Background: Structural brain differences including decreased gray matt
er and increased cerebrospinal fluid volumes have been observed in the
brains of chronically ill patients with schizophrenia. We hypothesize
d that deficits in gray matter volume would be present in patients pre
senting with a first episode of nonaffective psychosis. Methods: We us
ed magnetic resonance imaging to compare the brains of 77 patients ass
essed as having a first episode of psychosis (meeting DSM-III-R criter
ia for schizophrenia, schizophreniform disorder, schizoaffective disor
der, delusional disorder, or psychotic disorder not otherwise specifie
d) with those of 61 healthy controls matched for age, sex, race, and p
arental socioeconomic status. Axial, dual-echo scans of the whole brai
n were segmented into gray matter, white matter, and cerebrospinal flu
id compartments using a computerized volumetric approach. These measur
es were corrected for the significant effects of intracranial volume a
nd age prior to performing between-group comparisons. Results: The fir
st episode psychosis group had significantly smaller gray matter volum
e (t[136] = -2.2; P = .03) and greater cerebrospinal fluid volume (t[1
36] = 2.5; P = .02) than normal controls. In the patient group, gray m
atter volumes were positively correlated with estimates of IQ but not
with age of onset, duration of illness, or measures of premorbid funct
ioning. Conclusions: Deficits in gray matter volume are present in pat
ients experiencing first episode nonaffective psychosis. The magnitude
of these differences is smaller than has been described in more chron
ically ill patients.