Editing Attention deficit hyperactivity disorder (section)

===Possible biomarkers for diagnosis===
Reviews of ADHD [[Biomarker (medicine)|biomarker]]s have noted that platelet [[monoamine oxidase]] expression, urinary [[norepinephrine]], urinary [[3-Methoxy-4-hydroxyphenylglycol|MHPG]], and urinary [[phenethylamine]] levels consistently differ between ADHD individuals and non-ADHD controls. These parameters could serve as prognostic biomarkers for ADHD, but more research is needed to establish their prognostic utility. Urinary and [[blood plasma]] phenethylamine concentrations are lower in ADHD individuals relative to controls.<ref>{{Cite journal |last1=Kusaga |first1=Akira |last2=Yamashita |first2=Yushiro |last3=Koeda |first3=Tastuya |last4=Hiratani |first4=Michio |last5=Kaneko |first5=Mika |last6=Yamada |first6=Shigeto |last7=Matsuishi |first7=Toyojiro |date=2002 |title=Increased urine phenylethylamine after methylphenidate treatment in children with ADHD |url=https://onlinelibrary.wiley.com/doi/10.1002/ana.10302 |journal=Annals of Neurology |language=en |volume=52 |issue=3 |pages=372–374 |doi=10.1002/ana.10302 |pmid=12205654 |issn=1531-8249}}</ref><ref>{{Cite journal |last1=Baker |first1=G. B. |last2=Bornstein |first2=R. A. |last3=Rouget |first3=A. C. |last4=Ashton |first4=S. E. |last5=van Muyden |first5=J. C. |last6=Coutts |first6=R. T. |date=1991-01-01 |title=Phenylethylaminergic mechanisms in attention-deficit disorder |url=https://www.sciencedirect.com/science/article/abs/pii/0006322391902073 |journal=[[Biological Psychiatry (journal)|Biological Psychiatry]] |volume=29 |issue=1 |pages=15–22 |doi=10.1016/0006-3223(91)90207-3 |pmid=2001444 |issn=0006-3223}}</ref> The two most commonly prescribed drugs for ADHD, [[amphetamine]] and [[methylphenidate]], increase phenethylamine [[biosynthesis]] in treatment-responsive individuals with ADHD.<ref name="Berry_2007">{{cite journal |vauthors=Berry MD |title=The potential of trace amines and their receptors for treating neurological and psychiatric diseases |journal=Reviews on Recent Clinical Trials |volume=2 |issue=1 |pages=3–19 |date=January 2007 |pmid=18473983 |doi=10.2174/157488707779318107 |quote=Although there is little direct evidence, changes in trace amines, in particular PE, have been identified as a possible factor for the onset of attention deficit/hyperactivity disorder (ADHD). ... Further, amphetamines, which have clinical utility in ADHD, are good ligands at trace amine receptors. Of possible relevance in this aspect is modafanil, which has shown beneficial effects in ADHD patients and has been reported to enhance the activity of PE at TAAR1. Conversely, methylphenidate, ...showed poor efficacy at the TAAR1 receptor. In this respect it is worth noting that the enhancement of functioning at TAAR1 seen with modafanil was not a result of a direct interaction with TAAR1. |citeseerx=10.1.1.329.563}}</ref> Lower urinary phenethylamine concentrations are associated with symptoms of inattentiveness in ADHD individuals.<ref name="Scassellati_2012">{{cite journal |vauthors=Scassellati C, Bonvicini C, Faraone SV, Gennarelli M |title=Biomarkers and attention-deficit/hyperactivity disorder: a systematic review and meta-analyses |journal=[[Journal of the American Academy of Child and Adolescent Psychiatry]] |volume=51 |issue=10 |pages=1003–1019.e20 |date=October 2012 |pmid=23021477 |doi=10.1016/j.jaac.2012.08.015}}</ref>