Table 1.
Demographic and clinical descriptive information (a); Information regarding behavioural performance on the Reward Learning task (b); and computational modelling output (c)
| m/m-D (n=50) | n/l-D (n=37) | Group difference (95% CI) |
Association (coef, 95% CI) with | |||
|---|---|---|---|---|---|---|
| MADRS | IDS-SR | |||||
| a) | Age: mean, sd, range | 20.7 (2.3) 16 – 25 | 21.1 (1.7) 18 – 25 | [−0.5 ; 1.3] | ||
| Sex: female, n (%) | 41 (82) | 31 (84) | [−1.3 ; 1.0] | |||
| Education: high, n (%) | 42 (84) | 35 (95) | [−2.8 ; 0.4] | |||
| MADRS total score: mean, sd, range | ||||||
| at interview | 16.3 (3.9) 10–26 | 1.5 (2.0) 0–8 | [13.4 ; 16.3]* | |||
| at scan | 13.9 (5.0) 2–27 | 1.6 (2.1) 0–9 | [10.6 ; 14.0]* | |||
| IDS-SR total score: mean, sd, range | 23.4 (10.1) 5–42 | 6.2 (4.4) 0–20 | [13.7 ; 20.7]* | |||
| b) | RL task performance (gain trials only): mean, sd, range | |||||
| RT (ms) | 925 (127) 612–1194 | 903 (157) 601–1385 | [−83 ; 38] | 0.89 [−3.25 ; 5.04] | .46 [−2.11 ; 3.02] | |
| Non-responses | 1.12 (2.16) 0–14 | 1.05 (2.01) 0–7 | [−0.97 ; 0.84] | 0.01 [−0.06 ; 0.07] | .018 [−0.02 ; 0.06] | |
| Optimal choice accuracy | 0.83 (0.13) 0.56–0.99 | 0.84 (0.14) 0.56–1.00 | [−0.04 ; 0.07] | 6.41E-05 [−3.95E-03 ; 3.82E-03] | −1.21E-03 [−3.60E-03 ; 1.17E-03] | |
| Money won | 9.89 (1.00) 7.20–11.40 | 9.85 (1.22) 6.60–11.20 | [−0.51 ; 0.44] | 7.58E-03 [−2.46E-03 ; 3.97E-03] | −5.48E-03 [−0.03 ; 0.01] | |
| c) | Model fit measures: mean, sd, range | |||||
| LLHmodel | −24.98 (15.86) −52.54—0.69 | −23.41 (16.67) −51.48—0.69 | [−5.42 ; 8.55] | 2.0E-03 [−0.48 ; 0,47] | −0.13 [−0.42 ; 0,17] | |
| AIC a | 53.96 (31.72) 5.39–109.07 | 50.83 (33.33) 5.39–106.96 | [−17.10 ; 10.85] | 4.05E-03 [−0.95 ; 0.96] | 0.26 [−0.33 ; 0.84] | |
| BIC b | 58.69 (31.71) 10.05–113.84 | 55.56 (33.31) 10.15–111.72 | [−17.10 ; 10.84] | 3.91E-03 [−0.95 ; 0.96] | 0.26 [−.33 ; .84] | |
| PseudoR2 c | 0.54 (0.29) 0.04–0.99 | 0.57 (0.31) 0.03–0.99 | [−0.10 ; 0.16] | 7.42E-05 [−8.92E-03 ; 8.77E03] | −2.51E-03 [−7.95E03 ; 2.94E-03] | |
| Parameters: mean, sd, range | ||||||
| Learning Rate (α) | 0.20 (0.22) <0.01–0.90 | 0.26 (0.18) <0.01–0.71 | [−0.02 ; 0.15] | −2.96E-03 [−9.00E-03 ; 3.07E-03] | 2.67E-04 [−3.49E-03 ; 4.03E-03] | |
| Temperature (β) | 0.20 (0.22) <0.01->0.99 | 0.25 (0.25) <0.01->0.99 | [−0.05 ; 0.15] | −4.43E-03 [−1.12E02 ; 2.39E03] | −1.40E-04 [−4.40E-03 ; 4.12E-03] | |
| d) | ESM variables: mean, sd_b, sd_w, range | |||||
| Reward anticipation | 4.60 (0.63, 1.62) 1–7 | 5.25 (0.64, 1.32) 1–7 | [−0.92 ; −0.38]* | −0.05 [−0.07 ; −0.03]* | −0.03 [−0.04 ; −0.02]* | |
| Activity pleasantness | 4.98 (0.54, 1.53) 1–7 | 5.41 (0.53, 1.22) 1–7 | [−0.65 ; −0.20]* | −0.03 [−0.05 ; −0.02]* | −0.02 [−0.03 ; −0.01]* | |
Note. Abbreviations: sd=standard deviation, sd_b=between subjects standard deviation, sd_w=within subjects standard deviation, n=number of participants, MADRS= Montgomery-Âsberg Depression Scale, IDS-SR=Inventory of Depressive Symptomatology - Self-Report, RL=Reward Learning, RT=reaction time, ms=miliseconds, m/m-D=group of participants included based on the report of moderate symptom severity, n/l-D=group of participants included based on the report of low depressive symptom severity, CI=confidence interval, LLH=log-likelihood.
p<0.001
AIC: Akaike Information Criterion, calculated as −2*LLH+2*k, where k is the number of parameters (k=2)
BIC: Bayesian Information Criterion, calculated as −2*LLH+log(t)*k, where t is the number of trials (depends on how many responses a subject gave on the task) and k is the number of parameters (k=2).
PseudoR: calculated as -(LLHmodel-LLHchance)/LLHchance. LLHchance=log(0.5)*t, where t is the number of trials.