Until fairly recently, almost everyone who learned about, or carried out research into, personality disorders was taken in by the notion that personality disorder was a stable entity whose main characteristic was persistence, at least between the time of adolescence to middle age. We also suspected that those with these disorders, unless they received specific and necessarily powerful interventions, would remain continuously handicapped. Now it is clear that change in personality is possible, often rapidly so in some groups, and undergoes dynamic development from its genesis in childhood onward, and, though often achieving equilibrium, can never be said to be fixed in its manifestations. Longitudinal studies also show that personality abnormality identified early in life, whether temporary or longer-lasting, has a major influence on mental development and disorder generally, and, while it is impossible to say at present whether this influence is causal, it does suggest that early intervention could confer long-term benefits. An initiative such as that currently developed for early intervention in psychosis is at least as apt for personality disorder.