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June 19, 2025
Background:
In Iceland, treatment with ADHD medication can only be initiated by psychiatrists or pediatricians with experience in diagnosing neurodevelopmental disorders. The diagnostic evaluation is most often carried out by a psychologist or psychiatrist, and must be confirmed by a psychiatrist.
Some previous studies have suggested a small but significant increased risk of psychosis or mania associated with ADHD medication, while others have not.
Iceland has a single-payer national healthcare insurance system that tracks virtually its entire population. An Icelandic research team accessed two administrative databases with nationwide coverage – the Icelandic Prescription Medicines Register and the Icelandic Hospital Discharge Register – to explore this relationship among all adults from 2010 through 2022.
They included three categories of ADHD medications prescribed in Iceland: amphetamines, including dexamphetamine and lisdexamphetamine; methylphenidate; and atomoxetine. In Iceland, methylphenidate or atomoxetine must be prescribed and tried first before switching to lisdexamphetamine or dexamphetamine.
Method:
Diagnoses of mania or psychosis recorded in electronic health records were used to identify individuals who were admitted to a psychiatric ward within one year of starting treatment with a specific class of ADHD medication. First-onset psychosis or mania was defined as the emergence of these conditions in individuals with no prior history, diagnosis, or hospitalization for psychosis or mania.
A total of 16,125 adults began using an ADHD medication for the first time during the 13-year study period.
Methylphenidate was the most used ADHD medication among those admitted for psychosis or mania (25 out of 61; 41%), reflecting its status as the most frequently prescribed stimulant during the study period. It was followed by amphetamines (21 out of 61; 34.4%) and atomoxetine (15 out of 61; 24.6%).
Half of those hospitalized had previously received a diagnosis of substance use disorder. One in nine (11%) of those hospitalized acknowledged misuse of the type of ADHD medication they had been prescribed.
Within a year of discharge, 42 out of the 61 patients (68.9%) had been prescribed an ADHD medication again. Among those, one in four (11 out of 42; 26%) were readmitted for psychosis or mania within the following year.
The team noted, “It is concerning that most patients (68.9%) in our study resumed ADHD drug treatment within a year of hospital discharge … However, some studies have reported that the use of psychostimulants or atomoxetine to treat ADHD in individuals with psychotic disorders did not increase the risk of hospitalisation for psychosis if used concurrently with antipsychotic medication or that such use might even reduce this risk.”
Findings:
By comparison with the general population, adults initiating ADHD medications had eight times the relative risk of being admitted for psychosis or mania within the first year.
The absolute risk was low: 0.38% overall for those initiating ADHD medication. Adjusting for the general population risk of hospitalization for first-onset psychosis or mania, more than 300 patients would need to be initiated to ADHD medication to generate one hospital admission for psychosis or mania.
The team conceded, “Confounders of real-life clinical settings, such as non-disclosed ADHD drug abuse or misuse or some degree of substance abuse, may have influenced our findings.”
A further, unmentioned, limitation is that the team did not perform any of the usual adjustments for confounding variables, critically including co-occurring (comorbid) psychiatric disorders known to be common with ADHD, and likely to have a major effect on the relative risk of hospitalization.
Given the very small increase in risk along with the methodological flaws, the team’s suggestion of a “potential causal role of ADHD drugs in the development of first-onset psychosis or mania” is unsubstantiated and speculative. This is especially so given other studies suggesting no increased risk for psychosis due to these medications.
In any event, causation cannot be established through observational studies.
Ragna Kristin Gudbrandsdottir, Engilbert Sigurdsson, Þorsteinn Ivar Albertsson, Halldora Jonsdottir, and Oddur Ingimarsson, “Risk of hospitalisation for first-onset psychosis or mania within a year of ADHD medication initiation in adults with ADHD,” BMJ Mental Health (2025), 28: 1–7, https://doi.org/10.1136/bmjment-2024-301521.
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The Background:
Because impulsivity is a core feature of ADHD, researchers have suggested it may raise the likelihood that someone will use psychoactive substances (including alcohol) and go on to develop a substance use disorder (SUD). When ADHD and SUD occur together in adolescents, treating one disorder alone usually has little or no positive effect on the other; current guidance therefore recommends treating both conditions at the same time using evidence-based approaches for each.
Given how much ADHD can worsen outcomes for people with primary SUDs, it is important to identify ADHD in people who are being treated for substance problems.
The Study:
A recent systematic meta-review found that, by current official criteria, ADHD affects about 7.2% of children and adolescents and about 2.6% of adults (Chaulagain et al., 2023). When adult ADHD is defined without the requirement that symptoms began by age 11, roughly 6.8% of adults meet criteria. A large body of research links ADHD to higher rates of medical problems, poorer quality of life, greater risk of suicide, more accidental injuries, worse educational outcomes, and increased involvement with the criminal justice system.
The present study is the first meta-analysis to estimate how common clinically diagnosed ADHD is among adults (age 18+) who are in treatment for psychoactive substance use disorders, and to provide those estimates by sex and by the specific substance used.
The authors included only studies of adults treated for a SUD (including alcohol). Eighty-four studies met the criteria, representing more than 34,000 people. Across all studies, the pooled prevalence of clinically diagnosed ADHD was 22%.
To put that in context, 22% is about eight times higher than the 2.6% adult prevalence using the stricter official definition, and about three times higher than the 6.8% rate when the childhood-onset requirement is relaxed. By substance, the prevalence was similar for alcohol (24%) and opioids (22%), with no significant difference between males and females. Prevalence among people treated for cocaine use was somewhat lower overall (18%), driven largely by lower rates among women, for whom the rate was no higher than in the general population. Estimates were higher for people using benzodiazepines and cannabis, but those figures are based on a very small number of users (256 and 249 people, respectively) and are therefore less certain.
The Results:
The authors conclude: “These findings underscore the need for early identification and treatment of ADHD as most substance use disorders develop in adolescence and young adulthood. While in treatment for ADHD, appropriate screening and management of substance use is possible.”
The Background:
Stimulant medications (like methylphenidate and amphetamines) and non-stimulants (like atomoxetine and guanfacine) remain the first-line treatments for ADHD, but their long-term use is often constrained by parental concerns, side effects (reduced appetite, sleep disruption, cardiovascular effects), and the fact that roughly 30% of children respond only partially or not at all. These medications tend to help with attention and behavior, but they do less to address emotional regulation or broader physical health, leaving some parents to seek other safe, complementary treatments.
Nutritional approaches, including omega-3 fatty acids, are one such avenue. Oily fish is the natural source, but clinical trials typically rely on supplements instead, since they allow for precise dosing, avoid the heavy-metal exposure that can come with high fish intake, and sidestep the problem of inconsistent dietary habits. Two omega-3s stand out as particularly relevant: DHA, which supports brain structure and cell-to-cell communication, and EPA, which helps reduce brain inflammation and improve blood flow. Both influence the dopamine and serotonin systems implicated in ADHD.
The Study:
Previous meta-analyses have generally found only modest overall benefits with mixed results. This mixed-results pattern may reflect the fact that children who had low omega-3 levels to begin with stand to benefit more than those whose levels are already adequate. This meta-analysis set out to test that idea directly, asking whether a child's baseline omega-3 status predicts how well they respond to supplementation.
To be included, studies had to be randomized controlled trials (RCTs) involving children diagnosed with ADHD who did not have major coexisting medical conditions. Trials that used broad multinutrient interventions, where the effect of omega-3s specifically couldn't be isolated, were excluded.
The resulting analysis of seven RCTs covering 654 children found small overall improvements in ADHD symptoms with omega-3 supplementation, consistent with earlier meta-analyses. There was little variation across studies, but a clear signal of publication bias, which the authors did not attempt to statistically correct for.
Among four RCTs involving 369 children with low baseline omega-3 levels, supplementation produced a moderate improvement in ADHD symptoms, with consistent results across studies. By contrast, the six RCTs covering 559 children with normal or high baseline omega-3 levels showed no improvement at all, again with consistent results across studies.
The Results:
The authors concluded: this systematic review and meta-analysis offers preliminary evidence that children’s response to long-chain omega-3 supplementation for ADHD may depend on their starting omega-3 nutritional status. Larger effects emerged in the subgroups defined by individual studies as having low baseline levels, while normal, high, or unstratified groups showed little evidence of benefit. In other words, there may be a benefit to children with ADHD taking omega-3 supplements, but only if they are already deficient.
Even still, a sensitivity analysis limited to ADHD symptom-rating scales found only a numerically higher effect in the low-baseline group. This means that these results, though positive, are not considered statistically significant.
The Take-Away:
Given that the evidence rests on just seven trials, that “low baseline” was defined differently across studies (using different biological markers and thresholds), and that several subgroup comparisons were not planned in advance, the authors caution that these findings should be treated as hypothesis-generating rather than conclusive.
The Background:
Previous research has suggested that people with ADHD have higher rates of death than those without the condition. Until now, many of those studies lacked the detail needed to untangle why this might be the case. A recent meta-analysis of eight separate studies reported that ADHD roughly doubled the risk of death, and it hinted that factors like socioeconomic status and other mental illnesses might help explain the link.
The Study:
To explore this in more detail, researchers used the US National Health Interview Survey, a nationally representative prospective cohort of just over 52,000 adults. Survey records were linked with the National Death Index, and participants were followed from the date of interview until death or December 31, 2019, whichever came first. The main outcome was death from any cause. With a median follow-up of just under eight years, there were 6,024 deaths recorded.
When the team adjusted their analysis for age, sex, ethnicity, and the year of the survey, having ADHD was associated with a 58% higher risk of death. Controlling further for family income and educational level reduced that increased risk slightly, to 50%.
Controlling for health conditions (like high blood pressure, diabetes, stroke, heart disease, and cancer) and lifestyle factors (smoking, alcohol use, physical activity, and body weight) also reduced the association to about 46%.
By contrast, when the researchers adjusted for two psychiatric conditions (anxiety and depression) commonly found alongside ADHD, the link between ADHD and higher mortality disappeared statistically. In other words, once anxiety and depression were taken into account, ADHD itself was no longer associated with a clearly measurable increase in the risk of death.
What Does This Mean?
The authors conclude that the apparent effect of ADHD on mortality seems to operate largely through accompanying mental illness, and to a lesser extent through lifestyle and physical health problems. They suggest that treating and managing these co-occurring issues (through medications, therapy, and behavioral interventions) might help reduce the risk of premature death in people with ADHD, although they note that further evidence is needed.
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