The amygdaloid complex and its implication in psychiatric disorders

Abstract

The amygdaloid complex is a group of nuclei located deep in the temporal lobe and closely involved in the limbic system. Its alteration has been associated with some psychiatric processes. In this article, an overall review was made of the published data concerning the amygdaloid complex in the most common psychiatric diseases. A damaged amygdaloid complex is commonly observed, that in the Klüver-Bucy syndrome presents the fullest expression. A decrease in the amygdaloid complex of schizophrenic patients has been observed. This finding was found bilaterally in men whereas in women it was only located in one hemisphere. This finding suggests that morphometric alterations in the amygdaloid complex are more diffuse and more severe in men with schizophrenia. This subcortical complex is larger in children with autism, but not in adolescents, in whom the amygdaloid complex volume matches the normal volume of an adolescent or an adult without this pathology. However, neuroanatomical studies have shown microscopic alterations. In patients with mood disorders, it has been reported that the left amygdaloid complex presents a lesser volume. Moreover, in frontotemporal dementia and Alzheimer disease a slight amygdaloid atrophia was found related to the healthy controls. It can be concluded that the amygdaloid complex is involved in several psychiatric processes, due to structural or functional damage. However, more studies are still needed in order to delimitate the real influence of the amygdaloid complex in these disorders.