Adjustment disorder as proposed for ICD-11: Dimensionality and symptom differentiation

•This is the first study that empirically tests the new diagnostic concept of Adjustment Disorder for ICD-11 in a large-scale general population sample.•The findings support the new uni-faceted concept of Adjustment Disorder with core symptoms and additional feature clusters which supersedes the Adjustment Disorder multi-faceted concept from ICD-10 with different subtypes.•The Adjustment Disorder symptom list allows the assessment of Adjustment Disorder and its symptom severity (dimensional approach), according the new diagnostic concept.

Although Adjustment Disorder as a diagnostic category is widely used in clinical practice it is critically discussed that it has not been conceptualized as a category with unique symptoms. Hence, the conceptualization of Adjustment Disorder is subject to substantive change in ICD-11 including core symptoms and additional features in a uni-faceted concept. Adjustment Disorder was assessed with a self-rating instrument in a representative sample of the German general population (N=2512). Confirmatory factor analyses (CFA) were applied to test the dimensionality of symptoms according to the new diagnostic concept. Latent class analysis (LCA) was applied to test whether there are distinguishable subgroups with respect to symptomatology. 2.0% of the sample were diagnosed with Adjustment Disorder according to the new diagnostic algorithm. The proposed six factor model shows best fit with good reliability of the factors in the CFA compared to competing models. However the factors are highly correlated and not distinguishable. The LCA identified three latent classes, reflecting low, mild and moderate to severe symptoms. The findings support the uni-faceted concept of Adjustment Disorder as it is conceptualized in the new diagnostic concept in ICD-11 in a general population sample. This clearer diagnostic concept will inform research as well as clinical practice.