In summary, the number of postmortem studies on mood disorders is still very limited, but there is some evidence for changes in the basal ganglia and brainstem. Structural brain imaging studies support the notion that mood disorders are associated with regional structural brain abnormalities, in particular regions involved in mood regulation, such as the limbic portion of the basal ganglia and brainstem structures. Because small numbers of subjects were studied, only some postmortem studies distinguished between unipolar and bipolar depression. (46> Nevertheless, a recent review of the structural imaging studies(53) found this distinction worthwhile. The main abnormalities found in unipolar depression were smaller basal ganglia, cerebellum, and possibly frontal lobe, which may reflect local atrophy. Bipolar disorder appeared to be associated with larger third ventricle, smaller cerebellum, possibly smaller temporal lobe, and perhaps changes in the hippocampus. In both groups there seems to be an increased rate of subcortical white-matter lesions and periventricular hyperintensities. Further studies are needed, combining endocrine/biochemical parameters with structural parameters,(54> to identify the key regions involved in processes central to mood disorders such as changes in the regulation of the hypothalamic-pituitary-adrenal axis.(55 This would allow a focus on these regions in future postmortem-studies, which should yield promising results.
Alcoholism (Jable 4)
The best known neuropathological feature of alcoholism is Wernicke's encephalopathy, which is characterized by degenerative changes including gliosis and small hemorrhages in structures surrounding the third ventricle and aqueduct (i.e. the mamillary bodies, hypothalamus, mediodorsal thalamic nucleus, colliculi, and midbrain tegmentum), as well as cerebellar atrophy. Most of the clinical features associated with the Wernicke-Korsakoff syndrome including ophthalmoplegia, nystagmus, ataxia, and mental symptoms such as confusion, disorientation, and even coma can be related to damaged functional systems in the hypothalamus, midbrain, and cerebellum/56) Other important neuropathological manifestations of chronic alcoholism are central pontine myelinolysis, Marchiafava syndrome, and fetal alcohol syndrome (see Chapterii4.i2.2.3).
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