Repeated salivary daytime cortisol and onset of mood episodes in offspring of bipolar parents.

Sarah M Goodday,Anne Duffy,Charles Keown-Stoneman,Paul Grof,Julie Horrocks

doi:10.1186/s40345-016-0053-5

Abstract

BackgroundDifferences in cortisol secretion may differentiate individuals at high compared to low genetic risk for bipolar disorder (BD) and predict the onset or recurrence of mood episodes. The objectives of this study were to determine if salivary cortisol measures are: (1) different in high-risk offspring of parents with BD (HR) compared to control offspring of unaffected parents (C), (2) stable over time, (3) associated with the development of mood episode onset/recurrence, and (4) influenced by comorbid complications.MethodsFifty-three HR and 22 C completed salivary cortisol sampling annually for up to 4 years in conjunction with semi-structured clinical interviews. The cortisol awakening response (CAR), daytime cortisol [area under the curve (AUC)], and evening cortisol (8:00 p.m.) were calculated.ResultsThere were no differences in baseline CAR, AUC and evening cortisol between HR and C (p = 0.38, p = 0.30 and p = 0.84), respectively. CAR, AUC and evening cortisol were stable over yearly assessments in HR, while in Cs, evening cortisol increased over time (p = 0.008), and CAR and AUC remained stable. In HR, AUC and evening cortisol increased the hazard of a new onset mood disorder/recurrence by 2.7 times (p = 0.01), and 3.5 times (p = 0.01), respectively, but this was no longer significant after accounting for multiple comparisons.ConclusionsSalivary cortisol is stable over time within HR offspring. However, between individuals, basal salivary cortisol is highly variable. More research is needed, with larger samples of prospectively studied HR youth using a more reliable method of cortisol measurement, to determine the potential role of cortisol in the development of mood disorders.Electronic supplementary materialThe online version of this article (doi:10.1186/s40345-016-0053-5) contains supplementary material, which is available to authorized users.

Highlights

Differences in cortisol secretion may differentiate individuals at high compared to low genetic risk for bipolar disorder (BD) and predict the onset or recurrence of mood episodes
This study examined the longitudinal association between salivary cortisol as measured by cortisol awakening response (CAR), area under the curve (AUC) and mean evening cortisol and mood episodes in offspring at high familial risk
In high-risk offspring with a lifetime mood disorder, a comorbid lifetime history of a substance use disorders (SUD) influenced stability of daily secretion (AUC), where cortisol levels decreased over time among those with a prior SUD and remained stable among those without a SUD; the interaction pertaining to SUD did not maintain significance after adjustment for multiple comparisons

Summary

Introduction

Differences in cortisol secretion may differentiate individuals at high compared to low genetic risk for bipolar disorder (BD) and predict the onset or recurrence of mood episodes. The objectives of this study were to determine if salivary cortisol measures are: (1) different in high-risk offspring of parents with BD (HR) compared to control offspring of unaffected parents (C), (2) stable over time, (3) associated with the development of mood episode onset/recurrence, and (4) influenced by comorbid complications. Hypothalamic–pituitary–adrenal (HPA) axis dysregulation is the most consistent biological predictor of Goodday et al Int J Bipolar Disord (2016) 4:12 mood episode recurrence in both BD and melancholic depressed patients (Carroll et al 1981; Duffy et al 2012), while non-suppression to dexamethasone challenge has been used as a barometer for illness activity (Deshauer et al 1999; Stetler and Miller 2011). The HPA axis is central in controlling reactions to stress and regulating emotional processes and there is an established association between mood symptoms and hypercortisolaemic states providing strong evidence of the biological plausibility of this association (Duffy et al 2012)

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