Outcome measures We assessed the psychosocial consequences with the Consequences Of Screening–Breast Cancer, a condition-specific questionnaire that is psychometrically validated and encompasses 14 psychosocial dimensions.

Results Across all 14 psychosocial outcomes, women with false-positive results averagely reported higher psychosocial consequences compared with women with normal findings. Mean differences were statistically insignificant except for the existential values scale: 0.61 (95% CI (0.15 to 1.06), p=0.009). Additionally, women with false-positive results and women diagnosed with breast cancer were affected in a dose–response manner, where women diagnosed with breast cancer were more affected than women with false-positive results.

Conclusion Our study suggests that a false-positive mammogram is associated with increased psychosocial consequences 12–14 years after the screening. This study adds to the harms of mammography screening. The findings should be used to inform decision-making among the invited women and political and governmental decisions about mammography screening programmes.