[Value of karyotype in psychiatry: the 3-D syndrome (dysthymia-dysgonosomia-deterioration). First clinical, cytogenetic, anatomical correlation].

The systematic study of the karyotype in Adult Psychiatry reveals among the group of periodical psychoses the existence of the 3-D Syndrome, marked by long clinical cycles, a course towards a dementia, the presence of a X-dysgonosomy with mosaicism, a relative and better clinical response with the use of lithium than with the use of tricyclic antidepressants. These characteristics discriminate the 3-D syndrome from the periodical manic depressive psychosis, which neither includes the course towards a dementia nor does it include until now identified cellular abnormalities. From the anatomical point of view the brain is quasi-normal, when the ultimate phase is a dementia. The 3-D Syndrome seems to be linked with a phenomenon of chromosomal instability. The caryotype takes a part among the usual biological tests in psychiatry.