[L-tryptophan plasma levels in treatment resistant depressive states]

10 to 30% of depressions are resistant to standard treatment. Different therapeutic strategies are used to treat the resistant depressions. Therefore, before initiating an antidepressant treatment, it would be important to know which patients will probably not respond to a standard treatment. Numerous studies have shown that serotonin is involved in depressive illness and its synthesis in the brain is dependent on the availability of tryprophan from plasma. As tryptophan plasma level is decreased in depression, resistant depressions may also be characterized by alterations of tryptophan plasma level. 141 depressed patients were admitted in our psychiatric unit in Geneva between 1984 and 1990. 36 were diagnosed as treatment resistant depression. Although treatment resistant patients group had more women and a more severe score of depression on the AMDP-4 scale, we did not observe a significant difference in tryptophan plasma level compared to patients who respond to treatment.