Does ADHD Treatment Work in Adults? What the Major Studies Found

Claims about ADHD treatment tend to come without numbers, or with numbers that have no source. This page reports what the largest studies in adults found, in figures, and is equally specific about what those studies cannot tell you. It contains no dosing information and no recommendation for any individual. Drug names appear because the studies report results by drug.

How to read the numbers

Trial results below are given as a standardized mean difference (SMD), a way of putting different rating scales on one ruler. A negative SMD means symptoms fell more than with placebo. By a common convention, about 0.2 is called a small effect, 0.5 medium and 0.8 large. An SMD describes the average across a group. It does not predict how one person will respond.

Safety studies below report odds ratios or hazard ratios. A value of 1.0 means no difference. Those studies are observational: researchers compared people who did and did not take medication in health registers, without assigning treatment at random.

Medication: what randomized trials show

Two large pooled analyses carry most of the weight.

Cortese and colleagues, Lancet Psychiatry, 2018. A network meta-analysis of 133 double-blind randomized trials, 51 of them in adults, with 8,131 adults in the efficacy analysis.

Ostinelli and colleagues, Lancet Psychiatry, 2025. A component network meta-analysis of 113 randomized trials and 14,887 adults covering drugs, psychological therapies and neurostimulation.

The 2018 authors concluded that amphetamines were the preferred first choice in adults for short-term treatment, weighing efficacy against tolerability. Every active drug in the table was also stopped for side effects more often than placebo.

The 2025 analysis reported stimulants as a group at -0.39 on self-ratings and -0.61 on clinician ratings, and atomoxetine at -0.38 and -0.51. Only stimulants and atomoxetine reduced core symptoms on both kinds of rating. Atomoxetine and guanfacine were less acceptable than placebo, meaning more people dropped out.

Two findings from the 2025 paper deserve attention because they cut against marketing claims:

• Medication did not show a benefit on quality of life.
• Evidence beyond the short term was thin.

Both analyses measured outcomes at about 12 weeks. Neither supports a statement about how well any treatment works over years.

CBT and other psychological treatment

A 2018 Cochrane review pooled 14 randomized trials with 700 adults. CBT plus medication did better than medication alone on clinician-rated symptoms (SMD -0.80, from two studies with 65 participants). CBT did better than a waiting list on self-reported symptoms (SMD -0.84, five studies). The reviewers rated this low-quality evidence that CBT may be beneficial in the short term.

The 2025 analysis found that CBT (-0.76), mindfulness (-0.79), psychoeducation (-0.77) and cognitive remediation (-1.35) reduced symptoms on clinician ratings. None did so on patients' own ratings, and results were inconsistent between raters.

The fair reading: CBT helps, the trials are small, and the evidence is strongest for CBT added to medication. The data do not show that it works as well as medication. The site's article on treating ADHD without medication covers the non-drug approaches.

Mortality: the 2024 JAMA study

Li and colleagues followed 148,578 people in Sweden aged 6 to 64 who were newly diagnosed with ADHD between 2007 and 2018. About 57% started medication within three months. Over two years:

• All-cause mortality was 39.1 per 10,000 among those who started medication and 48.1 per 10,000 among those who did not (hazard ratio 0.79).
• Deaths from unnatural causes such as accidents, poisoning and suicide were lower (25.9 versus 33.3 per 10,000, hazard ratio 0.75).
• Deaths from natural causes did not differ significantly.

The median age at diagnosis was 17.4, so much of the group was young. The design was observational. Starting medication was associated with lower mortality. The study does not establish that medication prevents death.

Cardiovascular risk: the 2024 JAMA Psychiatry study

Zhang and colleagues used Swedish registers covering 278,027 people aged 6 to 64 with ADHD, comparing 10,388 who developed cardiovascular disease with 51,672 matched controls over a median 4.1 years.

• Compared with no use, the odds of cardiovascular disease were 0.99 for up to one year of cumulative use, 1.09 for one to two years, 1.15 for two to three years, 1.27 for three to five years and 1.23 beyond five years.
• Each additional year was linked to about 4% higher odds, concentrated in the first three years.
• The increase was driven by hypertension and arterial disease.

This is an association in a case-control study. It does not show that medication causes heart disease, and it does not show that medication is free of cardiovascular risk. Its practical message matches stimulant labeling, which tells prescribers to monitor blood pressure and pulse. More detail is in ADHD medication, heart health and blood pressure.

Psychosis and mania: the 2024 hospital study

Moran and colleagues studied patients aged 16 to 35 hospitalized at McLean Hospital between 2005 and 2019: 1,374 with a first episode of psychosis or mania and 2,748 admitted for other psychiatric reasons. Past-month use of a prescription amphetamine was associated with higher odds of psychosis or mania (adjusted odds ratio 2.68). The odds were highest at the top dose level studied. Methylphenidate showed no association (0.91).

The participants were young psychiatric inpatients, and the comparison group was also hospitalized. The study gives no absolute risk for a typical adult outpatient. Stimulant labels direct prescribers to screen for risk factors for mania before starting treatment. See ADHD or bipolar disorder?

What observational studies can and cannot show

People who start medication differ from people who do not: in severity, in other diagnoses, in access to care, in how closely they are followed. Statistical adjustment narrows those differences and never removes them. This is called confounding, and it applies to the reassuring mortality finding as much as to the cautionary cardiovascular one.

What this means for a treatment decision

Group averages inform a decision and do not make it. Response, side effects, other health conditions and personal priorities vary, which is why treatment is adjusted at follow-up. The practice's treatment page describes how medication management works, and the Treatment and Medication hub collects related articles.

The next step in this guide is a side-by-side look at the options: ADHD medications approved for adults in 2026.