A young man has multiple convictions for theft and assault, all of which occurred exclusively during periods of heavy alcohol and drug use, with no antisocial behaviour at all during his extended periods of sobriety. Before revealing the answer: does this amount to dissocial personality disorder?

Not on this evidence. Dissocial personality disorder must be distinguished from secondary criminal behaviour caused by alcohol or drug misuse alone, which is absent when the substance misuse is absent — and here the antisocial behaviour is confined entirely to periods of heavy use, with none during his sober periods. This pattern points toward substance-related behaviour rather than an enduring personality disorder, since a genuine personality disorder would be expected to show its pattern across contexts, not only when a specific substance is involved. Most violent people, it is worth remembering, do not in fact have dissocial personality disorder, so this history alone is not sufficient evidence for the diagnosis.