An analysis of previous studies of children and young adults with Attention-Deficit/Hyperactivity Disorder (ADHD) has quantified the extent to which stimulant treatment reduces the development of mood disorders, problems in school, conduct disorder, substance use disorders, and other issues associated with the condition.

The study, led by investigators at Massachusetts General Hospital, is the first to quantify the effects of stimulant treatments, and it found strong protective effects against the development of serious ADHD-associated functional complications.1

Data have shown that about 27% of children and 45-50% of adolescents have conduct disorder, which is characterized by aggression, destruction of property, and other behavioral problems. Approximately 38% of adults with ADHD also have a co-occurring mood disorder, including depression, mania, and bipolar disorder.2

Stimulant medications, including mixed salts of a single-entity amphetamine product (Adderall, Takeda), methylphenidate (Ritalin, Novartis), and others, are the most commonly used treatments for ADHD, and may prevent development of other co-existing concerns.

The investigators analyzed data from 3 previously published studies. They calculated the number needed to treat (NNT) statistic, which reflects the number of individuals receiving a medication or other treatment needed to prevent a specific unwanted outcome—the lower the NNT, the more effective the treatment. 

Two of the studies were long-term, prospective studies of children with and without ADHD, some treated with stimulants and some not. The third study was a randomized, double blind study of young adults with ADHD that compared their performance on a driving simulation upon entering the study and after six weeks of treatment with either a placebo or a stimulant.

The NNTs for the outcomes of interest were low:
  • Three participants with ADHD required treatment to prevent them from repeating a grade or developing conduct disorder, anxiety disorders, or oppositional-defiant disorder.
  • Four participants with ADHD needed treatment to prevent them from developing major depression or experiencing an accident during the driving simulation.
  • Five participants with ADHD required treatment to prevent them from developing bipolar disorder, six to prevent them from smoking cigarettes, and ten to prevent them from developing a substance use disorder.1
When adjusting for the sex of participants or other factors, the only change was that the protection against substance use disorders was stronger in younger participants.

"Now we have the evidence allowing us to say that stimulant treatment of ADHD prevents the development of several very serious functional outcomes," said Joseph Biederman, MD, chief of the Pediatric Psychopharmacology and Adult ADHD Program at Massachusetts General Hospital and MassGeneral Hospital for Children, in a prepared statement. "However, the impact on other serious outcomes—such as post-traumatic stress disorder, traumatic brain injury, suicide risk and employment success—still needs to be investigated."

  1. Biederman J, Disalvo M, Fried R, et al. Quantifying the Protective Effects of Stimulants on Functional Outcomes in Attention-Deficit/Hyperactivity Disorder: A Focus on Number Needed to Treat Statistic and Sex Effects. Journal of Adolescent Health. July 2019. doi:10.1016/j.jadohealth.2019.06.015.
  2. Children and Adults with Attention-Deficit/Hyperactivity Disorder (CHADD). Coexisting Conditions. CHADD website. Accessed August 5, 2019.