1. Why this matters: ADHD as an under-treated chronic condition
ADHD is one of the most common psychiatric conditions of childhood and adolescence, with a prevalence of roughly 9-11% in U.S. youth and 4-5% in adults. It is also one of the most under-treated. Across U.S. data, somewhere between one-third and one-half of children and adolescents with ADHD are not receiving evidence-based treatment in any given year, and the proportion drops further among adults, women, and racial and ethnic minority populations. (See ADHD prevalence and epidemiology for the underlying numbers.)
This matters because ADHD is not a benign condition that resolves on its own. Roughly 60-70% of children with ADHD continue to meet impairment criteria into adulthood, and even those who no longer meet full diagnostic criteria often retain executive-function deficits that drive measurable downstream harm. The aggregate burden of untreated ADHD - in suicide, accidents, criminal convictions, school failure, substance use, and premature mortality - is large enough to be visible at population scale.
This page reviews that population-scale evidence. The anchor study is one I co-authored: a 2021 analysis of the National Comorbidity Survey Adolescent Supplement (NCS-A), published in the Journal of Adolescent Health. Subsequent sections discuss how that finding fits with the broader literature, what mechanisms appear to drive the cascade, and what changes when treatment is initiated.
2. The anchor study: Sultan et al., J Adolesc Health 2021
Sultan RS, Liu SM, Hacker KA, Olfson M. Adolescents With Attention-Deficit/Hyperactivity Disorder: Adverse Behaviors and Comorbidity. Journal of Adolescent Health. 2021;68(2):284-291. doi:10.1016/j.jadohealth.2020.09.036
Design
We analyzed the National Comorbidity Survey Adolescent Supplement (NCS-A), a nationally representative U.S. survey of 6,483 adolescents aged 13-18 with face-to-face structured diagnostic interviews. Lifetime ADHD diagnoses and adverse outcomes were assessed prospectively. We computed adjusted odds ratios comparing adolescents with ADHD (n=617, 9.5% of the sample) to peers without ADHD, adjusting for age, sex, race/ethnicity, family income, and parental education.
Findings
| Outcome | Adjusted Odds Ratio (95% CI) | Plain-language interpretation |
|---|---|---|
| Suicide attempt | 2.9 (1.3-6.6) | Adolescents with ADHD were nearly three times as likely to have attempted suicide. |
| Suicidal thoughts | 23.1% vs 11.0% (raw) | More than twice the prevalence of suicidal ideation. |
| Anger attacks with loss of control | 2.3 (1.7-3.2) | Roughly double the risk of physical aggression or property destruction. |
| School or job expulsion | 3.3 (1.7-6.5) | Adolescents with ADHD were 3.3x more likely to be expelled from school or terminated from a job. |
| School suspension | 4.1 (3.1-5.4) | More than four times the risk of suspension - the most consistent educational signal. |
| Alcohol use problems | 1.9 (1.2-2.9) | Nearly double the odds of meeting criteria for problematic alcohol use. |
| Cannabis use | 2.2 (1.7-2.9) | Cannabis use risk more than doubled. |
| Cocaine use | 2.6 (1.1-6.2) | Cocaine use 2.6x more likely. |
| Non-prescribed prescription drug use | 2.6 (1.5-4.7) | Including misuse of opioids and stimulants obtained without a prescription. |
| Any comorbid mental health disorder | 69.5% vs 40.8% (raw) | Roughly seven in ten adolescents with ADHD had at least one additional mood, anxiety, disruptive behavior, or substance use disorder. |
What this study added
Three things distinguish this analysis from prior work. First, the NCS-A is a nationally representative U.S. sample with structured diagnostic interviews, not a clinic-referred or registry-only cohort - so the effect sizes are not inflated by referral bias. Second, the comorbidity figure (69.5% with at least one additional psychiatric disorder) is high enough that ADHD without comorbidity is the exception, not the rule. Third, the educational outcomes (suspension aOR 4.1, expulsion aOR 3.3) are large in absolute terms and show up early enough in adolescence to plausibly mediate later occupational, financial, and substance-use outcomes.
3. Supporting literature: the consistency of the signal
The Sultan 2021 findings sit inside a broader literature that has reached the same conclusion from multiple angles - registry data, prospective cohorts, twin studies, and within-individual designs. The signal is unusually consistent.
Mortality (Dalsgaard, Lancet 2015)
A Danish national cohort of 1.92 million individuals followed from 1981-2013 found all-cause mortality rate ratios of 2.07 (95% CI 1.70-2.50) for individuals with ADHD compared to peers. The excess was driven primarily by accidents. Mortality risk was higher in individuals diagnosed in adulthood than in childhood - consistent with later diagnosis being a marker of longer untreated exposure.
Criminality (Lichtenstein, NEJM 2012)
Using Swedish registry data on 25,656 patients with ADHD followed across periods on and off medication, Lichtenstein and colleagues showed within-individual reductions in criminal conviction rates of 32% in men and 41% in women during medicated months compared to non-medicated months from the same individuals. The within-person design rules out many confounders. Untreated ADHD is associated with substantially higher criminal conviction risk; treatment substantially mitigates it.
Motor vehicle crashes (Chang et al., 2017)
Using both Swedish and U.S. data, Chang and colleagues showed that ADHD medication is associated with 38-42% lower motor vehicle crash rates in within-individual analyses. Untreated ADHD is a meaningful driver of road safety risk, especially among young adult men.
Substance-related emergency events (Quinn et al., 2017)
A within-individual analysis of 2.99 million U.S. patients with ADHD (MarketScan) found 31-35% lower substance-related emergency department visits during medicated months. The pattern is robust across women and men, adults and adolescents.
Course and persistence (Faraone & Larsson, 2019)
The most thorough recent review of ADHD heritability and longitudinal course concluded that ADHD is a chronic condition for the majority of affected children, with persistence into adulthood in 60-70% of cases when measured by impairment criteria. Untreated ADHD does not "burn out" reliably with maturation.
Adolescent functioning (Biederman et al., long-term follow-ups)
Multiple prospective cohorts (Biederman, MTA follow-up, Milwaukee) consistently show that adults whose childhood ADHD went untreated, or was treated only briefly, have lower educational attainment, higher unemployment, more relationship instability, and higher psychiatric comorbidity than treated peers - even after accounting for baseline severity.
4. Mechanism: why untreated ADHD compounds
ADHD is fundamentally a disorder of self-regulation: of attention, response inhibition, working memory, and emotional control. Each of these capacities underlies a different real-world behavior:
- Attention → school performance, sustained work, driving, listening in relationships
- Response inhibition → impulsive substance use, impulsive aggression, impulsive spending, impulsive sexual decisions
- Working memory → carrying out multi-step plans, holding rules in mind under temptation
- Emotional regulation → tolerating frustration, recovering from setbacks, avoiding rumination and depression
When these capacities are impaired and untreated, the downstream costs do not stay neatly in one domain. Poor school performance feeds unemployment, unemployment feeds substance use, substance use feeds depression and accidents, and so on. This is what we mean clinically when we say untreated ADHD compounds: the deficits are upstream of behavior in many domains, so even modest impairment yields visible harm across years.
For the underlying neuroscience - dopamine, prefrontal cortex, default-mode network dysregulation - see the dedicated ADHD Neuroscience page. The point for this review is simply that the cascade is biologically plausible and the population-level data are consistent with it.
5. What changes with treatment
The same datasets that document the harms of untreated ADHD also document substantial reductions in those harms during periods of treatment. The single most informative recent study is a Swedish self-controlled case series of 247,420 individuals with ADHD followed from 2006-2020 (Li et al., 2024), reviewed in our 2025 JAMA Psychiatry editorial:
Within-individual reductions during medicated periods (Li 2024 / Sultan 2025)
- Criminal convictions: ↓ 41% in women, 32% in men
- Substance-related emergency events: ↓ 31% in women, 35% in men
- Motor vehicle crashes: ↓ 42% in women, 38% in men
- Suicidal behavior: meaningful reduction in within-individual analyses
Within-individual design controls for stable confounders (genetics, family environment, baseline severity). The same person is compared to themselves across periods on vs off medication.
For the full treatment-side review - including cardiovascular safety, the substance-use "gateway" question, pediatric vs adult prescribing patterns, and what to do when pharmacology fails or harms - see the companion page:
Read the companion review
How ADHD pharmacology changes the natural course of the disorder - safety, efficacy, and what the population data show about treated versus untreated outcomes.
ADHD Pharmacology & Natural Course →6. Frequently asked questions
What happens if ADHD is left untreated?
Population studies show significantly higher rates of suicide attempts, substance use disorders, school suspension and expulsion, job loss, motor vehicle crashes, criminal convictions, and premature mortality. The Sultan 2021 NCS-A analysis quantified each of these in a nationally representative U.S. adolescent sample.
Does untreated ADHD cause depression?
Untreated ADHD does not cause depression in a one-to-one sense, but adolescents with ADHD have substantially higher rates of comorbid mood disorders. In the NCS-A, 69.5% of adolescents with ADHD had at least one comorbid mental health condition (vs 40.8% of peers). The chronic functional impairment of untreated ADHD is a likely contributor.
Can adults with untreated ADHD develop substance use disorders?
Yes. Adolescents with ADHD have 1.9x higher odds of alcohol use problems, 2.2x higher odds of cannabis use, 2.6x higher odds of cocaine use, and 2.6x higher odds of non-prescribed prescription drug use compared to peers. Risk persists into adulthood. See the related ADHD and Substance Use page.
Is untreated ADHD linked to suicide?
Yes. Adolescents with ADHD report suicidal thoughts at more than twice the rate of peers (23.1% vs 11.0%) and have adjusted odds of suicide attempts at 2.9x. Treatment is associated with reduced suicidal behavior in within-individual analyses.
Does untreated ADHD shorten life expectancy?
Yes. Dalsgaard et al. (Lancet 2015) found all-cause mortality approximately doubled among individuals with ADHD across a 1.92 million-person Danish cohort, driven primarily by accidents.
What is the natural course of untreated ADHD?
Roughly 60-70% of children with ADHD continue to meet impairment criteria into adulthood. Symptoms often shift presentation (less hyperactivity, more inattention and executive dysfunction) but functional impairment persists.
Can ADHD go away on its own?
For a minority of children, symptoms attenuate enough by adulthood to no longer meet diagnostic criteria. For the majority, symptoms and impairment persist. Waiting for ADHD to "resolve" is not an evidence-based strategy in the face of measurable population-level harms.
Why does untreated ADHD lead to so many bad outcomes?
ADHD is a disorder of self-regulation. The capacities it impairs - attention, inhibition, working memory, emotional control - underlie daily functions like driving, studying, holding a job, regulating mood, and avoiding impulsive substance use. When self-regulation is impaired and untreated, the downstream costs compound across years.
References
- Sultan RS, Liu SM, Hacker KA, Olfson M. Adolescents With Attention-Deficit/Hyperactivity Disorder: Adverse Behaviors and Comorbidity. J Adolesc Health. 2021;68(2):284-291. doi:10.1016/j.jadohealth.2020.09.036
- Dalsgaard S, Østergaard SD, Leckman JF, Mortensen PB, Pedersen MG. Mortality in children, adolescents, and adults with attention deficit hyperactivity disorder: a nationwide cohort study. Lancet. 2015;385(9983):2190-2196. doi:10.1016/S0140-6736(14)61684-6
- Lichtenstein P, Halldner L, Zetterqvist J, et al. Medication for attention deficit-hyperactivity disorder and criminality. N Engl J Med. 2012;367(21):2006-2014. doi:10.1056/NEJMoa1203241
- Chang Z, Quinn PD, Hur K, et al. Association between medication use for attention-deficit/hyperactivity disorder and risk of motor vehicle crashes. JAMA Psychiatry. 2017;74(6):597-603. doi:10.1001/jamapsychiatry.2017.0659
- Quinn PD, Chang Z, Hur K, et al. ADHD medication and substance-related problems. Am J Psychiatry. 2017;174(9):877-885. doi:10.1176/appi.ajp.2017.16060686
- Faraone SV, Larsson H. Genetics of attention deficit hyperactivity disorder. Mol Psychiatry. 2019;24(4):562-575. doi:10.1038/s41380-018-0070-0
- Sultan RS, Saunders DC, Veenstra-VanderWeele J. Protective effects of ADHD medication on real-world outcomes. JAMA Psychiatry. 2025. doi:10.1001/jamapsychiatry.2025.0918
- Li L, Zhu N, Zhang L, et al. ADHD pharmacotherapy and mortality and other adverse outcomes (Swedish self-controlled case series). 2024.
Considering treatment for yourself or a loved one?
Dr. Sultan provides ADHD evaluation and pharmacologic management at Columbia University Medical Center in New York City.
Request Consultation Read: How treatment changes the courseAbout Dr. Ryan Sultan
Dr. Ryan Sultan is Assistant Professor of Clinical Psychiatry at Columbia University Irving Medical Center, Director of the Sultan Lab for Mental Health Informatics, and a board-certified Adult and Child/Adolescent psychiatrist. His research focuses on two questions: (1) what happens to people with untreated ADHD, and (2) how pharmacologic treatment changes that trajectory.
His 2021 Journal of Adolescent Health study (the anchor paper for this review) quantified the adverse-outcome burden of untreated ADHD using a nationally representative U.S. sample. His 2025 JAMA Psychiatry analysis with Saunders and Veenstra-VanderWeele documented how medication reduces criminal convictions, substance-related emergency visits, and motor vehicle crashes by 30-42%. He holds an NIH NIDA K12 award and is the senior author of the 2019 JAMA Network Open study on antipsychotic use in youth with ADHD (440+ citations).