Francisco A. Moreno, MD; Cynthia A. McGahuey, BA; Marlene P. Freeman, MD; and Pedro L. Delgado, MD
Objective: Although sex differences in
the prevalence of depression are well known, the
effects of sex on the underlying mechanisms of illness and on antidepressant action remain
less clear. Tryptophan depletion and catecholamine depletion (via
a-methylparatyrosine [AMPT] administration) are broadly utilized methods
for studying the effects of the safe and transient
reduction of serotonin and catecholamine neurotransmission, respectively. The present study
assessed the effects of sex on the mood response during acute monoamine depletion.
Method: Data on Hamilton Rating Scale
for Depression (HAM-D) scores during depletion tests were analyzed retrospectively in 59
subjects (41 women, 18 men) who underwent
tryptophan depletion and 39 subjects (25 women, 14
men) who underwent catecholamine depletion. All
subjects were in remission from a DSM-IV-defined major depressive episode. Data reviewed
included subjects enrolled between November 1993
and November 1997.
Results: Significant increases in
HAM-D scores were observed in response to both
depletion procedures, with a similar magnitude of change. Analysis of variance with repeated
measures of HAM-D scores revealed a significant main effect of time for tryptophan depletion (F
= 7.31, df = 3, p < .01) and for catecholamine depletion (F = 9.61, df = 4, p < .01).
Time-by-sex interaction was significant for tryptophan
depletion (F = 4.04, df = 3, p = .01), but not for
catecholamine depletion (F = 0.75, df = 4, p =
.57). Depressive symptoms were significantly
greater in women during tryptophan depletion (t test p
< .01), while no significant sex differences
were found during catecholamine depletion.
Conclusions: These findings suggest that
the effect of sex in depressive vulnerability may
be related to differential sex effects in
monoaminergic function.
J Clin Psychiatry 2006;67(10):1618-1623
© Copyright 2006 Physicians Postgraduate Press, Inc.