Table 1. Demographic and Clinical Characteristics of Self-Injurers and Controls at Baseline.
| Variablea | NSSI (n = 81) | Control (n = 86) | Statistical Testb | p | Effect Size |
|---|---|---|---|---|---|
| Demographics | |||||
|
| |||||
| Age: M (SD) | 19.06 (1.89) | 19.84 (2.11) | t = 2.50 | .014 | d = 0.39 |
| Gender: % female | 74.1% | 69.8% | χ2 = 0.20 | .655 | Φ = .05 |
| Ethnicity: % Caucasian | 51.9% | 37.2% | χ2 = 3.06 | .080 | Φ = .15 |
|
| |||||
| Axis I Psychopathology (# of participants who met full DSM-IV symptoms of disorder on PHQ) | |||||
|
| |||||
| Alcohol abuse | 28 | 12 | χ2 = 8.63 | .003 | Φ = .24 |
| Bulimia | 5 | 1 | χ2 = 1.75 | .186 | Φ = .13 |
| Generalized anxiety | 12 | 1 | χ2 = 9.01 | .003 | Φ = .25 |
| Major depression | 15 | 5 | χ2 = 5.24 | .022 | Φ = .20 |
|
| |||||
| Personality and Impulsivity Variables | |||||
|
| |||||
| MSI-BPD features: M (SD) | 6.31 (2.36) | 2.07 (2.26) | t = 11.75 | < .001 | d = 1.83 |
| (w/out self-injury item) | 5.31 (2.36) | 2.07 (2.26) | t = 8.98 | < .001 | d = 1.40 |
| Impulsivity: M (SD) | |||||
| Urgency | 11.04 (3.10) | 9.45 (2.98) | t = 3.37 | .001 | d = 0.52 |
| (lack of) Perseverance | 7.49 (2.84) | 7.20 (2.45) | t = 0.72 | .471 | d = 0.11 |
| (lack of) Premeditation | 8.44 (7.31) | 7.31 (2.52) | t = 2.72 | .007 | d = 0.42 |
| Sensation seeking | 11.51 (3.53) | 10.30 (3.38) | t = 2.25 | .026 | d = 0.35 |
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| |||||
| Implicit Associations (SI-IAT) | |||||
|
| |||||
| Identity version | −.09 (.31) | −.23 (.29) | t = 3.07 | .003 | d = 0.48 |
| Attitude version | −.33 (.28) | −.42 (.31) | t = 1.82 | .070 | d = 0.28 |
a
Detailed demographic, diagnostic (PHQ), and impulsivity (UPPS) differences between the self-injuring group and noninjuring control group at baseline were previously published in Glenn and Klonsky (2010).
b
Independent samples t-test degrees of freedom = 165. Pearson chi-square test degrees of freedom = 1, N = 167.