As attention deficit hyperactivity disorder (ADHD) affects around 1 in every 25 school-aged children, managing this condition is of huge social importance. An article published in BMC Psychiatry this week shows that zinc supplements could increase the effectiveness of stimulants used to treat children with the disease.

The effects of ADHD on individual children differ, but symptoms include inattention, hyperactivity and impulsiveness. Stimulants are the most common treatment prescribed, but recent findings that vitamin and mineral deficiencies correlate with ADHD suggest that dietary supplements could also play a role in disease management.

Researchers from Iran carried out a controlled trial to assess the benefits of prescribing supplementary zinc alongside the more conventional methylphenidate treatment. They found that children taking additional zinc sulphate on a daily basis improved faster than those taking a placebo.

The study comprised 44 children who were diagnosed as suffering from ADHD at Roozbeh Psychiatric Hospital, Tehran. Prior to the trial none of these patients had taken any medication for their condition.

For the six weeks of the trial, half the children took zinc sulphate (55mg/day) in addition to the conventional treatment; the other half took a placebo. A child psychiatrist assessed the children's condition fortnightly.

The behaviour of both groups of children improved over the course of the trial, but the children taking the zinc supplements showed a more marked improvement in their condition after six weeks, compared with those taking the placebo.
Zinc supplements may exert their positive effects by helping to regulate the function of the neurotransmitter dopamine. Dopamine signalling, which has been implicated in causing symptoms of ADHD, is believed to play an important role in the feelings of pleasure and reward.

The authors acknowledge that their study is only small. They suggest that further research in this area is needed to confirm the positive effects of zinc supplements on children with ADHD.