People with ADHD and substance dependence rarely respond as they should to ADHD medication. A randomised study from Karolinska Institutet now shows that it is possible to obtain the desired efficacy by administering the drug in higher doses. The results of the study are published in the scientific journal Addiction.
ADHD is much more common in people who use drugs than in the population at large. ADHD can be treated with methylphenidate, a CNS stimulant used for both children and adults. However, no previous studies have been able to show that methylphenidate is effective against ADHD in people with dependence. One possible reason for this lack of potency is that the doses tested were too low to have an effect on people with ADHD and long-standing substance dependence, since such individuals have often developed a tolerance to CNS stimulants.
In this latest study, researchers examined the effect of the medication on prison inmates with ADHD and amphetamine dependenc, using doses up to double those administered in previous studies. What they found was that the experimental group had fewer relapses into drug use, displayed fewer ADHD symptoms and adhered to their treatment regimens for longer than the placebo group.
"We've shown for the first time that ADHD in these patients is treatable," says lead-author Dr Maija Konstenius at the Department of Clinical Neuroscience. "Moreover, the treatment led to fewer relapses to drug use, which is a very significant finding since a return to crime is often linked to drug abuse in this group."
The present study was a randomised placebo-controlled clinical trial involving 54 incarcerated men diagnosed with ADHD and with amphetamine dependence. The participants were randomly assigned to either of two groups, one that received methylphenidate (Concerta) and one that received an identical placebo (inactive pill) for a total of 24 weeks. The participants began their treatment two weeks before their release from prison and then continued it during non-custodial care. They also received psychological therapy to help them handle the risk of relapsing into drug use.
The study was conducted in partnership with the Stockholm County Council and the Swedish Prison and Probation Service and was financed by grants from the Swedish Research Council and other bodies.