Background:
The present study aimed to validate the German version of the Short Defeat and Entrapment Scale (SDES).

Methods:
Validity and reliability were established in an online (N = 480), an outpatient (N = 277) and an inpatient sample (N = 296). Statistical analyses included confirmatory factor analyses (CFA) and group differences in defeat and entrapment.

Results:
For the online and the inpatient sample, the CFA indicated a two-factor solution, whereas for the outpatient sample both one- and two-factor solutions fitted the data equally well. Scale properties for the two-factor solution (defeat and entrapment subscale) were excellent. Thus, further analyses were based on this solution. For the online and the outpatient sample, suicidal ideators and suicide attempters scored significantly higher in defeat and entrapment than non-ideators and non-attempters.

Limitations:
Limiting factors of the study were the different measures across the samples and the cross-sectional design of the study.

Conclusion:
Though results were partly mixed, we found support for a two-factor solution of the instrument showing excellent psychometric properties in all three samples. The two-factor solution is further expected to have higher clinical utility than a one-factor solution. Suicidal ideators and suicide attempters in the online and outpatient sample showed higher scores in defeat and entrapment than non-ideators and non-attempters, emphasizing these two concepts as predictors for suicidal ideation. All in all, the present study supports the general validity and reliability of the SDES. However, future investigations based on prospective data are warranted.