Tryptophan depletion affects heart rate variability and impulsivity in remitted depressed patients with a history of suicidal ideation.
BACKGROUND
Depression is a major risk factor for cardiovascular disease. An important risk factor for cardiovascular disease, low heart rate variability, often has been found in depressed patients and has been associated with impulsivity. The present study investigated whether experimental lowering of serotonin would decrease heart rate variability and increase impulsivity in remitted depressed patients, in particular in those patients with disturbed impulse control.


METHODS
Nineteen patients in remission from depression received high-dose and low-dose acute tryptophan depletion in a randomized, counterbalanced, double-blind crossover design. Heart rate variability and impulsivity were assessed during each acute tryptophan depletion session and during a baseline session. Suicidal ideation during past depression was used as an index for individual differences in impulse control.


RESULTS
High-dose acute tryptophan depletion led to a larger increase in depressive symptoms than did low-dose acute tryptophan depletion. High-dose acute tryptophan depletion decreased heart rate variability and increased impulsivity and anxiety, but only in patients with a history of suicidal ideation. Symptom effects of high-dose acute tryptophan depletion correlated with low heart rate variability at baseline.


CONCLUSIONS
Depressed patients who have problems with controlling impulsivity might be more at risk for developing cardiovascular disease, possibly related to increased vulnerability to impaired 5-hydroxytryptamine function.
Booij
Linda
L
Department of Psychology, Leiden University, Wassenaarseweg, Leiden, the Netherlands.
Swenne
Cees A
CA
Brosschot
Jos F
JF
Haffmans
P M Judith
PM
Thayer
Julian F
JF
Van der Does
A J Willem
AJ
D000328:Adult; D000596:Amino Acids / Q000097:blood; D018592:Cross-Over Studies; D003865:Major Depressive Disorder / Q000097:blood* / Q000378:metabolism / Q000523:psychology; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007175:Impulsive Behavior / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D011597:Psychomotor Performance / Q000502:physiology; D012701:Serotonin / Q000378:metabolism*; D013405:Suicide / Q000523:psychology; D014364:Tryptophan / Q000008:administration & dosage / Q000097:blood / Q000172:deficiency*
D000596:Amino Acids; D012701:Serotonin; D014364:Tryptophan