News · Brain & Mental Health
Nearly twice as many autistic children with ADHD waited over a year to start medication
Guidance on treating ADHD in autistic children is thin and inconsistent. Across 24,117 Swedish young people with both conditions and 79,830 with ADHD alone, treatment started later, switched more, and no alternative beat the standard drug.
- Autistic children with ADHD waited longer to start medication than those with ADHD alone.
- Around one in seven waited more than a year after diagnosis, against one in thirteen.
- They also switched drugs more often and stopped sooner in the first three months.
- No alternative medication outperformed methylphenidate, the usual first choice.
- 104,000 Swedish young people in national registers, with nobody randomly assigned.
A child can be autistic and have attention deficit hyperactivity disorder, or ADHD, at the same time, and a great many are. What happens next depends on which diagnosis the clinic reaches for first.
Researchers writing in the British Medical Journal’s mental health title followed every young person in Sweden given an ADHD diagnosis over eleven years, and separated out the ones who were also autistic. Those with both conditions experienced longer delays to treatment initiation: roughly one in seven waited more than a year after diagnosis, against roughly one in thirteen of those with ADHD alone.
They then switched medicines more often, stopped sooner, and ended up no better off on any alternative than on the drug most of them should have been offered first.
The two diagnoses and the space between them
ADHD is a neurodevelopmental disorder involving trouble paying attention, trouble controlling impulsive behaviors, and being overly active to a degree that interferes with ordinary life.
Autism is a different developmental difference with its own profile, and the two overlap often. When they do, the clinical problem is not identifying either one. It is that clinical guidance on pharmacological treatment of ADHD in this clinical population remains limited and inconsistent, so what happens depends heavily on which clinician a family reaches.
That is the gap this study measured, using a country that keeps records good enough to measure it.
What Swedish registers could see
Every child diagnosed with ADHD between 2007 and 2018 was followed to 2021: 24,117 who were also autistic, 79,830 who were not.
Because prescriptions, hospital admissions, injuries and specialist visits are all recorded nationally and linked, the analysis could watch what was prescribed, when, what came next, and what happened around it. No survey depends on anyone remembering.
The headline comparison is simple arithmetic on timing. Among children and adolescents with both conditions, 12-14% initiated more than 12 months after diagnosis. Among those with ADHD alone, 7-8% did.
The churn after treatment starts
Delay was not the only difference. Children with ADHD and autism were slightly more likely to discontinue treatment within 3 months, 16% against 12%, and they had the highest average number of medication switches within 3 years, averaging 2.6.
Two and a half medication changes in three years is a lot of disruption for a child who finds change difficult, and it points at something the delay figure alone does not: clinicians treating this group are less certain, and that uncertainty shows up as churn.
The comparison that came out flat
If all that switching were finding something, you would expect the destination drugs to outperform the starting one. They did not.
The team compared alternative ADHD medications against methylphenidate, the stimulant used first for most people, and looked at what happened to hard outcomes in the year after starting compared with the year before: psychiatric admissions, accidental injuries, and specialist visits for substance use, depression or anxiety.
Comparisons of alternative ADHD medications versus methylphenidate turned up nothing, after correcting for multiple comparisons. The effects of alternative ADHD medication options on key negative clinical outcomes appeared similar to those of methylphenidate.
A null result here is genuinely informative rather than a failure. It says the switching is not being rewarded, and that a clinician hesitating over whether the usual first choice is wrong for an autistic child does not have evidence that something else would be better.
What the study cannot tell you
It did not test whether the delay does harm. That would need a comparison between children who waited and children who did not, holding everything else constant, and this design does not provide it. The wait is documented; its cost is not.
Nor can it explain the delay. Diagnostic overshadowing, where a new problem gets folded into a diagnosis already on the file, is the usual suspicion, and it is a suspicion rather than a finding here.
And these are Swedish registers. A country with universal healthcare and near-complete record linkage is the best place to measure this and not necessarily a guide to how long the wait is somewhere with insurance barriers and thinner services.
What follows from it
The authors do not conclude that a particular drug should be moved up the list. They conclude the opposite, that fixed rules are the wrong instrument here.
Rather than recommending fixed first-line and second-line treatments, they argue, guidelines should push for training and for treatment started promptly and based on a shared decision-making process with the family.
The word doing the work in that sentence is prompt. On the evidence here, the drug chosen mattered less than how long a child waited before anyone chose one, and that is a fixable problem in a way that pharmacology is not.
People also ask
What did the study find?
Individuals with ADHD and autism experienced longer delays to treatment initiation, with 12-14% starting more than 12 months after diagnosis versus 7-8% in those with ADHD alone. Children with both were slightly more likely to discontinue within 3 months (16% vs 12%) and had the highest average number of medication switches within 3 years (2.6).
Did any medication work better than the standard one?
No. In within-individual analyses, comparisons of alternative ADHD medications versus methylphenidate did not yield statistically significant differences after correcting for multiple comparisons. The alternatives were neither better nor worse on the outcomes measured.
What is methylphenidate?
The stimulant most commonly used first for ADHD, sold under brand names including Ritalin and Concerta. Alternatives include other stimulants such as amphetamines, and non-stimulants such as atomoxetine and guanfacine.
What outcomes were measured?
Changes in rates of psychiatric hospital admissions, accidental injuries, and specialist visits for substance use, depression or anxiety, in the year after starting medication compared with the year before. These are hard events recorded in national registers rather than symptom questionnaires.
Why would treatment be delayed for autistic children?
The study describes the pattern rather than explaining it. Plausible contributors include diagnostic overshadowing, where new symptoms get attributed to the autism already on file, thinner and less consistent clinical guidance for this group, and more caution among prescribers about side effects.
Is a delay harmful?
This study did not test that directly. It measured what happened around medication starting, not what the wait itself cost. What it establishes is that the delay is real and systematic rather than anecdotal.
What do the authors recommend?
That guidelines stop trying to name fixed first-line and second-line drugs for this group and instead emphasize appropriate training as well as prompt, individualized treatment based on shared decision-making. This is general information rather than medical advice.