Screening for Generalized Anxiety Disorder in inpatient psychosomatic rehabilitation: pathological worry and the impact of depressive symptoms

OBJECTIVE Pathological worry is considered to be a defining feature for Generalized Anxiety Disorder (GAD). The Penn State Worry Questionnaire (PSWQ) is an instrument for assessing pathological worry. Two earlier studies demonstrated the suitability of the PSWQ as screening instrument for GAD in outpatient and non-clinical samples. This study examined the suitability of the PSWQ as a screening instrument for GAD in a German inpatient sample (N=237). Furthermore, a comparison of patients with GAD and patients with depression and other anxiety disorders regarding pathological worry and depression was carried out in a sub-sample of N=118 patients. METHOD Cut-off scores optimizing sensitivity, optimizing specificity and simultaneously optimizing both sensitivity and specificity were calculated for the PSWQ score by receiver operating characteristic analysis (ROC). Differences regarding pathological worry and depression measured by the PSWQ and the Beck Depression Inventory (BDI) across five diagnostic subgroups were examined by conducting one-way ANOVAs. The influence of depression on pathological worry was controlled by conducting an ANCOVA with BDI score as a covariate. RESULTS The ROC analysis showed an area under the curve of AUC=.67 (p=0.02) with only 54.4% of the patients correctly classified. Comparison of diagnostic subgroups showed that after controlling the influence of depression, differences referring to pathological worry between diagnostic subgroups no longer existed. CONCLUSIONS Contrary to the earlier results we found that the use of the PSWQ as a screening instrument for GAD at least in a sample of psychotherapy inpatients is not meaningful. Instead of that, the PSWQ can be used to discriminate high from low worriers in clinical samples. Thus, the instrument can be useful in establishing e.g. symptom-oriented group interventions as they are established in behavioural-medicine inpatient settings. Furthermore, our findings stress the influence of (comorbid) depressive symptoms on the process of worrying.