ADHD - Brain Imaging
Despite numerous claims of imminent technological diagnostic breakthroughs, many involving brain imaging, it remains the case that “no biological marker is diagnostic for ADHD”.[1][2] Some research has indicated that there are population differences in brain volume in ADHD and non-ADHD children that persist through to adolescents.[5][6][7][8]
Critics highlight that the observed differences in brain size and function between the ADHD and non-ADHD groups are smaller than differences within the groups, and that many children with reduced brain volumes catch up later in life.[9] [10] They also claim that some studies that demonstrate population differences compared never medicated (non-ADHD) subjects to ADHD diagnosed subjects that had previously been exposed to psychostimulants that can cause shrinkage (atrophy) and other permanent physical brain abnormalities.[11] This raises questions about whether ADHD or ADHD treatments caused the observed differences.
DSM5 states that population studies have shown that ADHD diagnosed subjects tend to display increased slow wave electroencephalograms and reduced total brain volume in magnetic resonance images.[12] In 2013 the US Food and Drug Administration (FDA) approved Quantitative Electroencephalography (qEEG) as a means of identifying increased slow wave electroencephalograms. The FDA “has not cleared a qEEG biomarker to stand on its own as a diagnostic tool” but as a means of helping to confirm a behavioral based ADHD diagnosis and as offering hope of future biomarkers.[13] The research used to make this determination was conducted by the device manufacturer and did not include a non-ADHD control group so the prevalence of the same pattern of increased slow wave electroencephalograms was not determined in the general population. The take up rate of qEEG technology to confirm an ADHD diagnosis has been low with some diagnosticians describing it as unnecessary and expensive.[14]
References
[1] “We highlight several studies that have yoked brain imaging technologies to these stronger designs to illustrate how doing so can aid our understanding of disease mechanisms and in the foreseeable future can improve clinical diagnosis, prevention, and treatment planning for developmental psychopathologies”.Horga, G., Kaur, T., & Peterson, B. S. (2014). Annual research review: Current limitations and future directions in MRI studies of child- and adult-onset developmental psychopathologies. Journal of Child Psychology and Psychiatry, 55(6), 659–680. doi:10.1111/jcpp.12185
[2] ‘Despite significant advances in the state of the art, the potential clinical applications of neuroimaging research to the psychiatric care of children has yet to be realized.’ Gahan J. Pandina, ‘Review of Neuroimaging Studies of Child Adolescent Psychiatric Disorders from the past 10 years (Statistical Data Included)’, Journal of the American Academy of Child & Adolescent Psychiatry, Vol. 39 No. 7, July 2000,
pp. 815–28.
[3] Breggin, Talking Back to Ritalin, p. 236.
[4] Paul H. Wender, Attention-Deficit Hyperactivity Disorder in Adults, Oxford University Press, New York, 1995, p. 20.
[5] Castellanos, F. X., Lee, P. P., Sharp, W., Jeffries, N. O., Greenstein, D. K., Clasen, L. S., … Rapoport, J. L. (2002). Developmental trajectories of brain volume abnormalities in children and adolescents with attention-deficit/hyperactivity disorder. JAMA: Journal of the American Medical Association, 288(14), 1740–1748. doi:10.1001/jama.288.14.1740
[6] “Although gross differences in size or symmetry of brain structures can be quantified, individual cells and cell layers cannot yet be visualized. This means that, although the volume and shape of brain structures may be determined, the underlying cause of any differences cannot.” Sarah Durston, Hilleke E. Hulshoff Pol, B. J. Casey, Jay N. Giedd, Jan K. Buitelaar, Herman van Engeland, Anatomical MRI of the Developing Human Brain: What Have We Learned?, Journal of the American Academy of Child & Adolescent Psychiatry, Vol. 40 Issue 9, September 2001, pp. 1012–20.
[7] “Abnormal morphology was noted in the frontal cortices of patients with attention-deficit hyperactivity disorder, with reduced regional brain size localised mainly to inferior portions of dorsal prefrontal cortices bilaterally. Brain size was also reduced in anterior temporal cortices bilaterally. Prominent increases in grey matter were recorded in large portions of the posterior temporal and inferior parietal cortices bilaterally.” Sowell, E. R., Thompson, P. M., Welcome, S. E., Henkenius, A. L., Toga, A. W., & Peterson, B. S.(2003). Cortical abnormalities in children and adolescents with attention-deficit hyperactivity disorder. Lancet, 362(9397), 1699–1707.
[8] Patients showed significantly reduced brain activation in left and right superior temporal lobes, basal ganglia, and posterior cingulate during the oddball versus standard contrast. The activation differences in superior temporal lobes correlated inversely with response variability in control subjects but not in patients with ADHD... Brain abnormalities in patients with ADHD are not confined to fronto-striatal networks mediating executive functions but are also observed in temporo-striatal and cingulate regions during perceptive visual attention processes. Furthermore, temporal lobe dysfunction in the context of perceptual attention might be related to their behavioral problems with response variability.
KatyaRubiaaAnna B.SmithaMichael J.BrammerbEricTaylora
Temporal Lobe Dysfunction in Medication-Naïve Boys With Attention-Deficit/Hyperactivity Disorder During Attention Allocation and Its Relation to Response Variability https://doi.org/10.1016/j.biopsych.2007.02.024Get rights and content http://www.sciencedirect.com/science/article/pii/S0006322307001928
[9] Batstra et al., 2014 Batstra, L., Nieweg, E. H., & Hadders-Algra, M. (2014). Exploring five common assumptions on attention deficit hyperactivity disorder. Acta Paediatrica, 103(7), 696–700. doi:10.1111/apa.12642 [Google Scholar]).
[10] FB friend quotes (Shaw, Gogtay, & Rapoport, 2010Shaw, P., Gogtay, N., & Rapoport, J. (2010). Childhood psychiatric disorders as anomalies in neurodevelopmental trajectories. Human Brain Mapping, 31(6), 917–925. doi:10.1002/hbm.21028 [Google Scholar]).
[11] Peter R. Breggin, M.D., Talking Back to Ritalin: What Doctors Aren’t Telling You about Stimulants for Children, Common Courage Press, Monroe, 1998, p. 358.
[12] American Psychiatric Association (2013), Diagnostic and Statistical Manual of Mental Disorders. Fifth Edition, (DSM-5) pp. p61
[13] FDA 2015 FDA Science Forum Emerging Technologies • May 27 – 28, 2015 P99
https://www.fda.gov/downloads/scienceresearch/aboutscienceresearchatfda/ucm447461.pdf
[14] Dr. K.J. McLaughlin, BPE, CSCS, MASc. DC, Category : Mental Health • July 18, 2013 What the FDA Doesn’t Want You to Know About the New ADHD Test http://www.doctorshealthpress.com/brain-function-articles/mental-health/what-the-fda-doesnt-want-you-to-know-about-the-new-adhd-test/