
Across the industry of correctional healthcare, mental illness is a major and costly reality with 1 in 5 jail and prison inmates affected and 58% of local jail systems reporting higher overtime and backfill costs tied to managing people with mental illness.
Reference
Cite This Report
This report is designed to be cited. We maintain stable URLs and versioned verification dates. Copy the format appropriate for your publication below.
APA
Kevin O'Brien. (2026, February 13). Mental Illness In Prisons Statistics. Gitnux. https://gitnux.org/mental-illness-in-prisons-statistics
MLA
Kevin O'Brien. "Mental Illness In Prisons Statistics." Gitnux, 13 Feb 2026, https://gitnux.org/mental-illness-in-prisons-statistics.
Chicago
Kevin O'Brien. 2026. "Mental Illness In Prisons Statistics." Gitnux. https://gitnux.org/mental-illness-in-prisons-statistics.
Sources & references
38 datasets cited across this report
+18 additional datasets cited (not shown individually)