Who carries the cost of interruptions? A qualitative study of doctors in UK hospital outpatient departments

Background Hospital outpatient departments (OPDs) deliver specialist care at scale, under close scrutiny over waiting times. Interruptions are common in this setting and are linked to error. Little is known about how they cause harm, for whom, and under what conditions. Methods Qualitative study using focus groups and interviews with 42 doctors working in UK National Health Service OPDs (19 sessions, September to November 2025). Participants were purposively sampled by clinical experience and self-reported patient complexity. Data were analysed using the Framework Method, informed by Cognitive Load Theory and Social Identity Theory, with independent double coding of 10% of transcripts (kappa = 0.97) and participant validation. Results We developed four themes. (1) Interruptions as a structural and increasingly ambiguous feature of clinical work. Interruptions were a normal part of clinical coordination, but new communication channels lacked shared norms about urgency, so each doctor had to judge what mattered. (2) The hidden cognitive cost of interruptions. The main cost came from returning to the interrupted task. This cost grew with complexity and was only partly offset by experience. (3) The social fabric of interruption burden. Transient teams weakened the norms that regulate interrupting, and approachability and hierarchy concentrated the burden on particular doctors. (4) The social amplification of cognitive burden. Understaffing multiplied cognitive costs. Doctors used familiarity and track record to decide which requests deserved attention, so concerns from junior or unfamiliar colleagues risked being discounted. Conclusions Interruptions are structural, and their impact depends on cognitive and social conditions. Reducing interruption frequency alone may miss the main risk. Interventions should support task resumption, protect capacity at busy times, rebuild shared communication norms and take account of the receiver's capacity when designing escalation.