The results of this study suggested that late-life depression in some (but not all) patients might be related to disruption of mood-related frontolimbic networks by Aβ deposition, which may cause a vicious circle, further worsening the outcome of depression and impairing cognitive function.
In conclusion, the study selected circadian markers (acrophase, amplitude and circadian rhythmicity) that are easy to interpret clinically and that capture a holistic picture of circadian rhythm disruption in mood disorders.
Bipolar disorder is characterised by a primary disruption in mood.
In our studies of young people in the early stages of mood disorders, circadian disruption seems common and a potential avenue for targeted treatments.
However, most investigations of circadian rhythm disruptions in mood disorders are focused on older adult samples with established unipolar (UP) or bipolar disorders (BD).
Bipolar disorder is a chronic, recurring disorder associated with periodic disruptions in mood regulation, with annual treatment costs of $7,200 to $12,100 per year, 20% of which are attributable to hospitalizations [ 1, 2].
Disruption of the hypothesised functional linkage between mood and level of identification means that, despite experiencing persistent and exacerbated negative mood, a depressed individual may not derive the potential benefits of concrete processing on problem solving, planning, focused attention, and reduced emotional response, when faced with a loss or difficulty.
Circadian rhythm disturbances are of considerable interest to mood disorder researchers as many of the phenomena that accompany disruptions in the sleep wake cycle overlap with the symptoms of mood episodes or may trigger or prolong mood symptoms (e.g. McClung 2013; Robillard et al. 2013a).
One possibility is that the retrospective ratings of mood in the present study, used to minimise disruption of the worry process, may have been a less sensitive method of assessing state mood.
The finding that 5-HT mediates performance on the AGNG has been demonstrated before (6) and indicates that reduced 5-HT, rather than negative mood, causes the disruption of AGNG performance found in depression (16).
Miklowitz et al. [ 27] studied the effect of a modified MBCT protocol with two additional treatment elements specifically designed for patients with bipolar disorder: psychoeducation about mood changes and its provoking factors (e.g. interpersonal conflict, sleep/wake cycle disruptions) and upon identification of these factors bringing mindfulness to prodromal signs of mood elevation.
