Better brain biology will deliver better medicines

A broken brain, hidden inside a skull, is harder to diagnose than a broken leg. The fact that there is somebody inside the skull to tell doctors how they feel might seem to offer a way round this. But the feelings patients describe are not easily mapped on to the brain. Definitions of mental diseases are vague. “Major depressive disorder and generalised anxiety have an 80% overlap in disease definitions,” says Daniel Karlin, the chief medical officer of MindMed, a biotech firm.