A comparative study of bipolar disorder and attention deficit hyperactivity disorder through the measurement of regional cerebral blood flow

Abstract

Attention Deficit Hyperactivity Disorder (ADHD) and Bipolar Disorder (BPD) are two common neuropsychological disorders which are often present in a comorbid state. I used the results of cerebral blood flow studies made with Single Photon Emission Computer Tomography (SPECT), Positron Emission Tomography (PET) and Functional Magnetic Resonance Imaging (fMRI), to investigate a possible relationship between ADHD and BPD. The common areas of the brain involved in both BPD and ADHD appears to be the prefrontal cortex in its various components, the basal ganglia and possibly the cerebellum which, especially in the past, has been little studied by researchers in relation to ADHD and BPD. Among the differences the blood flow lateralization, present in BPD in states of altered mood, is evident with left hypoperfusion and right hyperperfusion during depression, the opposite in the case of manic state; in ADHD, the lateralization is less constant and of questionable interpretation. In BPD the involvement of a greater number of brain areas, especially the temporal lobe, is common. I advance the hypothesis that BPD progresses from ADHD secondary to expansion of perturbation in cerebral blood flow.