Attention deficit hyperactivity disorder (ADHD) comprises a range of behavioural problems including inattention, hyperactivity and impulsivity. Diagnosis and treatment of the disorder is made difficult due to its unknown biological basis.

Several studies have identified abnormalities in membrane fatty acids in some subjects with ADHD, and some success has been reported using lipid therapies.

We have measured exhalant ethane levels, a non-invasive measure of oxidative damage to n-3 fatty acids, to probe biochemical alterations in ADHD.

Patients with ADHD (N = 10) had higher levels of ethane in exhalant than in healthy volunteers (N = 12) with approximately 50% of ADHD cases being above the control range. In contrast, levels of butane, a marker of protein oxidation, were unaltered.

Our data, although preliminary, suggests that some patients with ADHD have higher rates of oxidative breakdown of n-3 polyunsaturated fatty acids (PUFAs).

Such a biochemical abnormality may underlie the previously observed fatty acid deficiencies, as well as providing further rationale for the use of anti-oxidant and/or lipid supplementation therapy in the treatment of ADHD. Larger studies of ADHD using this non-invasive assessment of oxidative stress appear warranted.