This study assessed the perspectives of adults who had acute nonorganic psychiatric disorders and were admitted in a private, not for- profit medical college hospital, and also of their key relatives, on randomised controlled trials (RCTs). Structured questionnaires and audio-recorded interviews were used for the purpose. We explored their willingness and motivation to participate in two hypothetical RCTs with different risks and burdens. The transcripts of the interviews were analysed using the principles of grounded theory and framework analysis. Of the 24 consenting participants (12 patient and key-relative dyads), the 20 who completed the interviews had largely positive attitudes towards research and RCTs. However, 50% of those interviewed declined to participate in either of the hypothetical RCTs. The refusal to participate seemed to be influenced by a lack of education; forgetfulness, which impeded the process of making informed decisions; unfavourable benefit–risk–burden ratios; practical difficulties; dependence on treating doctors and relatives for decision-making; and the wish to exercise one's choice regarding treatment options. The factors that motivated the patients and relatives were trust in doctors and organisations, altruism, expectation of personal benefits and favourable risk–benefit ratios. These observations indicate that while the respondents in this study valued research, they were discerning about whether or not to participate in the trials; their decision-making was influenced by individualised assessments of risks and burdens and pragmatic considerations, rather than only by the benefits they would obtain.