Table 2.
Types of intervention trial and year of publication
| Type of trial | 1991 | 1995 | 2000 | Total |
| n = 25 (%) | n = 45 (%) | n = 107 (%) | n = 177 (%) | |
| Drug vs drug | 13 (52) | 20 (44) | 56 (52) | 89 (50) |
| Drug vs non-active (eg placebo) | 4 (16) | 9 (20) | 20 (19) | 33 (19) |
| Drug vs psychosocial | - | - | 7 (7) | 7 (4) |
| Drug vs biological non-drug (eg ECT) | 2 (8) | 2 (4) | 2 (2) | 6 (3) |
| Drug vs mixed (eg placebo AND psychotherapy) | - | - | 1 (<1) | 1 (<1) |
| Drug dose finding | 1 (4) | 2 (4) | 1 (<1) | 4 (2) |
| Total trials involving drugs | 20 (80) | 33 (73) | 87 (81) | 140 (80) |
| Biological non-drug vs biological non-drug | 1 (4) | 2 (4) | 3 (3) | 6 (3) |
| Psychosocial vs psychosocial | 4 (16) | 4 (9) | 5 (5) | 13 (7) |
| Psychosocial vs non-active | 3 (7) | 8 (7) | 11 (6) | |
| Biological non-drug vs non-active | 1 (2) | 3 (5) | 4 (2) |
ECT = electroconvulsive therapy