The Effects of Tryptophan on Everyday Interpersonal Encounters and Social Cognitions in Individuals with a Family History of Depression.
BACKGROUND
Individuals with a family history of depression show subtle abnormalities in the processing of social stimuli. This could negatively affect their interpersonal functioning and contribute to their depression risk. Repeated administration of the serotonin precursor tryptophan has previously been shown to increase agreeable behavior and reduce quarrelsome behavior in irritable people, who are also considered at risk for depression.


METHODS
To examine the effects of tryptophan on social functioning in individuals with a family history of depression, 40 men and women with at least one first-degree relative with depression received tryptophan (1g three times a day) and placebo for 14 days each in a double-blind crossover design and recorded their social behavior and mood during everyday interpersonal encounters. Participants also provided daily ratings of their positive and negative cognitions concerning their social functioning.


RESULTS
Tryptophan improved mood. Unexpectedly, tryptophan increased quarrelsome behavior and reduced agreeable behavior, specifically during interactions at home. The behavioral effects of tryptophan were not moderated by mood or by the interaction partner. Negative social cognitions were lower when tryptophan was given second and lower during placebo when placebo was given second.


CONCLUSIONS
Overall, tryptophan may not alter social behavior in individuals with a family history of depression as it does in irritable people. However, the behavioral effects of tryptophan at home might be seen as a way for individuals with a family history of depression to achieve more control. Over time, this may positively influence the way they feel and think about themselves in a social context.
Department of Psychology (Mr Hogenelst and Dr aan het Rot), School of Behavioral and Cognitive Neurosciences (Mr Hogenelst and Dr aan het Rot), and University Medical Centre Groningen, Department of Psychiatry (Dr Schoevers), University of Groningen, Groningen, The Netherlands. k.hogenelst@rug.nl.
Koen
K
Hogenelst
Department of Psychology (Mr Hogenelst and Dr aan het Rot), School of Behavioral and Cognitive Neurosciences (Mr Hogenelst and Dr aan het Rot), and University Medical Centre Groningen, Department of Psychiatry (Dr Schoevers), University of Groningen, Groningen, The Netherlands.
Robert A
RA
Schoevers
Department of Psychology (Mr Hogenelst and Dr aan het Rot), School of Behavioral and Cognitive Neurosciences (Mr Hogenelst and Dr aan het Rot), and University Medical Centre Groningen, Department of Psychiatry (Dr Schoevers), University of Groningen, Groningen, The Netherlands.
Marije
M
Aan Het Rot
D000203:Activities of Daily Living / Q000523:psychology; D000293:Adolescent; D000328:Adult; D000339:Affect / Q000187:drug effects; D000368:Aged; D018687:Antidepressive Agents, Second-Generation / Q000008:administration & dosage*; D003071:Cognition / Q000187:drug effects*; D018592:Cross-Over Studies; D003866:Depressive Disorder / Q000188:drug therapy*; D004311:Double-Blind Method; D005190:Family; D005260:Female; D020022:Genetic Predisposition to Disease; D006798:Housing; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012919:Social Behavior; D014364:Tryptophan / Q000008:administration & dosage*; D055815:Young Adult
D018687:Antidepressive Agents, Second-Generation; D014364:Tryptophan
dysfunctional attitudes; major depressive disorder; mood; serotonin; social interaction