Table 2.
Prevalence (%) and mean (SD) of non-suicidal self-harm in girls/women and boys/men at the three time points
| Girls/women | Boys/men | Total | |
|---|---|---|---|
| Any form of NSSI, n (%) | |||
| T1 | 221/493 (44.8%) | 187/489 (38.2%) | 408/982 (41.5%) |
| T2 | 241/495 (48.7%) | 176/480 (36.7%) | 419/979 (42.8%) |
| T3 | 72/327 (22.0%) | 32/229 (14.0%) | 104/556 (18.7%) |
| Repetitive NSSIa, n (%) | |||
| T1 | 102/493 (20.7%) | 79/489 (16.2%) | 181/982 (18.4%) |
| T2 | 127/495 (25.7%) | 76/480 (15.8%) | 205/979 (20.9%) |
| T3 | 37/327 (11.3%) | 21/229 (9.2%) | 58/556 (10.4%) |
| NSSI, total score, M (SD) | |||
| T1 | 4.24 (9.19) | 2.60 (6.42) | 3.47 (8.07) |
| T2 | 4.54 (9.05) | 2.85 (8.19) | 3.78 (8.85) |
| T3 | 1.69 (5.09) | 1.10 (4.38) | 1.45 (4.82) |
NSSI non-suicidal self-injury
aRepetitive NSSI = at least five instances of non-suicidal self-injury. Across the three time points, participants with no more than three missing values on the non-suicidal self-harm measure were included for data analysis; missing values were interpreted conservatively as the absence of self-harming behavior (i.e., imputing 0). As such, there were data available on NSSI for 983 participants at T1, 979 at T2, and 556 at T3