Effects of adult inpatient group psychotherapy on attachment characteristics: an observational study comparing routine care to an untreated comparison group

This study investigated the changes in attachment characteristics of patients undergoing inpatient group psychotherapy in routine care. We collected data from 265 consecutively recruited patients and 260 non-clinical control persons using self-report measures of attachment, depression, and socio-demographic characteristics. The effects of treatment on patients were analyzed using propensity score techniques (propensity strata and logit-transformed propensity scores) in combination with a generalized analysis of covariance. A moderate increase of attachment security was found which could be attributed to a decrease both in attachment anxiety and avoidance. Pre-post improvements in attachment with regard to romantic partnerships were stable after a 1-year follow-up. Furthermore, we found significant treatment-covariate interactions indicating that subjects with particularly high treatment propensities (propensities were highly correlated with depression and attachment anxiety) improved the most in terms of attachment security. Our results are encouraging for psychotherapeutic practice in that they provide evidence that long-term attachment improvements can be reached via psychotherapy. Our results will also provide a sound basis for future studies in the field of clinical attachment research, e.g., studies examining whether improved attachment security is correlated to symptom improvements in different psychological disorders.