108 Schizophrenia Spectrum and Other Psychotic Disorders
schizoaffective disorder is higher  in females than in males, mainly due to an increased in-
cidence of the depressive type among females.
Development and Course
The typical age at onset of schizoaffective di sorder is early adulthood, although onset can
occur anywhere from adolescence to late in lif e. A significant number of individuals diag-
nosed with another psychotic illness initially will receive the diagnosis schizoaffective dis-
order later when the pattern of mood epis odes has become more apparent. With the
current diagnostic Criterion C, it is expected  that the diagnosis for some individuals will
convert from schizoaffective d isorder to another disorder as mood symptoms become less
prominent. The prognosis for schizoaffective di sorder is somewhat better than the prog-
nosis for schizophrenia but worse than the prognosis for mood disorders. 
Schizoaffective disorder may occur in a variety of temporal patterns. The following is
a typical pattern: An individual may have pronounced auditory hallucinations and per-
secutory delusions for 2 months  before the onset of a prom inent major depressive episode.
The psychotic symptoms and the full major depr essive episode are then present for 3 months.
Then, the individual recovers completely fr om the major depressive episode, but the psy-
chotic symptoms persist for another month be fore they too disappear. During this period
of illness, the individual’s symptoms concurre ntly met criteria for a major depressive ep-
isode and Criterion A for schizophrenia, and during this same period of illness, auditory
hallucinations and delusions were present both before and after the depressive phase. The
total period of illness lasted for about 6 mo nths, with psychotic sy mptoms alone present
during the initial 2 months, both depressive  and psychotic symptoms present during the