We have come to rely on clinical trial data to provide the evidence base for treatments. But what do participants think about being involved in trials and could their perceptions have an affect on outcomes? In this study, we examine the perceptions of people with a diagnosis of depression who took part in a pharmacogenetic trial of anti-depressant medication.
The views of participants in trials have received some attention in general medicine. Ellis  carried out a systematic review of both doctors’ and patients’ attitudes to Randomised Controlled Trials in the field of cancer focusing in particular on randomisation and informed consent. Ellis argues that randomisation is a hurdle to recruitment as potential participants want choice over treatment and that comprehension of information is often low. The McArther group [2, 3] argue that participants in trials suffer from a ‘therapeutic misconception’ when they fail to distinguish clinical care from research and believe that participation in research comprises individualised treatment.
It is often argued that psychiatric patients have impaired decision making capacity which poses special hurdles in obtaining informed consent. This is particularly so in neurodegenerative conditions of the brain such as Alzheimer’s disease and there have been recent calls for clarification on the issues of proxy and surrogate consent . However, it has also been argued that other psychiatric diagnoses can lead to impaired decision making, including schizophrenia and depression. Nevertheless, in a series of studies, Roberts interviewed people with the condition most associated with impaired decision making, schizophrenia, and found no difference between their comprehension of the procedure of the trial and that of people without a psychiatric diagnosis (summarised in Dunn and Roberts ). We consider impaired capacity in depression in the Discussion section of this paper.
As far as we can ascertain, there have been no empirical studies of the perceptions of participants in pharmacogenetic studies in psychiatry although there have been conceptual reviews [6–8]. Issues of informed consent in mental health studies are unlikely to differ between pharmacogenetic and other studies as there remains a focus on capacity and vulnerable individuals. Informed consent entails understanding the purpose of a study and achieving it in pharmacogenetic studies may be more difficult as the concept is not easy to grasp. Indeed it is not easy for members of the general public or some policy makers to grasp .
For pharmacogenetics studies there is also another important consideration for participants and that is tissue banking and DNA profiling. Two conceptual reviews [6, 7] discuss issues such as the retention of samples for further research, the problem of whether or not results should be disclosed to participants, the interests of families and discrimination. In the present study, samples of blood were drawn, were anonymised and participants assured of confidentiality. However, they were aware that their blood samples would be used for research and stored centrally in the main study site.
To assess trial participants’ understanding of information during the informed consent process of GENDEP.
T o investigate the correspondence between the aims of scientists and the understanding of participants in GENDEP.
Context of the study
The study reported here was part of a wider investigation. GENDEP is a multi-disciplinary programme of research including a human study of the pharmacogenetics of anti-depressant medication. Other parts of the study included in vitro work and work on animal models. The human part was an open-label partially randomised trial. It took place in eight European countries  (for general background to GENDEP see: http://gendep.iop.kcl.ac.uk/background.php).
The funders of GENDEP, with strong support from the main study, required a component of the research to be its Ethical, Legal and Social Implications (ELSI). The participants’ perceptions work was carried out within the Service User Research Enterprise (SURE) who undertook focus groups with service users as well as the study reported here. Essentially, the ELSI research ‘piggy backed’ on the main human study.
The GENDEP main human study took place in nine sites (2 in Germany) and the ELSI sites were chosen to be representative of these. They were: London UK; Mannheim Germany; Aarhus Denmark and Poznan Poland.