Saturday, 1 August 2015

Methylphenidate: a repairer of the 'oxidative balance' in ADHD?

A fairly quick post for you today based on the findings reported by Esra Guney and colleagues [1] who examined whether markers of oxidative stress - an imbalance "between the systemic manifestation of reactive oxygen species and a biological system's ability to readily detoxify the reactive intermediates or to repair the resulting damage" - might be something to look at when it comes to cases of attention-deficit hyperactivity disorder (ADHD).

They concluded that, based on a small-ish sample size, there may be more to see when it comes to oxidative metabolism with ADHD in mind. Their findings are not a million miles away from other work in this area [2] bearing in mind the need for further investigations. I might add that given the quite strong links being put forward between autism and issues with oxidative stress (see here) and the quite consistent overlap between autism and ADHD (see here), future work might need to take quite a broad view of any relationship.

Of particular note to me in the Guney paper was mention of how differences in the oxidative stress index before and after intervention (i.e. medication) in their cohort might offer some new ideas about how certain types of medicines 'work' on cases of ADHD. So: "It was also determined that methylphenidate repairs the oxidative balance by increasing antioxidant defence mechanisms."

Methylphenidate (MPH) (known as Concerta or Ritalin) is a medication of choice for many people diagnosed with ADHD. Although by no means an expert on the whys and wherefores of how MPH works, discussions have always been a little unclear as to how something that looks chemically like an amphetamine (a stimulant) seems to have such a calming effect on some of the characteristics of ADHD. As a nootropic (so-called smart drug) the idea that MPH might work as a performance enhancer offers some clues as to how it might impact on ADHD type symptoms but still curiosity remains on it's important effects.

The idea that MPH might, in amongst its various proposed actions, also impact on processes pertinent to oxidative stress is an interesting one. Animal studies have previously suggested that administration of MPH might affect key compounds related to oxidative stress [3] in particular, related to oxidative defences. That being said, evidence has also been produced to suggest that MPH might do more to induce oxidative stress [4] than to solve any issues, so one has to be a little guarded about making too many sweeping generalisations. That drug dose might also be an important factor is something to take on board too.

Assuming further work is forthcoming to further elucidate any role for MPH in relation to the processes of oxidative stress, some intriguing prospects may lie on the research horizon.

Music: Dream Academy - Life In A Northern Town.

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[1] Guney E. et al. Attention Deficit Hyperactivity Disorder and oxidative stress: A short term follow up study. Psychiatry Res. 2015 Jul 8. pii: S0165-1781(15)00448-5.

[2] Joseph N. et al. Oxidative Stress and ADHD: A Meta-Analysis. J Atten Disord. 2013 Nov 14.

[3] Schmitz F. et al. Chronic methylphenidate administration alters antioxidant defenses and butyrylcholinesterase activity in blood of juvenile rats. Mol Cell Biochem. 2012 Feb;361(1-2):281-8.

[4] Martins MR. et al. Methylphenidate treatment induces oxidative stress in young rat brain. Brain Res. 2006 Mar 17;1078(1):189-97.

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ResearchBlogging.org Guney, E., Cetin, F., Alisik, M., Tunca, H., Tas Torun, Y., Iseri, E., Isik Taner, Y., Cayci, B., & Erel, O. (2015). Attention Deficit Hyperactivity Disorder and oxidative stress: A short term follow up study Psychiatry Research DOI: 10.1016/j.psychres.2015.07.003