When Lauren Moran, M.D., started working as an inpatient psychiatrist at McClean Hospital in Boston, she noticed a surprising amount of college students getting admitted for psychosis or mania who had no history of psychiatric symptoms. Many did, however, have a recent prescription for Adderall (a type of amphetamine) to treat symptoms of Attention Deficit/Hyperactivity Disorder (ADHD). “This is a known side effect. The FDA put it on their labels,” says Dr. Moran. “But there hadn’t been a lot of research about it.”
Amphetamines like Adderall and Vyvanse are central nervous system stimulants, which help increase levels of certain chemicals in the brain associated with attention, energy, and alertness.
Her work at McClean Hospital piquing her interest around amphetamines and the risk of psychosis, Dr. Moran published a study in 2019 showing that in individuals with ADHD, amphetamines were associated with a greater risk of psychosis than methylphenidates, which are another common type of drug prescribed for ADHD.
Following that research, Dr. Moran went deeper into the amphetamine rabbit hole, publishing her new study on September 12, 2024, which shows the risk of psychosis from amphetamines rises dramatically at higher doses of the drug
“[Dr. Moran’s] study was very reasonable and was statistically sound,” says Lawrence Diller M.D., a pediatrician in California specializing in development and behavior. “But to an old pro like me who’s been around 40 plus years, this information is not really new.”
Dr. Moran emphasized that the study does not suggest that all amphetamine prescriptions are dangerous, as this particular side effect is rare. In fact, “if you’re on a low dose, for example, there’s really not much of a risk,” she says. But doctors and patients need to “be careful about using these high doses.”
Amphetamines: More Popular In the U.S. Than Other ADHD Medications
Amphetamines are a class of stimulants commonly prescribed in the U.S. to treat ADHD. While stimulants like amphetamines and methylphenidates are usually the first-line medications for treating the symptoms of ADHD, there are non-stimulant medications available as well.
Interestingly, most countries favor methylphenidate drugs (like Ritalin and Concerta) over amphetamines as the first line of defense in treating ADHD —except for the U.S. In the United States, amphetamines are more the commonly prescribed drugs.
“The U.S. is the only country that predominantly uses amphetamines,” says Dr. Moran. “And I really don’t know why. It could be due to pharmaceutical advertising, or it could just be due to cultural factors.”
Drugs derived from amphetamine include:
- Adderall
- Evekeo
- proCentra
- Zenzedi
- Adzenys
- Dexedrine Spansule
- Dyanavel
- Mydayis
- Vyvanse
- Guanfacine/Intuniv
- Clonidine/Kapvay
- Atomoxetine/Straterra
- Viloxazine/Qelbree
Amphetamines and Psychosis: What The 2024 Study Uncovers
For her 2024 study, Dr. Moran and her team reviewed the medical records of 4,122 patients between the ages of 16 and 35 who had been hospitalized at McLean Hospital for a psychiatric condition. Of those patients, 1374 were hospitalized for psychosis or mania; the others, who were hospitalized for anxiety or depressive symptoms, were considered the control group.
The patients who experienced psychosis were more than twice as likely as their counterparts to have had a prescription for amphetamines in the last 30 days. The risk was mostly seen among patients who had been taking the highest doses of amphetamines. The odds of psychosis were raised more than five-fold among patients who were prescribed more than 30mg of dextroamphetamine (ProCentra, Zenzedi, Dexedrine Spansule), 40mg of mixed amphetamine salts (Adderall, Mydayis) or 100mg of lisdexamfetamine (Vyvanse).
Because the current study occurred within a single hospital, Dr. Moran says the next step is replicating the findings in a larger national population.
“Overall, I think the study is timely given the huge amount of legal and illegal prescription stimulant use in America,” says Dr. Diller. “It will remind both physicians and their patients that going much above 30 mg daily is both unlikely to further ameliorate ADHD symptoms and significantly increases the slight chance of a psychotic episode.”
When it comes to people’s desire to find relief using amphetamines (and possibly using higher dosages to find that relief), Dr. Moran notes that “sometimes, I find that people expect that they should have no symptoms of ADHD. This drug is not going to get rid of your ADHD,” Dr. Moran continues. “It’s just going to make things a little more manageable. Managing expectations is important.”
