Research has demonstrated that short term psychological interventions improve the quality of life of cancer patients. However, there is much less evidence for the efficacy of longer term interventions. We report the psychometric results from a randomized clinical trial (n=66) assessing the effects of an 8 month, weekly psychological intervention on 30 metastatic breast cancer patients. Subjects were assessed at baseline, 4, 8 and 14 months for mood, quality of life and adjustment to cancer. Results demonstrated little psychometric difference between the control (n=36) and intervention groups over this length of time, in spite of the fact that when the intervention subjects attended a weekend of support and training in coping skills, the usual significant, short term changes were observed. In the long term intervention, subjects did experience more anxious preoccupation and less helplessness than the controls but no recorded improvements in mood or quality of life. However, profound clinical changes were observed by the therapists, similar to those noted by Spiegel et al. (1981). We conclude that many of the psychological changes made by subjects in longer term interventions may elude conventional psychometric assessment. Further research, of a rigorous qualitative nature, is required to develop a clearer understanding of the experience of living and eventually dying of cancer within the context of a long term intervention. Copyright © 1999 John Wiley & Sons, Ltd.