Background. Past studies have found inconsistent evidence
that substance use disorders are related
to earlier onset of schizophrenia or more severe symptoms. This study examines
severity of current substance use disorders and onset of psychotic illness
in a multi-facility sample.
Methods. Data are from the Suffolk County Mental Health Project,
an epidemiological study of
first admission psychosis. The SCID and instruments measuring symptomatology,
background characteristics were administered. Respondents were stratified
into three groups: (a) no
life-time substance diagnosis; (b) in remission or reporting current
mild use at admission; and (c)
current moderate–severe substance abuse at admission.
Results. Using the SCID severity rating, 17·4% of males
and 6·2% of the females had moderate or
severe current substance abuse, while 41·5% of males and 68·2%
of females had no lifetime
substance diagnosis. In almost all cases categorized as moderate–severe,
the substance diagnosis
predated onset of psychosis. Females categorized as moderate–severe
had an earlier age of onset of
psychosis than did females in the other groups. There were only slight
differences in symptom
severity among the groups but more marked antisocial behaviour in the moderate–severe
Variables discriminating the moderate–severe from non-abuse groups
were BPRS thought
disturbance, adult anti-social behaviour and current cigarette smoking
for males and adult antisocial
behaviour and child–teen antisocial behaviour for females.
Conclusions. Severity of substance abuse does not appear to
be a pivotal correlate of the early
features of psychotic illness.