SPECT AND PET IMAGING IN MOOD DISORDERS

Single photon emission computed tomography (SPECT) and positron emissi on tomography (PET) studies are yielding a picture of clinical depress ion as a disorder associated with dysfunction in specific brain region s. These data support the view of depression as a disease of the brain in general and of the frontal and temporal lobes in particular. Front al lobe hypometabolism is emerging as a common final pathway for most types of primary and secondary depression, regardless of the original cause. The severity of depression is often related to the degree of fr ontal hypometabolism, and preliminary studies indicate that the hypome tabolism normalizes after treatment in concert with the patient's impr oved mood. Primary depression also is associated with abnormal activat ion of key brain areas, including discrete aspects of the frontal and temporal lobes, the amygdala, and the cingulate gyrus. Several areas o f research are currently under way using SPECT or PET to explore furth er the neuroanatomy of depression.