We present a population-based, longitudinal study of all incident case
s (N = 538) of schizophrenia in the London Borough of Camberwell betwe
en 1964 and 1984. Cases were selected from the Camberwell Cumulative P
sychiatric Case Register, Case-notes were obtained, and further classi
fied using a computerized operational check list for rating psychotic
illness. Cases are not restricted to hospital discharges, as in previo
us studies, and account is taken of time at liberty to offend. In orde
r to test the hypothesis that schizophrenia makes an independent contr
ibution to criminality over other mental disorders, controls were chos
en to be representative of nonschizophrenic mental disorders matched f
or age, sex and period. The rate of conviction is increased in women w
ith schizophrenia compared to other mental disorders for most offence
categories (rate ratio = 3.3). In men overall rates do not differ (rat
e ratio = 1.03), although there is an interaction between gender, schi
zophrenia and ethnicity, with young black men with schizophrenia being
most at risk. The rate ratio for violent offences in men with schizop
hrenia is 3.8, confirming recent studies from Sweden, Subjects with sc
hizophrenia were more likely to acquire any criminal record than those
with other mental disorders. The rate of lifetime conviction was grea
ter in those with schizophrenia than either a sample of working-class
boys from the same area followed by Farrington & West, or National dat
a. The risk of first conviction is increased by schizophrenia, unemplo
yment, ethnic group, substance abuse and low social class, and decreas
ed by being employed, married, female and older age of onset. Adjustme
nt using survival analysis showed that schizophrenia made a small inde
pendent contribution to the risk of acquiring a criminal record (hazar
d ratio = 1.4), but gender, substance abuse, ethnicity and age of onse
t were more substantial. Previous criminality was the strongest indepe
ndent association of post-illness conviction, with schizophrenia only
a trend. Although subjects with schizophrenia were more likely to acqu
ire a criminal record, criminal careers began later and were shorter t
han those of the controls. The risk of criminality increased throughou
t the study period, but suggestions of a specific increase in those wi
th schizophrenia as a result of changes in community care were not con
firmed. These results confirm that women with schizophrenia are at inc
reased risk of acquiring a criminal record, but the effect in men is f
or violent convictions only. The strongest associations of criminal co
nviction remain those recognized in non-schizophrenic subjects.