Often prescribed to treat attention-deficit/hyperactivity disorder, the risk was highest in those taking 30 mg or more of dextroamphetamine (which corresponds to 40 mg of Adderall),

The researchers identified 1,374 cases of individuals presenting with first-episode psychosis or mania, compared to 2,748 control patients with a psychiatric hospitalization for other conditions like depression or anxiety. They conducted a comparison analysis of stimulant use over the preceding month and accounted for other factors, including substance use, in order to isolate the effects of stimulants.

They found the attributable risk percentage among those exposed to any prescription amphetamine was nearly 63 percent and for high dose amphetamine was 81 percent. These findings suggest that among people who take prescription amphetamine, 81 percent of cases of psychosis or mania could have been eliminated if they were not on the high dose. While a significant dose-related risk increase was seen in patients taking high doses of amphetamine, no significant risk increase was seen with methylphenidate (Ritalin) use, which is consistent with previous research, including a 2019 study led by Moran.

https://news.harvard.edu/gazette/story/2024/09/high-doses-of...

Among 1,374 case subjects and 2,748 control subjects, the odds of psychosis and mania were increased for individuals with past-month prescription amphetamine use compared with no use (adjusted odds ratio=2.68, 95% CI=1.90–3.77). A dose-response relationship was observed; high doses of amphetamines (>30 mg dextroamphetamine equivalents) were associated with 5.28-fold increased odds of psychosis or mania

https://psychiatryonline.org/doi/10.1176/appi.ajp.20230329

I don't care, the drug isn't safe. I've seen it permanently change many people. I don't care if they handpicked <100 individuals to prove safety. The doses cited above >40mg are pretty typical.