Amphetamines for attention deficit hyperactivity disorder (ADHD) in adults
Most amphetamine trials in adults lasted only a few weeks — how will we judge whether Adderall is still helping me months from now?
Well-supported by good-quality research. how we score evidence
Caveat on this rating: 16 of the 19 included trials were industry-funded and the review graded the evidence low to very low quality, so effect sizes may be optimistic.
Pooling 19 randomized trials with 2,521 adults, amphetamines reduced clinician-rated ADHD symptom severity (SMD -0.90) over an average of about 5 weeks, including mixed amphetamine salts (SMD -0.80), but nearly tripled withdrawals due to adverse events and showed no evidence of better treatment retention.
Worth asking
Most amphetamine trials in adults lasted only a few weeks — how will we judge whether Adderall is still helping me months from now?
What it is FDA approved for
Read off the label. Trial duration and approval year are shown only where they were recorded — never inferred.
- Attention-deficit/hyperactivity disorder (ADHD)
- Narcolepsy
Source
Amphetamines for attention deficit hyperactivity disorder (ADHD) in adults — Castells X, et al. (2018)
Top-tier peer-reviewed journal
Read the source: https://doi.org/10.1002/14651858.CD007813.pub3
DOI: 10.1002/14651858.CD007813.pub3
How this was scored
- Study design
- Meta-analysis of randomised trials
- Funding
- Funding not disclosed
- Published in
- Top-tier peer-reviewed journal
- Sample size
- 2,521
- Preregistered
- Yes
- Conflicts disclosed
- Yes
- Independent of proponent
- not recorded
- Retracted
- No
Read the full scoring rubric, including what it can't tell you.
Published August 19, 2026.
Where we put this study in context
Questions
How strong is the evidence behind this?
Resolv rates this source "strong evidence". Well-supported by good-quality research. It scores 81 out of 100 on our published rubric. One caveat travels with that badge: 16 of the 19 included trials were industry-funded and the review graded the evidence low to very low quality, so effect sizes may be optimistic. The score is calculated from recorded facts about the source — study design, funding, publication venue, sample size, preregistration — not typed in by an editor.
What is the source for this?
Amphetamines for attention deficit hyperactivity disorder (ADHD) in adults — Castells X, et al. (2018). Published in: Top-tier peer-reviewed journal. DOI: 10.1002/14651858.CD007813.pub3. The full source is linked on this page so you can read it yourself.
Who paid for this research, and does that matter?
Study design: Meta-analysis of randomised trials. Funding: Funding not disclosed. Independence from the proponent is not recorded. Industry sponsorship is one of the most reliably measured biases in medicine, which is why funding carries real weight in the score rather than sitting in a footnote.
Is amphetamine (Adderall, Mydayis, Evekeo), adderall, mydayis, evekeo FDA approved?
Yes — FDA approved for Attention-deficit/hyperactivity disorder (ADHD), Narcolepsy. Approval is for a specific indication, not for everything the drug is prescribed for.
Is this medical advice?
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.
This is information to bring to your prescriber, not medical advice and not a reason to change anything on your own. Nothing here is an instruction to stop or reduce a medication. If you are in crisis, call or text 988.