Efficacy of early warning signals and spectral periodicity for predicting transitions in bipolar patients: An actigraphy study.

Early-warning signals (EWS) have been successfully employed to predict transitions in research fields such as biology, ecology, and psychiatry. The predictive properties of EWS might aid in foreseeing transitions in mood episodes (i.e.

Fractal biomarker of activity in patients with bipolar disorder.

Background: The output of many healthy physiological systems displays fractal fluctuations with self-similar temporal structures. Altered fractal patterns are associated with pathological conditions. There is evidence that patients with bipolar disorder have altered daily behaviors.

Stability of chronotype over a 7-year follow-up period and its association with severity of depressive and anxiety symptoms.

Background: Chronotype is an individual's preferred timing of sleep and activity, and is often referred to as a later chronotype (or evening-type) or an earlier chronotype (or morning-type). Having an evening chronotype is associated with more severe depressive and anxiety symptoms. Based on these findings it is has been suggested that chronotype is a stable construct associated with vulnerability to develop depressive or anxiety disorders.

ACTman: Automated preprocessing and analysis of actigraphy data.

Objectives: To introduce a novel software-library called Actigraphy Manager (ACTman) which automates labor-intensive actigraphy data preprocessing and analyses steps while improving transparency, reproducibility, and scalability over software suites traditionally used in actigraphy research practice.

Design: Descriptive.

Methods: Use cases are described for performing a common actigraphy task in ACTman and alternative actigraphy software.

The characteristics of psychotic features in bipolar disorder.

Background: In a large and comprehensively assessed sample of patients with bipolar disorder type I (BDI), we investigated the prevalence of psychotic features and their relationship with life course, demographic, clinical, and cognitive characteristics. We hypothesized that groups of psychotic symptoms (Schneiderian, mood incongruent, thought disorder, delusions, and hallucinations) have distinct relations to risk factors.

Methods: In a cross-sectional study of 1342 BDI patients, comprehensive demographical and clinical characteristics were assessed using the Structured Clinical Interview for DSM-IV (SCID-I) interview.

Social jetlag and depression status: Results obtained from the Netherlands Study of Depression and Anxiety.

Social jetlag, the misalignment between the internal clock and the socially required timing of activities, is highly prevalent, especially in people with an evening chronotype and is hypothesized to be related to the link between the evening chronotype and major depressive disorder. Although social jetlag has been linked to depressive symptoms in non-clinical samples, it has never been studied in patients with major depressive disorder (MDD). This study is aimed to study social jetlag in patients with major depressive disorder and healthy controls, and to further examine the link between social jetlag and depressive symptomatology.

An actigraphy study investigating sleep in bipolar I patients, unaffected siblings and controls.

Objectives: Disturbances in sleep and waking patterns are highly prevalent during mood episodes in bipolar disorder. The question remains whether these disturbances persist during phases of euthymia and whether they are heritable traits of bipolar disorder. The current study investigates objective sleep measures in a large sample of bipolar I patients, non-affected siblings and controls.

Coping with a life event in bipolar disorder: ambulatory measurement, signalling and early treatment.

Disruption of the biological rhythm in patients with bipolar disorder is a known risk factor for a switch in mood. This case study describes how modern techniques using ambulatory assessment of sleep parameters can help in signalling a mood switch and start early treatment. We studied a 40-year-old woman with bipolar disorder experiencing a life event while wearing an actigraph to measure sleep-wake parameters.

The relation between chronotype and treatment outcome with light therapy on a fixed time schedule.

Background: Seasonal affective disorder (SAD) is characterized by recurrent episodes of major depression in a seasonal pattern. The therapy of choice is light therapy (LT). It is suggested that LT should be administered relative to the chronotype of the patient, with the optimal timing earlier for morning than for evening types.