Oral Presentation Australian & New Zealand Obesity Society 2014 Annual Scientific Meeting

Circadian drivers of poor mental and physical health (#27)

Ian Hickie 1
  1. The University of Sydney, Sydney, NSW, Australia


Episodic bipolar and unipolar mood disorders are characterized by disruptions in sleep-wake cycle, patterns of physical activity and circadian rhythms. These phenomena are most evident in those who experience recurrent mania or ‘atypical’ depressive episodes. As 75% of major mental disorders emerge before age 25 years, the focus on recording the earliest features of these disorders in teenagers and young adults


We have investigated sleep-wake cycle, physical activity and circadian features in young persons with emerging mood disorders in two large clinical samples (n=307, 30% bipolar-type, mean age = 19 years; n=1797, 16% bipolar-type, mean age = 18 years). Additionally, we are investigating phenotypic and circadian features in a longitudinal study of adolescent twins (n=2459, mean age=16 years). Measures include objective and prolonged actigraphic-derived assessments of 24-hour sleep-wake cycles and daytime physical activity, early evening melatonin secretion patterns and relevant metabolic function parameters in selected sub-groups.


In clinical samples, there is evidence of delayed onset and offset of sleep-wake cycles, reduced day-time physical activity and disrupted onset of night-time melatonin release in up to half of young persons with emerging mood disorders. These features are more pronounced in those with more severe conditions and those with a history of mania or hypomania episodes. In twins, sleep-wake cycle phenotypes are predicted by shared genetic characteristics and appear to have their own longitudinal associations with the ‘atypical’ as distinct from more classical ‘anxious depression’ illness-type. Additionally, hypomanic-type features are extremely common in young people, with about one-in-five reporting at least one episode of sleep disturbance and activitation prior to age 25 years.


Delayed sleep offset and disrupted circadian function are characteristics of a major subgroup of young people with emerging mood disorders. While under strong genetic control, these features are exacerbated by other environmental and illness-related factors. These studies provide unique data concerning relationships between circadian factors and the onset and course of depression, and other comorbidities, in young persons during the early phases of illness. Circadian systems may represent a key target for behavioural or pharmacological treatments of depression independent of other illness characteristics.

  1. Hickie IB, Rogers NL. (2011) Novel melatonin-based therapies: Potential advances in the treatment of major depression. The Lancet, 378(9791): 621-631.
  2. Naismith SL, Hermens DF, Ip TKC, Bolitho S, Scott E, Rogers NL, Hickie IB (2012) Circadian profiles in young people during the early stages of affective disorder, Translational Psychiatry, e123.
  3. Scott EM, Hermens DF, Naismith SL, Guastella AJ, De Regt T, White D, Lagopoulos J Hickie IB. (2013) Distinguishing young people with emerging bipolar disorders from those with unipolar depression. Journal of Affective Disorder, 144, 208–215.
  4. Robillard R, Naismith SL, Rogers NL, Ip TKC, Hermens DF, Scott EM, Hickie IB (2013) Delayed sleep phase and sleep disturbances in young people with unipolar or bipolar affective disorders, Journal of Affective Disorders, 145: 260-263.
  5. Hickie IB, Scott J, Hermens DF, Scott EM, Naismith SL, Guastella AJ, Glozier N, McGorry P. (2013) Clinical classification in mental health at the cross-roads: which direction next? BMC Medicine, 11:125
  6. Hickie IB , Naismith1 SL , Robillard R, Scott EM, Hermens DF. Manipulating the sleep-wake cycle and circadian rhythms to improve clinical management of major depression. (2013) BMC Medicine, 11:79, doi:10.1186/1741-7015