De gevolgen van ADHD medicijnen*
Uit een studie blijkt dat medicijnen die gebruikt worden bij ADHD ongewenste hallucinaties teweeg brengen bij jongeren. Uit een andere studie, weliswaar met muizen blijkt dat de vaak gebruikte medicijnen Ritalin en Concerta duidelijke veranderingen in de hersenen teweeg
brengen. De eerste studie is een analyse van 49 trials over het gebruik van verschillende ADHD medicijnen waaronder Ritalin en Concerta. Hieruit blijkt dat bij het gebruik bij kinderen vaak leidt tot vreemde hallucinaties, meestal over slangen en insecten die over hen heen kruipen. In de tweede studie blijkt dat de stof methylfenidaat in Ritalin en Concerta neuronen in de hersenen kunnen veranderen. Omdat zowel methylfenidaat als cocaïne een psychostimulantium zijn kregen de muizen of een injectie met methylfenidaat of cocaïne en werd en de hersenen bekeken op de gevolgen. Methylfenidaat was werkzaam in bepaalde delen van de hersenen, cocaïne in andere gedeelten, er waren overlappingen en in sommige gedeelte waren de effecten van methylfenidaat duidelijk groter dan cocaïne. Deze studie geeft aan dat meer onderzoek nodig is naar de effecten van methylfenidaat op de
hersenen, ook op langere termijn.
Hallucinations and Other Psychotic Symptoms Associated With the Use of Attention-Deficit/Hyperactivity Disorder Drugs in Children
Andrew D. Mosholder, MD, MPHa, Kate Gelperin, MD, MPHa, Tarek A. Hammad, MD, PhD, MSc, MSa, Kathleen Phelan, RPha and Rosemary Johann-Liang, MDb
a Office of Surveillance and Epidemiology, Center for Drug Evaluation and Research, US Food and Drug Administration, Silver Spring, Maryland
b Health Resources and Services Administration, Department of Health and Human Services, Rockville, Maryland
OBJECTIVES. To gain a better understanding of the capacity of psychostimulant medications to induce adverse psychiatric reactions and determine the frequency of such reactions, we analyzed postmarketing surveillance data and clinical trial data for drugs, either approved or under development, for the treatment of attention-deficit/hyperactivity disorder.
METHODS. The US Food and Drug Administration requested manufacturers of drugs approved for attention-deficit/hyperactivity disorder or with active clinical development programs for that indication to search their electronic clinical trial databases for cases of psychosis or mania using prespecified search terms. The manufacturers supplied descriptions of clinical trials, numbers of patients exposed to study drug, and duration of exposure to permit calculations of incidence rates. Independently, cases of psychosis or mania in children and adults for drugs used to treat attention-deficit/hyperactivity disorder from the Food and Drug Administration Adverse Event Reporting System safety database were analyzed. Manufacturers were asked to conduct similar analyses of their postmarketing surveillance databases.
RESULTS. We analyzed data from 49 randomized, controlled clinical trials in the pediatric development programs for these products. A total of 11 psychosis/mania adverse events occurred during 743 person-years of double-blind treatment with these drugs, and no comparable adverse events occurred in a total of 420 person-years of placebo exposure in the same trials. The rate per 100 person-years in the pooled active drug group was 1.48. The analysis of spontaneous postmarketing reports yielded >800 reports of adverse events related to psychosis or mania. In 90% of the cases, there was no reported history of a similar psychiatric condition. Hallucinations involving visual and/or tactile sensations of insects, snakes, or worms were common in cases in children.
CONCLUSIONS. Patients and physicians should be aware that psychosis or mania arising during drug treatment of attention-deficit/hyperactivity disorder may represent adverse drug reactions.
NIDA Study Shows That Methylphenidate (Ritalin) Causes Neuronal Changes In Brain Reward Areas
Investigators funded by the National Institute on Drug Abuse (NIDA) have shown that the medication methylphenidate (Ritalin), which is commonly prescribed to treat attention-deficit hyperactivity disorder (ADHD), can cause physical changes in neurons in reward regions of mouse brains; in some cases, these effects overlapped with those of cocaine. Both methylphenidate and cocaine are in the class of drugs known as psychostimulants. While methylphenidate is widely prescribed, this study highlights the need for more research into its long-term effects on the brain. These research findings will be published in Proceedings of the National Academy of
Sciences.
"Studies to date suggest that prescribed use of methylphenidate in patients with ADHD does not increase their risk for subsequent addiction. However, nonmedical use of methylphenidate and other stimulant medications can lead to addiction as well as a variety of other health consequences," said NIDA Director Dr. Nora Volkow. "This study highlights the fact that we know very little about how methylphenidate affects the structure of and communication between brain
cells."
The researchers exposed mice to 2 weeks of daily injections of cocaine or methylphenidate, after which reward areas of the brain were examined for changes in dendritic spine formation, which is related to the formation of synapses and the communication between nerve cells; and the expression of a protein, delta Fos B, which has been implicated in the long-term actions of addictive drugs. Both drugs increased dendritic spine formation and the expression of delta Fos B; however, the precise pattern of their effects was distinct. It differed in the types of spinesaffected, the cells that were affected, and the brain regions. In some cases, there was overlap between the two drugs; further, in some cases, methylphenidate produced greater effects than cocaine-for example, on protein expression in certain regions.
"Methylphenidate, which is thought to be a fairly innocuous compound, can have structural and biochemical effects in some regions of the brain that can be even greater than those of cocaine," stated Dr. Yong Kim, lead author of the study. "Further studies are needed to determine the behavioral implications of these changes and to understand the mechanisms by which these drugs affect synapse formation," he added.
Previous studies, including two that were reported by NIDA on April 1, 2008 ("NIH Research Suggests Stimulant Treatment for ADHD Does Not Contribute to Substance Abuse Later in Life"), have shown that children treated with stimulants for ADHD early in life have no greater risk of drug addiction as
adults.
The National Institute on Drug Abuse is a component of the National Institutes of Health, U.S. Department of Health and Human Services. NIDA supports most of the world's research on the health aspects of drug abuse and addiction. The Institute carries out a large variety of programs to inform policy and improve practice. Fact sheets on the health effects of drugs of abuse and information on NIDA research and other activities can be found on the NIDA home page at
http://www.drugabuse.gov.
The National Institutes of Health (NIH) - The Nation's Medical Research Agency - includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary Federal agency for conducting and supporting basic, clinical, and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases.
National Institutes of Health (April
2009)
