Editing Attention deficit hyperactivity disorder (section)

=== Neurotransmitter pathways ===
Previously, it had been suggested that the elevated number of [[dopamine transporters]] in people with ADHD was part of the pathophysiology, but it appears the elevated numbers may be due to adaptation following exposure to stimulant medication.<ref name="pmid22294258">{{cite journal |vauthors=Fusar-Poli P, Rubia K, Rossi G, Sartori G, Balottin U |title=Striatal dopamine transporter alterations in ADHD: pathophysiology or adaptation to psychostimulants? A meta-analysis |journal=[[The American Journal of Psychiatry]] |volume=169 |issue=3 |pages=264–272 |date=March 2012 |pmid=22294258 |doi=10.1176/appi.ajp.2011.11060940 |lccn=22024537 |hdl=11577/2482784 |doi-access=free |oclc=1480183 |eissn=1535-7228}}</ref> Current models involve the [[mesocorticolimbic projection|mesocorticolimbic dopamine pathway]] and the [[locus coeruleus-noradrenergic system]].<ref name="VTA+LC projection systems" /><ref name="Malenka ADHD neurosci" /><ref name="Malenka pathways" /> ADHD psychostimulants possess treatment efficacy because they increase neurotransmitter activity in these systems.<ref name="Malenka ADHD neurosci" /><ref name="Malenka pathways">{{cite book |vauthors=Malenka RC, Nestler EJ, Hyman SE |veditors=Sydor A, Brown RY |title=Molecular Neuropharmacology: A Foundation for Clinical Neuroscience |year=2009 |publisher=McGraw-Hill Medical |location=New York |isbn=978-0-07-148127-4 |pages=148, 154–157 |edition=2nd |chapter=Chapter 6: Widely Projecting Systems: Monoamines, Acetylcholine, and Orexin |quote={{abbr|DA|dopamine}} has multiple actions in the prefrontal cortex. It promotes the 'cognitive control' of behavior: the selection and successful monitoring of behavior to facilitate attainment of chosen goals. Aspects of cognitive control in which DA plays a role include working memory, the ability to hold information 'on line' in order to guide actions, suppression of prepotent behaviors that compete with goal-directed actions, and control of attention and thus the ability to overcome distractions. Cognitive control is impaired in several disorders, including attention deficit hyperactivity disorder.&nbsp;... Noradrenergic projections from the {{abbr|LC|locus coeruleus}} thus interact with dopaminergic projections from the {{abbr|VTA|ventral tegmental area}} to regulate cognitive control.&nbsp;... it has not been shown that {{abbr|5HT|serotonin}} makes a therapeutic contribution to treatment of ADHD.}}</ref><ref name="cognition enhancers" /> There may additionally be abnormalities in [[Serotonin|serotonergic]], [[glutamate (neurotransmitter)|glutamatergic]], or [[cholinergic]] pathways.<ref name="cognition enhancers" /><ref name="Cortese-2012">{{cite journal |vauthors=Cortese S |title=The neurobiology and genetics of Attention-Deficit/Hyperactivity Disorder (ADHD): what every clinician should know |journal=European Journal of Paediatric Neurology |volume=16 |issue=5 |pages=422–433 |date=September 2012 |pmid=22306277 |doi=10.1016/j.ejpn.2012.01.009}}</ref><ref name="pmid22939004">{{cite journal |vauthors=Lesch KP, Merker S, Reif A, Novak M |title=Dances with black widow spiders: dysregulation of glutamate signalling enters centre stage in ADHD |journal=[[European Neuropsychopharmacology]] |volume=23 |issue=6 |pages=479–491 |date=June 2013 |pmid=22939004 |doi=10.1016/j.euroneuro.2012.07.013 |s2cid=14701654}}</ref>

PET mapping of neocortex receptor distribution indicates that the distribution of μ-opioid receptors is the strongest contributor to cortical abnormalities in ADHD, followed by CB<sub>1</sub> cannabinoid receptors.<ref>{{Cite journal |last1=Hansen |first1=Justine Y. |last2=Shafiei |first2=Golia |last3=Markello |first3=Ross D. |last4=Smart |first4=Kelly |last5=Cox |first5=Sylvia M. L. |last6=Nørgaard |first6=Martin |last7=Beliveau |first7=Vincent |last8=Wu |first8=Yanjun |last9=Gallezot |first9=Jean-Dominique |last10=Aumont |first10=Étienne |last11=Servaes |first11=Stijn |last12=Scala |first12=Stephanie G. |last13=DuBois |first13=Jonathan M. |last14=Wainstein |first14=Gabriel |last15=Bezgin |first15=Gleb |date=2022 |title=Mapping neurotransmitter systems to the structural and functional organization of the human neocortex |journal=[[Nature Neuroscience]] |language=en |volume=25 |issue=11 |pages=1569–1581 |doi=10.1038/s41593-022-01186-3 |pmid=36303070 |pmc=9630096 |issn=1546-1726}}</ref>