Assertion: tryptophan's level | /r/RelatedTo | depression
Facets:
Source sentences:
text: Serotonin is sometimes known as the happy chemical, because it appears to play an important role in regulating mood, and low levels of serotonin in the brain have been associated with depression.
text: Low levels of the chemical have been associated with depression, and increased serotonin levels brought on by medication are thought to decrease arousal.