Evidence-based psychiatry (EBP) is an important and useful method. However, it covers only a limited range of clinical problems psychiatrists and psychotherapists encounter in daily work. This is due to some particularities of psychiatric diagnoses and therapeutic practice. (i) The validity of psychiatric diagnoses is limited. EBP is entirely depending on diagnoses, so one of its core assumptions is of doubtful applicability in the field of psychiatry and psychotherapy. (ii) Effects of complexity are more obvious in psychiatric and psychotherapeutic cases. Owing to its conceptual bases, EBP cannot sufficiently consider such effects and is therefore of limited usefulness addressing particular problems in fluctuating or symptomatically shifting diseases. (iii) EBP's strong focusing on decision making does not reflect appropriately the clinical reality of psychiatrists and psychotherapists. Diagnostic and therapeutic procedures are in fact more iterative, and decisions are constantly re-evaluated. EBP is not helpful to adjust this type of individual approach, which is needed to treat individual patients.