[The randomization problem in psychotherapy studies].
In a research project comparing inpatient and outpatient psychotherapeutic treatment for patients suffering from anxiety disorders, 132 subjects were allocated to both treatments by means of randomisation. Because of the patients' voluntary agreement or refusal of the proposed treatment, the subsamples are markedly affected in their homogeneity. It seems that more disturbed patients agreed to inpatient psychotherapy, whereas less disturbed patients refused that form of treatment. Bias toward or against a given form of treatment turned out to be the most potent predictor in multivariate analysis. The influence of this distortion of the samples is discussed with regard to the generalisation of the results. Proposed countermeasures have their shortcomings, and in the end it seems that randomisation should be avoided in psychotherapeutic research.
Krauthauser
H
H
Klinik für Psychosomatische Medizin und Psychotherapie, Jöhannes Gutenberg-Universität Mainz.
Bassler
M
M
D000328:Adult; D000553:Ambulatory Care; D001008:Anxiety Disorders / Q000523:psychology / Q000628:therapy*; D015982:Bias; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010342:Patient Acceptance of Health Care; D010343:Patient Admission; D011613:Psychotherapy; D016896:Treatment Outcome