High Doses of Some ADHD Drugs Linked To Psychosis

3 min read

Sept. 12, 2024 – People taking some ADHD medications, such as Adderall, may face an increased risk of serious psychiatric issues like psychosis or mania, particularly when taking higher doses. 

ADHD medications work by increasing levels of brain chemicals called neurotransmitters, which help improve attention span, reduce hyperactivity, and manage impulsive behavior or issues with mental tasks like planning and organization. Though these medications are effective for many, doctors and patients should be aware of the potential mental health side effects, especially when the dosage is high. 

"Stimulant medications don’t have an upper dose limit on their labels, and dose is a factor in psychosis risk and should be a chief consideration when prescribing stimulants," said Lauren Moran, MD, a researcher who studies the use, benefits, and risks of drugs in large populations.

Moran’s team at McLean Hospital in Belmont, MA, did research that looked at emergency room admissions and found that patients prescribed amphetamines like Adderall had higher odds of having mania or psychosis within a month of using the medication. The findings were published Thursday in The American Journal of Psychiatry.

Psychosis refers to symptoms that mean a person has lost contact with reality, which can include suspiciousness and paranoid ideas, withdrawing socially and spending more time alone, a decline in self-care or hygiene, a hard time telling reality from fantasy, and confused speech. People with mania have over-the-top energy levels and a drastic change in mood or behavior, with symptoms that can include feeling invincible, minimal sleep, racing thoughts, fast speech, and false beliefs or perceptions.

The analysis included 1,374 people hospitalized for mania or psychosis, and 2,748 people hospitalized for other mental health conditions, most commonly depression, anxiety, or both. The hospitalizations happened between 2005 and 2019, and the people ranged in age from 16 to 35 years old. That age range was selected because it is typical for the start of psychosis or schizophrenia. The researchers were able to control for other potential influences, like substance use, they reported.

Psychiatric patients with a recent amphetamine prescription were more than two times as likely to be diagnosed with psychosis or mania, compared to those who didn’t use amphetamines. People who took a high dose had more than five times the risk.

The link between psychosis or mania and amphetamines had been established by prior research, but this latest study offers new details about how dosing may impact risk.

The highest risk, the researchers reported, was seen among people taking 30 milligrams or more of dextroamphetamine (the equivalent of 40 milligrams of Adderall).

There are two types of stimulant medications often prescribed for ADHD: amphetamine medications and methylphenidate medications. The researchers specifically noted that people prescribed the methylphenidate medications (sold under numerous brand names, including Ritalin and Concerta) were not linked to a heightened risk of psychosis or mania. The increased risks were limited to stimulants like Adderall and Vyvanse.

The researchers cautioned that their study has limits, including that their data only included hospitalized people and thus excluded people with less severe mental health conditions. Even so, they concluded that “the study results suggest that caution should be exercised when prescribing high doses of amphetamines, with regular screening for symptoms of psychosis or mania.”