Table 1.
Category | Model | Variable description | Short name | Type | MARS discovery sample | MARS validation sample | p-valuea | ||
---|---|---|---|---|---|---|---|---|---|
Mean | SD | Mean | SD | ||||||
% | % | ||||||||
Sociodemographic data | 0 | Age at study inclusion (years) | age | N | 48.26 | 14.02 | 45.48 | 14.99 | 0.008c |
0 | Sex (% female) | sex | D | 53.72 % | 53.39 % | 0.941 | |||
0 | Living with a partner | spouse | D | 50.24% | 38.56% | 0.001b | |||
0 | School years of education (university not considered) (years) | education | N | 10.33 | 1.46 | 10.21 | 1.51 | 0.275 | |
0 | Being in training/retirement vs. employment | training_retirement | D | 25.42% | 22.46% | 0.393 | |||
0 | Employment status: unemployed/part time/full time | employment | N | 1.54 | 0.78 | 1.56 | 0.78 | 0.678 | |
Diagnosis | 0 | ICD-10 code for recurrent depressive disorders (F33) (%) | ICD10 | C | 64.63% | 66.95% | 0.536 | ||
History of depressive disorder | 0 | Age at disease onset (years) | age_on | N | 36.51 | 15.16 | 34.06 | 14.26 | 0.027b |
0 | Number of previous depressive episodes | prev_epi | N | 2.62 | 5.24 | 2.58 | 3.69 | 0.894 | |
0 | Any suicide attempt before current episode | s_history | D | 19.54% | 9.32% | 0.0001c | |||
0 | Psychotic symptoms in any previous episode | psychot_history | D | 11.15% | 3.81% | 0.0004c | |||
Family history | 0 | Family history of any mental disorders | fam_history | D | 63.19% | 64.41% | 0.760 | ||
0 | Family history of schizophrenic disorders | fam_F20_F25 | N d | 0.08 | 0.37 | 0.06 | 0.32 | 0.340 | |
0 | Family history of bipolar disorders | fam_F31 | N d | 0.05 | 0.31 | 0.08 | 0.37 | 0.348 | |
0 | Family history of affective disorders (except bipolar disorder) | fam_F32_ _F34 | N d | 0.88 | 0.95 | 0.87 | 0.96 | 0.857 | |
0 | Family history of attempted suicide | fam_X60 | N d | 0.23 | 0.58 | 0.16 | 0.46 | 0.082 | |
Information on current episode | 0 | Duration of the current episode (weeks) | index_d | N | 34.54 | 58.74 | 32.19 | 51.58 | 0.577 |
0 | ATRQ total score of treatment resistance for pre-medication | ATRQ_score | N | 1.09 | 0.90 | 1.01 | 1.33 | 0.311 | |
0 | Suicide attempt during the current episode | s_current | D | 10.31% | 2.54% | <0.0001c | |||
0 | Psychotic symptoms during the current episode | psychot_current | D | 10.43% | 2.97% | 0.0001c | |||
Basic medical and baseline laboratory data | 0 | Body height (m) | height | N | 1.72 | 0.09 | 1.72 | 0.09 | 0.545 |
0 | Body weight (kg) | weight | N | 25.65 | 6.07 | 25.94 | 5.28 | 0.504 | |
0 | Body mass index (m 2/kg) | BMI | N | 25.34 | 4.41 | 25.94 | 5.27 | 0.075 | |
0 | Heart rate (1/min) | HR | N | 82.75 | 13.16 | 80.45 | 12.14 | 0.016b | |
0 | Systolic blood pressure (mm Hg) | RRsys | N | 125.78 | 18.10 | 128.04 | 17.44 | 0.088 | |
0 | Diastolic blood pressure (mm Hg) | RRdia | N | 78.70 | 11.06 | 79.10 | 11.97 | 0.640 | |
0 | Morning cortisol level (µg/l) | cort_basal | N | 200.53 | 39.61 | 206.70 | 63.54 | 0.068 | |
0 | Thyroid stimulating hormone level (µIU/l) | TSH | N | 1.47 | 1.02 | 1.75 | 1.21 | 0.0005c | |
0 | Free T3 hormone level (pmol/l) | fT3 | N | 4.57 | 0.93 | 4.45 | 0.62 | 0.065 | |
0 | Free T4 hormone level (pmol/l) | fT4 | N | 16.16 | 9.23 | 15.29 | 3.57 | 0.158 | |
0 | CRP level (mg/l) | CRP | N | 1.49 | 2.92 | 2.83 | 9.00 | 0.0002c | |
0 | HBA1c level (mmol/mol) | HbA1C | N | 5.34 | 0.34 | 5.31 | 0.35 | 0.209 | |
Life events | 0 | Sum of life events | L-Event | N | 29.50 | 10.46 | 30.23 | 11.83 | 0.359 |
0 | Stress-weighted sum of life events | wL-Event | N | 82.30 | 38.65 | 86.36 | 47.94 | 0.177 | |
Baseline psychopathology | 0 | Symptom checklist-90-R (SCL-90R) for somatization | scl_som | N | 0.97 | 0.64 | 0.99 | 0.64 | 0.488 |
0 | SCL-90R for compulsiveness | scl_comp | N | 1.77 | 0.72 | 1.70 | 0.69 | 0.177 | |
0 | SCL-90R for uncertainty in social contact | scl_uncert | N | 1.30 | 0.77 | 1.33 | 0.83 | 0.630 | |
0 | SCL-90R for depression | scl_dep | N | 2.08 | 0.73 | 2.06 | 0.76 | 0.660 | |
0 | SCL-90R R for anxiety | scl_anx | N | 1.37 | 0.70 | 1.31 | 0.75 | 0.258 | |
0 | SCL-90R for aggressiveness/hostility | scl_agg | N | 0.77 | 0.60 | 0.86 | 0.69 | 0.046b | |
0 | SCL-90R for phobic anxiety | scl_pho | N | 0.88 | 0.75 | 0.94 | 0.83 | 0.283 | |
0 | SCL-90R for paranoid ideation | scl_par | N | 0.92 | 0.72 | 0.99 | 0.82 | 0.218 | |
0 | SCL-90R for psychoticism | scl_psy | N | 0.83 | 0.55 | 0.80 | 0.54 | 0.507 | |
Personality items | 0 | Eysenck Personality Questionnaire (EPQ)-RK neuroticism | epq_neu | N | 6.85 | 2.50 | 6.84 | 2.73 | 0.938 |
0 | EPQ-RK psychoticism | epq_psy | N | 1.92 | 1.24 | 2.16 | 1.40 | 0.010b | |
0 | EPQ-RK extraversion | epq_ext | N | 5.20 | 2.97 | 5.07 | 3.03 | 0.567 | |
0 | Tridimensional Personality Questionnaire (TPQ) Harm avoidance total | tpq_ha | N | 20.63 | 5.58 | 20.27 | 5.92 | 0.386 | |
0 | TPQ Novelty Seeking total | tpq_ns | N | 13.07 | 3.81 | 14.04 | 4.41 | 0.001b | |
0 | TPQ Reward Dependence total | tpq_rd | N | 17.75 | 3.30 | 17.50 | 3.84 | 0.318 | |
0 | TPQ Reward Dependence–Subscale Persistence | tpq_rd2 | N | 4.81 | 1.70 | 4.88 | 1.86 | 0.623 | |
HAM-D single items (baseline) | 1, 3 | 21 HAM-D single items (baseline) | HAM-D0_01-HAM-D0_21 | N | N/Te | N/Te | N/Te | N/Te | N/Te |
Early partial response (at week 2) | 2, 3 | HAM-D early partial response (≥25% reduction) after 2 weeks | HD_2WE | D | N/Te | N/Te | N/Te | N/Te | N/Te |
N numerical, D dichotomous, C categorical
aTwo-sided comparisons between the MARS discovery and validation samples (Fisher’s exact test and Fisher-Freeman-Halton test for dichotomous and categorical variables; Student’s t-test for numerical variables)
bNominal significance (p < 0.05)
cSignificance after Bonferroni correction for multiple testing, here: p < 0.05/50 = 0.001
dTo allow optimal use in a parametric test, variables were coded as 0 (no relative affected), 1 (only second-degree relatives affected), and 2 (first-degree or first-degree and second-degree relatives affected).
eNot tested as these items were not part of model 0.