Recent research has only shown little evidence for a relationship between patient characteristics and treatment outcome. It is proposed that patients with a higher need of Mental Health Care due to...Show moreRecent research has only shown little evidence for a relationship between patient characteristics and treatment outcome. It is proposed that patients with a higher need of Mental Health Care due to higher psychopathologic complexity receive more treatment compared to others to reach a comparatively good treatment result. The treatment dose in more complex patients might therefore be significantly higher than in less complex patients. According to that, treatment dose should mediate the relationship between complexity and outcome. Thereby, the main purpose of this study is the investigation of a proposed mediation effect by treatment dose, operationalized as treatment duration in minutes and treatment length in days. Clinical Complexity was based on the degree of psychopathological severity and treatment outcome was measured with the self-report questionnaire Outcome Questionnaire-45. This investigation is based on a sample of patients in ambulatory treatment, who suffer from anxiety disorders, originated from the GGZ institution Arkin, an MHC provider in the Netherlands. Finally, no mediation effect has been shown and no evidence for an existent triadic relationship between complexity, outcome and treatment dose has been found. Besides, treatment duration correlated positively with complexity. Patients with higher complexity also tend to have a less favorable treatment outcome compared with patients of lower complexity. The results of this study should be interpreted and dealt with caution due to potential threats to internal and external validity. In future research alternative complexity and treatment dose indicators need further investigation to assess the prognostic value of patient characteristics for treatment outcome.Show less