Susceptibility to depression expressed as alterations in cortisol day curve: a cross-twin, cross-trait study.
OBJECTIVE
To examine, using a cross-twin cross-trait design, the hypotheses 1) that the genetic and environmental susceptibility to depression is expressed, in part, as alterations in cortisol day curves and 2) that cortisol abnormalities are not merely the consequence of depressive states or the stressors associated with its onset. Alteration of diurnal secretion of cortisol is a possible endophenotype of depression, as depressed patients show alterations in cortisol dynamics over the day.


METHODS
Salivary cortisol measurements were obtained in a sample of 279 twin pairs at 10 random times a day for 5 days. A structured clinical interview for DSM-IV (Diagnostic and Statistical Manual of Mental Disorders, 4th Edition) axis I mood disorder (SCID) was administered. Using multilevel regression analysis, the moderating influence of a lifetime diagnosis of depression in the co-twin on the association between time of day and cortisol concentrations in the proband twin was examined.


RESULTS
Diurnal variation in cortisol in the proband twin differed as a function of lifetime diagnosis of depression in the co-twin. In addition, this moderating effect was significantly stronger for dizygotic than for monozygotic twins.


CONCLUSIONS
Probands of co-twins with lifetime depression have a different diurnal cortisol profile than those without, suggesting that altered hypothalamic-pituitary-adrenal axis functioning is an indicator of depression susceptibility.
Wichers
Marieke C
MC
Department of Psychiatry and Neuropsychology, South Limburg Mental Health Research and Teaching Network, EURON, Maastricht University, Vijverdalseweg 1, Concorde Building, Maastricht, Netherlands. m.wichers@sp.unimaas.nl
Myin-Germeys
Inez
I
Jacobs
Nele
N
Kenis
Gunter
G
Derom
Catherine
C
Vlietinck
Robert
R
Delespaul
Philippe
P
Mengelers
Ron
R
Peeters
Frenk
F
Nicolson
Nancy
N
Van Os
Jim
J
D000293:Adolescent; D000328:Adult; D001143:Arousal / Q000502:physiology; D001530:Belgium; D002605:Character; D002940:Circadian Rhythm / Q000502:physiology*; D003865:Major Depressive Disorder / Q000097:blood* / Q000235:genetics*; D004200:Diseases in Twins / Q000097:blood* / Q000235:genetics*; D044127:Epigenesis, Genetic / Q000235:genetics; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics / Q000523:psychology; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D008875:Middle Aged; D010641:Phenotype; D010913:Pituitary-Adrenal System / Q000503:physiopathology; D011446:Prospective Studies; D012307:Risk Factors; D012463:Saliva / Q000737:chemistry
D006854:Hydrocortisone