The possibility that psychological response within a few weeks of a breast cancer diagnosis can influence the outcome of the disease is a contentious issue. Psychological response, including helplessness/hopelessness, fighting spirit and depression was assessed in early-stage breast cancer patients between 1 and 3 months post-diagnosis, in order to ascertain effect on cancer prognosis. Patients were followed up for a period of 10 years in order to clarify the effect of psychological response on disease outcome. After 10 years, there is a continuing effect of helplessness/hopelessness on disease-free survival (adjusted hazard ratio (HR) 1.53, 95% confidence interval (CI) 1.11-2.11) but not of depression (adjusted HR for overall survival for 'cases' 2.43, 95% CI 0.97-6.10). Longer follow-up also indicates that a high fighting spirit confers no survival advantage. The results showed that, in patients who were disease-free at 5 years, their baseline helpless/hopeless response still exerted a significant effect on disease-free survival beyond 5 (and up to 10) years. The effect is therefore maintained for up to 10 years of follow-up. Clinicians may wish to screen for helplessness around the time of diagnosis in order to target psychological care resources. Further large studies, with similarly prolonged follow-up, are needed to replicate this effect and clarify its mechanism of action.