Length of outpatient treatment affected by extraversion: Still waters run long

It has often been shown that in outpatient settings, about half of the treatments are terminated after only a few sessions. The present study sought to investigate the contribution of personality traits to length of treatment in a behaviour therapy-oriented outpatient treatment setting. All patients admitted during a 1 yr period filled out a personality questionnaire before the start of treatment, and were followed for at least 1 yr. It was found that Introverts stayed much longer in therapy and got more treatment sessions than Extraverts. Level of Neuroticism did not influence length of treatment. Low Extraversion scores may be a reflection of more severe and enduring (trait-like) psychiatric symptomatology. Also, Introverts may need more time to engage in a therapeutic relationship.