There is evidence that patients with schizophrenia benefit from standard cognitive behaviour therapy (CBT) only if active techniques are used ('full therapy'). By contrast, attending sessions but not proceeding beyond engagement and assessment strategies ('partial therapy'), or simply not attending sessions ('no therapy'), is not associated with better outcomes. The factors leading to full therapy are unknown. We hypothesized that patients' initial ideas about the nature and extent of their problems would predict use of CBT. A match between patients' views of their problems and the principles underlying treatment would lead to better outcomes.