The study, conducted by researchers at McLean Hospital and Harvard Medical School, looked at teens and young people who had recently begun taking two classes of drugs - amphetamines (marketed as Adderall and Vyvanse) and methylphenidates (marketed as Ritalin or Concerta) - used to treat ADHD.
The study showed that while the chance of developing psychosis - a condition that affects the mind and causes a person to lose contact with reality - is low, there is an increased risk of developing the disorder in patients taking the amphetamines.
"The findings are concerning because the use of amphetamines in adolescents and young adults has more than tripled in recent years. More and more patients are being treated with these medications," said Dr. Lauren V. Moran, lead author of the paper.
"There is not a lot of research comparing the safety profiles of amphetamines and methylphenidate, despite increasing use of these medications," Moran said.
Moran said that clinicians have long observed "patients without previous psychiatric history" developing psychosis "in the setting of stimulant use."
The study, which was funded by the National Institutes of Health, looked at insurance claims on more than 220,000 ADHD patients between the ages of 13 and 25 years old who had started taking amphetamines or methylphenidate between Jan. 1, 2004, and Sept. 30, 2015.
According to the study, researchers found that one out of every 486 patients started on an amphetamine developed psychosis that required treatment with antipsychotic medication. One in 1,046 patients started on methylphenidate developed psychosis.
The study showed that the development of psychosis appeared in people who had recently begun taking the amphetamines.
Moran stressed that "people who have been on a drug like Adderall for a long time, who are taking the drug as prescribed and are tolerating it well, are not likely to experience this problem (psychosis)."
The paper, "Psychosis with Amphetamine or Methylphenidate in Attention Deficit Disorder," is set to be published on Thursday in the New England Journal of Medicine.
ADHD Attention deficit hyperactivity disorder (ADHD) affects children and teens and can continue into adulthood. ADHD is the most commonly diagnosed mental disorder of children. Children with ADHD may be hyperactive and unable control their impulses. Or they may have trouble paying attention. These behaviors interfere with school and home life.
It's more common in boys than in girls. It's usually discovered during the early school years, when a child begins to have problems paying attention.
Adults with ADHD may have trouble managing time, being organized, setting goals, and holding down a job. They may also have problems with relationships, self-esteem, and addiction.
