Dysregulation of the sympathetic nervous system, hypothalamic-pituitary-adrenal axis and executive function in individuals at risk for suicide.
BACKGROUND
Suicidal behaviour aggregates in families, and the hypothalamic-pituitary-adrenal (HPA) axis and noradrenergic dysregulation may play a role in suicide risk. It is unclear whether stress dysregulation is a heritable trait of suicide or how it might increase risk. We investigated stress reactivity of the autonomic nervous system and the HPA axis in suicide predisposition and characterized the effect of this dysregulation on neuropsychologic function.


METHODS
In this family-based study of first-degree relatives (n = 14) of suicide completers and matched controls with no family or personal history of suicidal behaviour (n = 14), participants underwent the Trier Social Stress Test (TSST). We used salivary α-amylase and cortisol levels to characterize stress reactivity and diurnal variation. We administered a series of neuropsychologic and executive function tests before and after the TSST.


RESULTS
Despite normal diurnal variation, relatives of suicide completers exhibited blunted cortisol and α-amylase TSST reactivity. Although there were no baseline differences in conceptual reasoning, sustained attention or executive function, the relatives of suicide completers did not improve on measures of inhibition upon repeated testing after TSST. Secondary analyses suggested that these effects were related to suicide vulnerability independent of major depression.


CONCLUSIONS
The sample size was small, and the design prevents us from disentangling our findings from the possible traumatic consequences of losing a relative by suicide.


CONCLUSIONS
Blunted stress response may be a trait of suicide risk, and impairment of stress-induced executive function may contribute to suicide vulnerability.
McGirr
Alexander
A
McGill Group for Suicide Studies, Douglas Hospital Research Centre, McGill University, 6875 LaSalle Blvd., Montréal, QC H4H1R3.
Diaconu
Gabriel
G
Berlim
Marcelo T
MT
Pruessner
Jens C
JC
Sablé
Rebecca
R
Cabot
Sophie
S
Turecki
Gustavo
G
D000328:Adult; D000368:Aged; D002940:Circadian Rhythm / Q000502:physiology; D003071:Cognition / Q000502:physiology; D003865:Major Depressive Disorder / Q000503:physiopathology / Q000523:psychology; D039721:Diagnostic and Statistical Manual of Mental Disorders; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000378:metabolism; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010913:Pituitary-Adrenal System / Q000503:physiopathology*; D012306:Risk; D012463:Saliva / Q000737:chemistry; D012931:Social Environment; D013315:Stress, Psychological / Q000503:physiopathology / Q000523:psychology; D013405:Suicide / Q000523:psychology*; D013564:Sympathetic Nervous System / Q000503:physiopathology*; D055815:Young Adult; D000516:alpha-Amylases / Q000378:metabolism
D000516:alpha-Amylases; D006854:Hydrocortisone