Tryptophan, mood, and cognitive function.

In separate experiments we investigated the duration of the effects of acute tryptophan depletion (ATD) on mood and cognition. The results showed that ATD's effects consist of lowering of mood only in subjects with a family history of unipolar depression. A specific impairment of memory consolidation was seen in all subjects. In subjects without any vulnerability for mood disorders, performance on so-called 'frontal tasks,' measuring higher attentional functions tended to improve after ATD. The effects of ATD on mood and cognition were manifest as long as biochemical indices of low tryptophan remained low. In conclusion, ATD is a model for impairment of memory, next to being a model of mood disorders in vulnerable subjects. Moreover, ATD could be used as a challenge to demonstrate individual vulnerability of the serotonergic system. Copyright 2002 Elsevier Science (USA)