Modafinil and IQ: what the studies found, and where the post went wrong

**Research review** ## What is known, what is not, and the risks Modafinil is a prescription wakefulness medicine, and the rules for supplying it differ by country. This article offers no guidance on dosing, timing or where to get it. - **Known:** in a 2005 study (S-001), gains on an attention task showed up in people with lower baseline IQ, not in those with higher IQ. A 2020 meta-analysis (S-003) found the overall effect on cognitive tasks to be small. - **Unknown:** long-term safety, and whether there is any benefit for people who are not sleep-deprived. For the two 2005 studies we have only the abstracts, not the full texts. - **Risks:** in a seven-year series of ground tests on Singapore military aviators (S-004), some people reported headache, anxiety, diarrhoea or insomnia. These are retrospective records, not a controlled safety trial. Do not start or change use without a doctor, particularly with heart or mental-health conditions, sleep problems, or other medicines. ## The hook "Modafinil makes you smarter" is easy to repeat and easy to forward. Here is what the data actually show, and which parts of the original post the studies do not support. ## In brief - A 2005 study (Randall, Shneerson, File) of 89 students found improved attention scores only in the group with lower baseline IQ. IQ was not measured as an outcome [S-001]. - A second 2005 study of 60 healthy students found mixed results: a few tests improved slightly, others did not. The authors do not consider the drug a cognitive enhancer for people who are not sleep-deprived [S-002]. - A 2020 meta-analysis of 14 modafinil studies in healthy, non-sleep-deprived adults reported an overall effect of SMD 0.12 and an effect on memory updating of SMD 0.28. The authors describe the effects as small and say the data do not support the idea that the drug is an effective enhancer [S-003]. ## What the studies measured The first 2005 paper pooled two earlier experiments on healthy university students. Participants were split by baseline IQ and compared with placebo. Scores on a sustained-attention test improved in the lower-IQ group (mean IQ 106) but not in the higher-IQ group (mean 115.5) [S-001]. This is a retrospective analysis of subgroups. A finding like this is a reason to test again, not proof that the drug raises intelligence. The second paper was a randomised, double-blind study of 60 students. The drug helped a few measures, such as colour naming speed, sustained attention and digit span, and did nothing for others. The authors saw no clear dose-related pattern and concluded that the benefits were too limited to call modafinil a cognitive enhancer in people who are not sleep-deprived [S-002]. The Singapore series (S-004) tested 243 military aircrew on the ground over seven years. 237 people (97.5%) were cleared for operational use, and six did not pass. Headache occurred in 1.65%; anxiety, diarrhoea and insomnia in 0.41% each. The authors report no major adverse drug events. The group was almost entirely young men of Asian ethnicity, so these figures cannot be assumed for everyone. ## Where the post overreached - **"It raises IQ."** IQ was not measured as an outcome. Groups were defined by baseline IQ, and the results were scores on attention and speed tasks. - **"It will improve intelligence in 75–85% of people."** That is arithmetic built on a normal distribution, not a result from any study. Removed. - **"Potential to treat Alzheimer's."** A treatment claim with no support in the material. Removed. - **"The famous smart pill, on a budget."** A metaphor, not data. Removed. - **Advice to find an "individually chosen dose".** That is dosing guidance. Removed; this article gives no doses. ## What comes next If your question is about sleep, alertness or night shifts, discuss it with a doctor. The cause of tiredness and your health matter more than which product you choose. This article does not compare modafinil with other options. ## A question for readers For you, what matters more in a study: the average result for a group, or how a drug works for one particular person? ## What was checked and what was meant | Claim | Status | Source | |---|---|---| | 2005 study: attention gains only in participants with lower baseline IQ (106 vs 115.5) | checked against the PubMed abstract (Pharmacol Biochem Behav 82:133–139); full text not opened | S-001 | | 2005 study: IQ was not measured as an outcome | checked against the abstract; subgroup finding | S-001 | | Second 2005 study (60 students): mixed effects, no clear dose pattern | checked against the PubMed abstract (J Clin Psychopharmacol 25:175–179); full text not opened | S-002 | | Authors' conclusion: insufficient to call it a cognitive enhancer in non-sleep-deprived people | checked against the abstract | S-002 | | 2020 meta-analysis: overall effect SMD 0.12; memory updating SMD 0.28; effects small | checked against the PubMed abstract (Eur Neuropsychopharmacol 38:40–62) | S-003 | | Singapore series of 243 aircrew: 237 cleared; headache 1.65%; anxiety, diarrhoea, insomnia 0.41% each; no major events | checked against the PubMed abstract (Aerosp Med Hum Perform 90:480–483); retrospective series | S-004 | | Modafinil raises IQ | not supported: IQ was not measured as an outcome; corrected from the post | S-001 | | Modafinil will improve intelligence in 75–85% of people | not supported; arithmetic from the post, removed | — | | Potential to treat Alzheimer's | not supported; treatment claim, removed | — | | "The famous smart pill, on a budget" | opinion from the post, removed | — | | Author's personal experience | not provided in the materials; no block added | — | Author: Serge Luboff. Reviewer: not assigned. Medical review: not carried out. This is not medical advice and does not replace a consultation with a doctor.