For many children, treating ADHD with stimulant medications, such as Ritalin or Adderall, is part of the daily routine. These medications are effective at increasing attention and decreasing hyperactivity and impulsive behaviors. As much as many parents rely on these medications for their children, there are also questions and concerns surrounding the medications. For some, delayed growth and not gaining weight is a problem. Other side effects, such as nervousness or anxiety cause difficulties for some children. But regardless of whether there are side effects, many parents worry about the long-term effects of taking these medications.
ADHD is a lifelong condition. While it was once considered a "childhood disorder," it is now known that symptoms of ADHD often continue into adulthood, causing problems at work and in relationships. According to the National Institute of Mental Health, 4.1 percent of the adult population in the United States has ADHD, with over 40 percent of those diagnosed considered "severe" ADHD. This means that children who take stimulant medications to help with symptoms of ADHD could continue taking the medication for many years.
And the question that plagues many parents and adults with ADHD: is it safe to take this medication long-term?
Recent studies have looked at just this question. One study, completed at Wake Forest Baptist Medical Center and published online in the journal Neuropsychopharmacology, showed that the medication had no long-term effect on the development of the brain. The researchers used primates, with ages equivalent to 6 to 10 year old children. Half of the primates were given methylphenidate (Ritalin) for one year, which would be equivalent to four human years.
At the end of the study, scientists found "no long-lasting effects on the neurochemistry of the brain, no changes in the structure of the developing brain." 
Another concern is that using stimulant medications can lead to later substance abuse. The same study looked at this and found no higher risk. The primates in the study, after stopping medication, were able to self administer cocaine for several months. Researchers noted how much of the drugs the primates took, how quickly they took them and how susceptible they were to the drugs. The primates who had taken stimulant medication were no more susceptible to drug use than those who did not take the medication.
There has been much controversy over ADHD medications but for many, this type of treatment helps in many ways. Dr. Charles Raison, in an article on CNN.com, states, "ADHD is a serious disorder that has long-term negative consequences on a person's life. In general, treatment provides long-term benefit, but it's not perfect, and most children with ADHD continue to struggle into their teen years, compared to their peers without ADHD. If you can find an intervention - either medication-based or therapy-based-that produces significant improvements, this is a strong sign that your child will probably do well over the long term, especially if he or she continues with the treatment." 
But medication affects each person differently and the benefits of taking medication must be weighed against any side effects or possible long term problems. Many doctors require regular evaluations, sometimes as frequent as every 6 months, to check for growth, neurological development and blood pressure while taking ADHD medications, that way any concerns over possible health related issues from long-term use can be monitored and discussed as issues arise.
"Attention-Deficit/Hyperactivity Disorder Among Adults," Date Unknown, Staff Writer, National Institute of Mental Health
"Chronic Treatment with Extended Release Methylphenidate Does Not Alter Dopamine Systems or Increase Vulnerability for Cocain Self-Administration: A Study in Nonhuman Primates," 2012, November, Kathryn E. Gill et al, Neuropsychopharmacology
 "Long-Term ADHD Durg Use Is Not Harmful, 2012, July 20, Staff Writer, Medical News Today
"Long-term Exposure to Oral Methylphenidate or dl-Amphetamine Mixture in Peri-Adolescent Rhesus Monkeys: Effects on Physiology, Behavior, and Dopamine System Development," 2012, November, Paul L. Soto et al, Neuropsychopharmacology
 "What Are the Long-Term Effects of ADHD Meds?" 2010, January 19, Dr. Charles Raison, CNNHealth.com