Scientific evidence in the field of psychiatry is mainly derived from group-based
(“nomothetic”) studies that yield group-aggregated results, while often the need is to answer
questions that apply to individuals. Particularly in the presence of great inter-individual
differences and temporal complexities, information at the individual-person level may be
valuable for personalized treatment decisions, individual predictions and diagnostics. The
single-subject study design can be used to make inferences about individual persons. Yet …