|  | Autistic | Possibly autistic | Combined autistic/possibly autistic | Non-autistic | Comparisons (autistic vs. possibly autistic vs. non-autistic) |
---|---|---|---|---|---|---|
N = 308 | N = 113 | N = 421 | N = 268 |  | ||
N (%)/Mean (SD) | ||||||
SBQ-R mean item scores | Lifetime suicidality | 3.04 (.893) | 2.66 (.935) | 2.94 (.92) | 2.11 (.965) | H(2) = 119.05, p < .001 |
 | Frequency of suicidal thoughts in the past year | 3.13 (1.59)n | 2.78 (1.5)n | 3.03 (1.57) | 1.83 (1.21) | H(2) = 101.35, p < .001 |
 | Suicide threat | 1.78 (.865) | 1.52 (.75) | 1.71 (.841) | 1.28 (.57) | H(2) = 52.9, p < .001 |
 | Likelihood of future suicide attempt | 2.85 (1.8) | 2.08 (1.71) | 2.65 (1.81) | 1.06 (1.25) | H(3) = 146.65, p < .001 |
 | Total SBQ-R score | 10.81 (4.05) | 9.04 (3.9) | 10.33 (4.08) | 6.28 (3.08) | - |
 |  > Psychiatric cut-off | 230 (76.7) | 48 (57.1) | 294 (71.4) | 183 (30.9) | X2(2) = 119.27 p < .001, φ = .42 |
SBQ-ASC visual aids | Yes | 117 (38) | 35 (31) | 152 (36.1) | 59 (22) | X2(2) = 17.21 p < .001, φ = .16 |
SBQ-ASC item 1: lifetime suicidality | Non-suicidal | 19 (6.17) | 10 (8.85) | 29 (6.89) | 81 (30.22) | Â |
 | Suicidal ideation—"brief passing thought" | 45 (14.61) | 40 (35.4) | 85 (20.19) | 82 (30.6) |  |
 | Suicidal ideation—"seriously thought about" | 41 (13.31) | 13 (11.5) | 54 (12.83) | 40 (14.93) |  |
 | Suicide plan | 90 (29.22) | 24 (21.24) | 114 (27.08) | 42 (15.67) |  |
 | Suicide attempt | 113 (36.69) | 26 (23.01) | 139 (33.02) | 23 (8.58) |  |
 | Mean item score | 2.76 (1.26) | 2.14 (1.35) | 2.59 (1.31) | 1.42 (1.3) | H(2) = 125.98, p < .001 |
Lifetime suicide attempt subgroup follow-up questions: | I had a plan that I carried out | 66 (58.41) | 12 (46.15) | 78 (56.12) | 10 (43.48) | X2(2) = 2.74, p = .254, φ = .131 |
 | I had no plan | 19 (16.81) | 1 (3.85) | 20 (14.39) | 3 (13.04) | X2(2) = 3, p = .223, φ = .136 |
 | I suddenly felt the urge to attempt to end my life (impulsivity) | 44 (38.94) | 12 (46.15) | 56 (40.29) | 12 (52.17) | X2(2) = 1.49, p = .474, φ = .096 |
 | I happened to have access to the means to end my life | 31 (27.43) | 9 (34.62) | 40 (28.78) | 5 (21.74) | X2(2) = 1.02, p = .6, φ = .08 |
SBQ-ASC item 2: frequency of suicidal thoughts in last 12Â months | Never | 90 (29.22) | 39 (34.51) | 129 (30.64) | 173 (64.55) | Â |
 | Less than once a month | 81 (26.3) | 36 (31.86) | 117 (27.79) | 64 (23.88) |  |
 | Once a month | 29 (9.42) | 16 (14.16) | 45 (10.69) | 13 (4.85) |  |
 | 2–3 times a month | 32 (10.39) | 8 (7.08) | 40 (9.5) | 8 (2.99) |  |
 | Once a week | 23 (7.47) | 4 (3.54) | 27 (6.41) | 4 (1.49) |  |
 | 2–6 times a week | 33 (10.71) | 9 (7.96) | 42 (9.98) | 5 (1.87) |  |
 | 1 or more times a day | 20 (6.49) | 1 (0.88) | 21 (4.99) | 1 (0.37) |  |
 | Mean item score | 1.99 (1.96)n | 1.41 (1.56)n | 1.83 (1.88) | .06 (1.09) | H(2) = 100.25, p < .001 |
SBQ-ASC item 3: duration of suicidal thoughts | N/A | 57 (18.51) | 34 (30.09) | 91 (21.62) | 146 (54.48) | Â |
 | Less than 5 min | 38 (12.34) | 22 (19.47) | 60 (14.25) | 46 (17.16) |  |
 | Less than 1 h | 71 (23.05) | 22 (19.47) | 93 (22.09) | 27 (10.07) |  |
 | 1–4 h | 73 (23.7) | 19 (16.81) | 92 (21.85) | 30 (11.19) |  |
 | 5–8 h | 29 (9.42) | 7 (6.19) | 36 (8.55) | 5 (1.87) |  |
 | More than 8 h | 40 (12.99) | 9 (7.96) | 49 (11.64) | 14 (5.22) |  |
 | Mean item score | 2.32 (1.6) | 1.73 (1.58) | 2.16 (1.61) | 1.04 (1.45) | H(2) = 95.7, p < .001 |
SBQ-ASC item 4: Likelihood of acting on suicidal thoughts | N/A | 43 (13.96) | 28 (24.78) | 71 (16.86) | 127 (47.39) | Â |
 | No chance at all | 49 (15.91) | 25 (22.12) | 74 (17.58) | 70 (26.12) |  |
 | Very unlikely | 95 (30.84) | 42 (37.17) | 137 (32.54) | 45 (16.79) |  |
 | Rather unlikely | 90 (29.22) | 17 (15.04) | 107 (25.42) | 25 (9.33) |  |
 | Rather likely | 27 (8.77) | 1 (0.88) | 28 (6.65) | 1 (0.37) |  |
 | Very likely | 4 (1.3) | 0 (0) | 4 (0.95) | 0 (0) |  |
 | Mean item score | 2.07 (1.21) | 1.45 (1.05) | 1.9 (1.2) | .89 (1.02) | H(2) = 128.38, p < .001 |
SBQ-ASC item 5: communication of suicidality to others | Suicidal ideation | 186 (60.39) | 50 (44.25) | 236 (56.06) | 82 (30.6) | Â |
 | Future suicide attempt | 82 (26.62) | 19 (16.81) | 101 (23.99) | 26 (9.7) |  |
 | Past suicide attempt | 110 (35.71) | 24 (21.24) | 134 (31.83) | 26 (9.7) |  |
 | Mean item score | 2.21 (2.25) | 1.42 (1.95) | 1.99 (2.2) | .79 (1.47) | H(2) = 78.68, p < .001 |
 | Overall communication of suicidality | 210 (68.2) | 57 (50.4) | 267 (63.4) | 92 (34.3) |  |
5b: Communicated suicidal intent subgroup: person(s) disclosed to | An acquaintance | 5 (2.6) | 4 (7.4) | 9 (3.6) | 3 (3.2) | - |
 | A friend | 73 (37.2) | 19 (35.2) | 92 (36.8) | 40 (42.6) | X2(2) = 1.03, p = .6, φ = .05 |
 | A family member | 75 (38.3) | 17 (31.5) | 92 (36.8) | 37 (39.4) | X2(2) = 1.02, p = .6, φ = .05 |
 | A health professional (e.g. General Practitioner, family doctor, Psychiatrist, Psychologist) | 138 (70.4) | 36 (63) | 172 (68.8) | 56 (62.3) | X2(2) = 3.65, p = .16, φ = .1 |
 | Other | 25 (12.8) | 8 (14.8) | 33 (13.2) | 15 (16) | X2(2) = .582, p = .75, φ = .04 |
5c: Non-disclosure subgroup: reasons | I had no one to tell | 22 (16.2) | 4 (7.1) | 26 (13.5) | 6 (9) | X2(2) = 3.95, p = .14, φ = .12 |
 | I chose not to | 38 (27.9) | 19 (33.9) | 57 (29.7) | 31 (46.3) | X2(2) = 6.72, p = .035, φ = .16 |
 | I was worried about the effect on others | 55 (40.4) | 22 (39.3) | 77 (40.1) | 28 (41.8) | X2(2) = 081, p = .96, φ = .02 |
 | I was worried about the consequences for myself | 39 (28.7) | 19 (33.9) | 58 (30.2) | 8 (11.9) | X2(2) = 9.3, p = .01, φ = .19 |
 | I wasn't sure how to express my thoughts | 39 (28.7) | 17 (30.4) | 56 (29.2) | 7 (10.4) | X2(2) = 9.51, p = .009, φ = .19 |
 | I was afraid to | 27 (19.9) | 8 (14.3) | 35 (18.2) | 5 (7.5) | X2(2) = 5.35, p = .07, φ = .14 |
 | I didn't consider telling anyone | 19 (14) | 15 (26.8) | 34 (17.7) | 18 (26.9) | X2(2) = 6.65, p = .036, φ = .16 |
 | Other (please specify): | 17 (12.5) | 7 (12.5) | 24 (12.5) | 4 (6) | X2(2) = 2.2, p = .33, φ = .09 |
SBQ-ASC item 6 (n = 602) | Lifetime NSSI | 160 (62.7) | 45 (46.4) | 205 (58.2) | 66 (26.4) | X2(2) = 67.46, p < .001, φ = .335 |
SBQ-ASC | Total score | 11.34 (6.39) | 8.15 (5.85) | 10.5 (6.4) | 4.75 (5.09) | U = 12,308.5, p < .001* |
 |  >  = SBQ-ASC autism cut-off | 138 (44.8) | 27 (23.9) | 165 (39.2) | 28 (10.4) | X2(2) = 85.02 p < .001, φ = .35 |