[Cholinergic hypothesis of depression]

Is acetylcholine implicated in depressive disorders? Biochemical methods studying the cholinergic system are not well set up. Only indirect elements could confirm the cholinergic hypothesis of affective disorders. Cholinergic agonists induce depressive symptomatology. Moreover, a central, cholinergic dysfunction could be an explanation of sleep disturbances and of neuroendocrine abnormalities seen in affective disorders. These observations could be applied in two ways: a more precise choice of antidepressive drugs, and the use of new tests developed to detect population with high depression risk.

Reduced platelet serotonin in depression

Platelet serotonin levels were measured in several psychiatric disorders to determine whether they distinguish among major depressive disorder (one or more depressive episodes and no manic episodes), dysthymic disorder (depressive neurosis), and schizophrenic and paranoid disorders. Serotonin levels in 141 subjects were determined using high performance liquid chromatography with electrochemical detection. Serotonin (5HT) levels in control subjects were significantly lower in males than in females. A marked reduction in 5HT levels, as compared to controls, was found in male and female patients with major depressive disorder, but not in dysthymic disorder. A slight but significant reduction in serotonin levels was found in female schizophrenic patients. The reduction in serotonin levels found in major depressive disorder could not be attributed to chronic antidepressant treatment. Liquid chromatography with electrochemical detection used in the present study permits a large-scale investigation.

[A case of dysthymic pathology in a 16-year-old adolescent]

Dysthymia in children and adolescents, illustrated by a sixteen-year-old-girl's clinical history, raises different diagnostic, therapeutic and prognostic problems. Diagnostic, since dysthymia in children and adolescents has specific peculiarities (often mixed manic episodes, variable expression of depressive affect according to age, problem of the meaning of "masked depression"; Diagnostic again, since it is difficult to collect clearcut evidence ascertaining the diagnosis of manic-depressive syndrome in children: genuine periodicity in the occurrence of dysthymic episodes, family history of psychoses (manic-depressive syndrome, periodic psychosis, or other types of psychosis) and effectiveness of lithium are reliable criteria; Finally, differential diagnosis with the two other types of childhood psychosis: affective psychoses and severe dysthymic disorders; Therapeutic: the problem is to know when and on what evidence treatment with lithium can be started and, if called for, discontinued.

[Reduction of platelet serotonin in major depression (endogenous depression)]

Serum serotonin (5-HT) levels were measured in several patients with psychiatric disorders using high pressure liquid chromatography with electrochemical detection. A marked reduction in 5-HT levels was found in male and female patients with major depressive disorder, as compared to controls, but not in dysthymic disorder. These modifications may constitute biochemical changes suggestive of major depressive disorders; they could not be attributed to chronic antidepressant treatment.