Table 2 Participants’ circadian rhythm measures, collected during first week of treatment, stratified by remission status and their relation to change in depression.

From: Circadian rhythm biomarker from wearable device data is related to concurrent antidepressant treatment response

Variables

Remission Status

     

Non-Remitters

(N = 24, 60%)

Remitters

(N = 16, 40%)

t-test

(DF = 38)

MW-U test

Δ

HDRS1

Δ

HDRS8

Mean (SD)

Median

(IQR)

Mean (SD)

Median

(IQR)

t

(P)

t

(P)

rs

(P)

Parametric Circadian Rhythm Measures

MESOR

(counts)

195.59 (91.80)

221.52 (111.76)

219.31 (102.37)

229.29 (73.38)

−0.76 (0.45)

−0.80 (0.42)

−0.10 (0.53)

−0.06 (0.73)

Amplitude (activity counts/minute)

165.45 (85.43)

172.89 (112.61)

156.99 (83.97)

182.08 (129.31)

0.31 (0.76)

0.14 (0.89)

0.11 (0.51)

0.09 (0.59)

CQ

0.83 (0.14)

0.86 (0.15)

0.75 (0.22)

0.78 (0.37)

1.41 (0.17)

0.64 (0.53)

0.38 (0.02*)

0.12 (0.44)

Acrophase

−4.08 (0.99)

−4.29 (0.77)

−4.16 (0.68)

−4.09 (0.99)

0.28 (0.78)

−0.36 (0.72)

−0.03 (0.84)

−0.04 (0.81)

Nonparametric Circadian Rhythm Measures

M10

311.38 (156.06)

307.62 (193.26)

333.07 (159.56)

363.76 (171.38)

−0.43 (0.67)

−0.58 (0.56)

−0.02 (0.90)

−0.05 (0.75)

L5

38.28 (33.07)

26.45 (63.94)

64.00 (73.28)

39.95 (33.10)

−1.51 (0.14)

−1.05 (0.29)

−0.24 (0.14)

−0.21 (0.19)

RA

0.74 (0.20)

0.79 (0.29)

0.72 (0.24)

0.82 (0.27)

0.32 (0.75)

0.21 (0.84)

0.29 (0.07)

0.18 (0.26)

IV

1.05 (0.30)

1.02 (0.33)

1.10 (0.28)

1.13 (0.28)

−0.53 (0.60)

−0.76 (0.45)

−0.11 (0.49)

−0.20 (0.21)

IS

0.35 (0.15)

0.36 (0.18)

0.32 (0.12)

0.34 (0.10)

0.64 (0.53)

0.35 (0.73)

0.20 (0.21)

0.03 (0.86)

  1. Non-Remitters: Week8-HDRS > 7. Remitters: Week8-HDRS ≤ 7.
  2. HDRS Hamilton depression rating scale, Week0-HDRS Hamilton depression rating scale score at baseline, Week1-HDRS Hamilton depression rating scale score after first week of treatment, Week8-HDRS Hamilton depression rating scale score after eight weeks of treatment, ΔHDRS1: change in depression severity after first week of treatment, ln(Week1-HDRS/ Week0-HDRS), with a higher value indicating more depression symptoms and a lower value indicating improvement in depression. ΔHDRS8: change in depression severity after eight weeks of treatment, ln(Week8-HDRS/ Week0-HDRS), with a higher value indicating more depression symptoms and a lower value indicating improvement in depression. N sample size, DF degrees of freedom = 38 for all the variables in the t-test. MW-U test Mann–Whitney U test, SD standard deviation, IQR interquartile range (75th percentile – 25th percentile). rs Spearman’s correlation coefficient, which was used to assess correlation between each of the parametric and nonparametric measures extracted from the first week of treatment and the change in depression after one week (ΔHDRS1) and eight weeks of treatment (ΔHDRS8). MESOR midline estimating statistic of rhythm, indicates the average activity level. Amplitude: difference between the highest point and average value of the circadian rhythm. CQ Circadian Quotient (amplitude/MESOR), which reflects robustness of the circadian rhythm. Acrophase: time of peak activity. M10: average activity count (min−1) during the most active 10 consecutive hours. L5: average activity count (min−1) during the least active 5 consecutive hours. RA relative amplitude, reflecting the difference between M10 and L5 activity. IV intradaily variability, estimates the circadian rhythm fragmentation by taking into account the extent and frequency of rest-activity transitions every hour (range: 0–2), with a higher value indicating a more fragmented rest-activity rhythm due to daytime rest/nappings and/or nighttime arousals. IS interdaily stability, estimates the consistency/stability of activity patterns over multiple days and its synchronization to the 24-hour light-dark cycle (range: 0–1), with a higher value indicating stable rhythm with good synchronization.
  3. The P-values that are statistically significant are indicated in bold for *P < 0.05 at α = 0.05.
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