Multi-scale motility amplitude associated with suicidal thoughts in major depression

Area of Science:

• Neuroscience and Psychiatry
• Biomarker Discovery
• Chronobiology

Background:

• Major depression is a prevalent, disabling, and often recurrent disorder with a high suicide risk.
• Previous research on depression biomarkers may have been limited by viewing depression as a single entity.
• Alterations in daily activity rhythms are frequently observed in depressed individuals.

Purpose of the Study:

• To investigate the correlation between a vulnerability index (VI) derived from motility rhythms and suicidal thinking in depressed patients.
• To assess the potential of VI in differentiating between bipolar and unipolar major depression.
• To explore VI as an objective biomarker for suicide risk assessment.

Main Methods:

• Thirty-six patients with major depression (bipolar-I, bipolar-II, unipolar) were monitored using wrist-worn electronic actigraphs.
• A vulnerability index (VI) was calculated from multi-scale characteristics of daily motility rhythms.
• The VI was correlated with self-assessed suicidal thinking (wish to die).

Main Results:

• The VI showed a significant inverse correlation with suicidal thinking (r = -0.61 overall, r = -0.73 in bipolar subjects; p < 0.0001).
• The VI distinguished between bipolar and unipolar depression with high sensitivity (91.7%) and specificity (79.2%).
• These findings suggest VI is a promising objective measure related to depression severity and suicidality.

Conclusions:

• The vulnerability index (VI) may serve as a valuable biomarker for key features of major depression.
• VI shows potential in distinguishing between bipolar and unipolar depression subtypes.
• An objective VI biomarker could assist clinicians in assessing suicide risk, especially when patient self-reporting is limited.