Table 1.
Characteristics of the study group according to BZD dose category (n = 2823)
| No BZD | BZD low dose ≤0.5 DDD | BZD intermediate dose >0.5–1 DDD | BZD high dose >1 DDD | ||
|---|---|---|---|---|---|
| n = 2404 | n = 288 | n = 74 | n = 57 | P value | |
| Sociodemographics | |||||
| Female gender (%) | 1584 (65.9) | 208 (72.2) | 42 (56.8) | 32 (56.1) | 0.02 |
| Age (years) mean (SD) | 40.9 (13.3) | 45.1 (11.9) | 46.6 (11.1) | 48.8 (9.1) | <0.001 |
| Education level (years) median (IQR) | 12.0 (10.0; 15.0) | 11.0 (10.0; 15.0) | 10.0 (9.0; 15.0) | 10.0 (9.0; 11.5) | <0.001 |
| Health indicators | |||||
| Non/mild drinker (%) | 1470 (61.1) | 189 (65.6) | 55 (74.3) | 41 (71.9) | 0.09 |
| Moderate drinker (%) | 534 (22.2) | 52 (18.1) | 11 (14.9) | 7 (12.3) | |
| Heavy drinker (%) | 400 (16.6) | 47 (16.3) | 8 (10.8) | 9 (15.8) | |
| Somatic disease (%) | 1259 (52.4) | 186 (64.6) | 50 (67.6) | 44 (77.2) | <0.001 |
| Psychopathology | |||||
| BAI, median (IQR) | 8.0 (3.0; 16.0) | 19.0 (9.0; 27.0) | 24.0 (13.8; 30.5) | 21.0 (12.1; 31.5) | <0.001 |
| IDS-SR mc, median (IQR) | 6.0 (2.0; 9.0) | 9.0 (5.0; 12.0) | 10.0 (8.0; 13.0) | 11.0 (8.5; 14.0) | <0.001 |
| Antidepressant use | |||||
| No AD use (%) | 1920 (79.9) | 159 (55.2) | 24 (32.4) | 16 (28.1) | <0.001 |
| AD low dose <0.5 DDD (%) | 58 (2.4) | 18 (6.3) | 3 (4.1) | 2 (3.5) | |
| AD intermediate dose 0.5–1 DDD (%) | 251 (10.4) | 50 (17.4) | 22 (29.7) | 15 (26.3) | |
| AD high dose >1 DDD (%) | 175 (7.3) | 61 (21.2) | 25 (33.8) | 24 (42.1) | |
| Reaction time | |||||
| RT (s), mean (95% CI) | 0.94 (0.93; 0.96) | 1.02 (0.98; 1.06) | 1.11 (1.05; 1.18) | 1.19 (1.12; 1.28) | <0.001* |
| BZD use (%) | |||||
| Duration (months) median (IQR) | N/A | 24.0 (5.0; 93.0) | 12.0 (3.0; 60.0)a | 36.0 (8.5; 96.0) | 0.04 |
| Type | 0.24 | ||||
| Short acting (t1/2 < 24 h, %) | N/A | 238 (82.6) | 60 (81.1) | 40 (70.2) | 0.093 |
| Long acting (t1/2 > 24 h, %) | N/A | 50 (17.4) | 14 (18.9) | 17 (29.8) | |
| BZD dependence (BENDEP-SRQ) | |||||
| Problematic use, median (IQR) | N/A | 9.1 (8.8; 9.5) | 10.5 (9.7; 11.2) | 11.3 (10.4; 12.2) | <0.001 |
| Preoccupation, median (IQR) | N/A | 12.3 (11.8; 12.8) | 14.4 (13.3; 15.4) | 15.6 (14.5; 16.6) | <0.001 |
| Lack of compliance, median (IQR) | N/A | 6.0 (5.0; 9.0) | 7.5 (5.3; 10.0) | 10.0 (7.8; 11.0) | <0.001 |
RT is the mean RT of 80 trials. 1 DDD is defined as 10 mg diazepam equivalents day−1. P is derived by analysis of variance (anova) for quantitative, normally distributed variables, Kruskal−Wallis test for continuous, non-normally distributed variables and χ2 statistics for categorical variables. Significance is inferred at P < 0.05. AD, antidepressant; BAI, Beck anxiety index; BENDEP-SRQ, Benzodiazepine Dependence Self Report Questionnaire; BZD, benzodiazepines; DDD, defined daily dose; IDS-SR mc, Mood cognition scale of the Inventory of Depressive Symptomatology; IQR, interquartile range; RT, reaction time.