Sedation and mental clouding are of concern to people on antipsychotic medication and are implicated in social withdrawal but their severity may be underestimated by psychiatrists. Existing studies of communication about adverse effects of medication are based on reports made by doctors or patients. This study is based on audiotapes of 92 outpatient consultations in two UK mental health trusts involving nine consultant psychiatrists where antipsychotic medication was discussed. When interviewed, these doctors and their colleagues had expressed a commitment to 'patient-centred' practice as well as recording concerns about the difficulties involved in the discussion of medication side effects. The study focuses on the ways in which sedation and mental clouding are presented and engaged with. Analysis of audiotape transcripts showed that patients raise these issues more often than doctors, contrasting with other adverse effects (such as blood changes) where doctors are more frequently the initiators of discussion. Sleepiness is sometimes presented by both patients and doctors as a part of normal experience and therefore to be welcomed. When presented as troublesome, patients' reports were sometimes met by doctors offering no response, changing the subject, or disagreeing with the patient's interpretation of the experience. Equally, there were some attempts by doctors to engage with patients' troubles and seek solutions. These could be unsuccessful where they involved challenges to the patients' medication-taking rationale, or more successful where they involved sympathetic and supportive listening. We speculate that the capacity to avoid addressing these problems is linked to the informal conversational style of these consultations, which means that concerns raised by one party can remain unaddressed without offending conversational norms. Doctors in these consultations are able to exercise considerable discretion over whether to define reports of sedation and mental clouding as medication-related problems.