Research from the University of Cambridge finds that “dopamine dysregulation per se is unlikely to be the primary cause underlying attention deficit/hyperactivity disorder pathology in adults.” Using positron emission tomography (PET) imaging, the researchers found no difference in the effects of Ritalin on dopamine receptors in people with and without ADHD diagnoses.
Campo, N., Fryer., T., Hong, Y., Smith, R., et al; A positron emission tomography study of nigro-striatal dopaminergic mechanisms underlying attention: implications for ADHD and its treatment. Brain. 136(11) 3252-3270
Of further interest:
Brain imaging study demonstrates that dopamine dysregulation is not the cause of ADHD (University of Cambridge Press Release)
Imaging study shows dopamine dysfunction is not the main cause of Attention Deficit Hyperactivity Disorder (ADHD) (University of Cambridge)
Dopamine may not be behind attention disorder: Researchers (Business Standard)
Dopamine Dysfunction Not to Blame for ADHD (Bioscience Technology)
Chemical Imbalance Is Probably Not Behind ADHD (PsychCentral)