Older clinical authors used to think that epilepsy should always be
considered as a possible diagnosis when a violent crime had occurred,
especially those crimes which took place in a sort of "blind
fury". Old legal medicine texts described criminals with an
"epileptoid constitution", which was considered a sort of a
mental trait predisposing them to violent crime.
Subsequent surveys didn’t bear out this proposition. One
Scandinavian study of nearly a thousand epileptics found no excess of
criminal activity if there existed no psychiatric disorder. More recent
studies of the prevalence of epilepsy in prisons in the United Kingdom,
found epileptics to be slightly more represented, but this can only
establish that they are more likely to be sent to prison, not that they
are more likely to be criminal (besides, these results were not confirmed
in similar studies done in Italy and France).
In any case, their criminal offences are not likely to be more violent
than those of other prisoners. Thus, any link between dangerousness and
epilepsy is probably due to its complications or associations rather than
to the attacks themselves and this connection should never be made as a
general rule.