Disfluencies such as self-repairs, filled pauses such as ‘um’and silent pauses are pervasive in dialogue, but there is no con-sensus in the literature as to whether they reflect internal pro-duction pressures, or interactive issues – or how their effectsare manifest in dialogue. It is well-known that patients withschizophrenia have problems with language and social cogni-tive skills, yet little research has investigated how these impactinteraction. We report a study on the disfluency behaviours ofpatients with schizophrenia and their interlocutors who wereunaware of the patient’s diagnosis, compared to healthy con-trol groups. Results show that patients use fewer self-repairsthan either their partners or controls and fewer filled pauses(‘er’, ‘um’) than controls. Furthermore, the presence of the pa-tient also affects patients’ partners, who use fewer filled pausesthan controls and more unfilled pauses than both patients andcontrols. This suggests that smooth coordination of turns isproblematic in patients’ dialogues