Clinical Edge

Summaries of Must-Read Clinical Literature, Guidelines, and FDA Actions

Determining Objective Chronotype in Persons with BD

J Affect Disord; 2018 Dec; Kaufmann, et al

Wrist actigraphy for determination of daytime midpoints is a potential tool to identify objective chronotype in persons with bipolar disorder (BD), which is associated with later sleep and daily activity (evening rather than morning chronotype), a recent study found. Given the ubiquity of accelerometer-based devices (eg, actigraphs/smartphones) worn/used during daytime and tendency to recharge rather than wear at night, researchers assessed chronotype using daytime (rather than sleep) interval midpoints. 61 participants with BD type I (BD-I) or II (BD-II) and 61 healthy controls completed 25–50 days of continuous actigraphy. The Composite Scale of Morningness (CSM) was completed by a subset of this group. They found:

  • BD vs controls had delayed daytime midpoint and greater midpoint variability.
  • Stratifying by gender and age, females and adolescents with BD had delayed and more variable daytime midpoints vs controls.
  • Adults with BD had greater midpoint variability than controls.
  • Within-person mean and standard deviations of daytime midpoints were highly correlated with sleep midpoints.
  • Daytime midpoint mean was also significantly correlated with the CSM.


Kaufmann CN, Gershon A, Depp CA, Miller S, Zeitzer JM, Ketter TA. Daytime midpoint as a digital biomarker for chronotype in bipolar disorder. J Affect Disord. 2018;241:586-591. doi:10.1016/j.jad.2018.08.032.

This Week's Must Reads

Schizophrenia and Cardioprotective Treatment for MI, JAMA Psychiatry; ePub 2018 Oct 24; Kugathasan, et al

Schizophrenia and Goal-Directed Planning Examined, Schizophr Res; ePub 2018 Nov 22; Siddiqui, et al

Patient-Reported Outcomes for Weight Management, J Behav Health Serv Res; ePub 2018 Nov 21; Young, et al

Schizophrenia Linked with Aberrant Response to EBV, Schizophr Bull; ePub 2018 Nov 20; Dickerson, et al

Plasticity-Related Aberrations in Schizophrenia, Schizophr Res; ePub 2018 Nov 12; Smith, et al

Must Reads in Bipolar Disorder

Reduced Lateral OFC Volume and Suicidality in BD, Bipolar Disord; ePub 2018 Nov 24; Huber, et al

Subthreshold Pediatric BD Linked with Suicide Risk, Bipolar Disord; ePub 2018 Nov 27; Vaudreuil, et al

Mood Symptoms and Suicidality in Bipolar Disorder, Suicide Life Threat Behav; ePub 2018 Nov 19; Kamali, et al

Smokers with BD and Quit Rates Examined, Drug Alcohol Depend; 2018 Dec 1; Heffner, et al

Determining Objective Chronotype in Persons with BD, J Affect Disord; 2018 Dec; Kaufmann, et al