Sex differences in diencephalon serotonin transporter availability in major depression.
BACKGROUND
Major depression is more prevalent in women than men. The present study evaluated if previous findings that demonstrated decreased 5-hydroxytryptamine (5-HT) transporter availability in depressed patients would be confirmed in a larger sample and also evaluated sex differences.


METHODS
Depressed (n = 32) and healthy subjects (n = 32), including 16 pairs of women and men, participated in an iodine-123-2 beta-carbomethoxy-3beta-(4-iodophenyltropane) ([(123)I]beta-CIT) single photon emission computed tomography (SPECT) and a magnetic resonance imaging (MRI) scan. Participants were administered [(123)I]beta-CIT (225.7 +/- 3.7 MBq) and imaged 23.0 +/- 1.6 hours later. Statistical analyses included analysis of variance and a regression analysis of the main and interactive effects of age, sex, and depression.


RESULTS
Overall, depressed patients demonstrated 12% lower diencephalon and no change in striatal or brainstem [(123)I]beta-CIT uptake. Significant age by sex, sex by depression, and age by sex by depression interactions were noted due to 22% lower diencephalon [(123)I]beta-CIT uptake in depressed women compared with less than a 1% decrease in depressed men.


CONCLUSIONS
As observed previously, diencephalon 5-HT transporter availability is decreased in depressed patients. However, the decrease appears to be sex-specific and age-dependent. These findings suggest that serotonergic mechanisms mediating depressed mood differ between men and women in an age-dependent manner and may explain why young women respond better to treatment with selective serotonin reuptake inhibitor (SSRI) antidepressants.
Staley
Julie K
JK
Department of Psychiatry, Yale University School of Medicine and West Haven VA Connecticut Health Care System, CT 06516, USA. julie.staley@yale.edu
Sanacora
Gerard
G
Tamagnan
Gilles
G
Maciejewski
Paul K
PK
Malison
Robert T
RT
Berman
Robert M
RM
Vythilingam
Meena
M
Kugaya
Akira
A
Baldwin
Ronald M
RM
Seibyl
John P
JP
Charney
Dennis
D
Innis
Robert B
RB
D000328:Adult; D001931:Brain Mapping; D016022:Case-Control Studies; D003042:Cocaine / Q000031:analogs & derivatives / Q000493:pharmacokinetics; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging / Q000378:metabolism*; D004027:Diencephalon / Q000000981:diagnostic imaging / Q000378:metabolism*; D050483:Dopamine Plasma Membrane Transport Proteins / Q000378:metabolism; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D007456:Iodine Isotopes / Q000493:pharmacokinetics; D008297:Male; D008875:Middle Aged; D050486:Serotonin Plasma Membrane Transport Proteins / Q000378:metabolism*; D012727:Sex Characteristics; D013223:Statistics as Topic; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
D050483:Dopamine Plasma Membrane Transport Proteins; D007456:Iodine Isotopes; D050486:Serotonin Plasma Membrane Transport Proteins; C069723:2beta-carbomethoxy-3beta-(4-iodophenyl)tropane; D003042:Cocaine