“…The most commonly reported was perceived personal benefits, including the perception of therapeutic benefits, closer monitoring and access to new treatments [10, 20-22, 25-27, 29-37, 39-41]. Whilst altruism was the second most commonly reported factor, discussed in terms of benefitting science [10, 20, 29-31, 34, 36, 37, 39-41], helping others [10,20,21,26,27,30,31,34,35,37,40,41] or altruism more generally [22], this was sometimes linked to personal benefit [27,31,33]. For example, patients with depression were less likely to participate if it might risk their own mental health, despite wanting to help others [27].…”