L‐Tryptophan is the unique protein amino acid (AA) bearing an indole ring: its
biotransformation in living organisms contributes either to kee** this chemical group in …

Major depression is a debilitating and recurrent disorder with a substantial lifetime risk and a
high social cost. Depressed patients generally display co-morbid symptoms, and depression …

Alterations in brain tryptophan levels cause changes in brain serotonin synthesis, and this
has been used to study the implication of altered serotonin levels in humans. In the acute …

Manipulations of the sleep-wake cycle, whether of duration (total or partial sleep deprivation
[SD]) or timing (partial SD, phase advance), have profound and rapid effects on depressed …

Total sleep deprivation (TSD) for one whole night improves depressive symptoms in 40–
60% of treatments. The degree of clinical change spans a continuum from complete …

OBJECTIVE: Sleep deprivation has been shown to have an antidepressant benefit in a
subgroup of depressed patients. Functional imaging studies by the authors and others have …

Depression is a common disorder that impacts on all aspects of a person's life. For the past
10 years, clinicians have focused on serotonin in their treatment of depression. This is …

Psychiatric chronotherapeutics is the controlled exposure to environmental stimuli that act
on biological rhythms in order to achieve therapeutic effects in the treatment of psychiatric …

We review here the rapid tryptophan depletion (RTD) methodology and its controversial
association with depressive relapse. RTD has been used over the past decade to deplete …

Background: The number of studies using tryptophan depletion (TD) challenge has
increased markedly in the past few years. Recently, a number of negative results have been …