Back space in regulations: legal frameworks of research with existing patient data

A subgroup of patients with severe mental illness (SMI) is underrepresented in scientific research, in part due to barriers around giving informed consent. This may lead to response bias and lack of knowledge about this group. Retrospective research with existing patient data is the only way to increase our knowledge for some patient groups. To make recommendations to exploit the possibility of retrospective research with existing patient data, taking into account applicable laws and regulations. After a review of relevant laws and regulations, recommendations are made. Factors that determine the possibilities for retrospective research are 1) whether the researcher works with directly traceable, pseudonymized or anonymized data; 2) whether there is a high risk of response bias when asking for informed consent; 3) whether information is collected within the treatment relationship. Depending on the situation, there are several alternatives to an informed consent procedure. Knowledge of the relevant regulations and collaboration with specialists in the field often makes retrospective research with existing data in those patients with SMI who cannot give informed consent possible.