DUP may differentiate schizoaffective disorder from BD

By Mark Cowen, Senior medwireNews Reporter

Among individuals with a first episode of psychotic mania (FEPM), a longer duration of untreated psychosis (DUP) may differentiate patients with schizoaffective disorder from those with bipolar I disorder (BD I), study results suggest.

The researchers also found that among FEPM patients, those later diagnosed with schizoaffective disorder had worse illness severity, poorer psychosocial functioning, and were less likely to achieve remission than those later diagnosed with BD I.

However, Daniel Schöttle (University Medical Centre Hamburg-Eppendorf, Germany) and team comment that "despite these differences, both diagnostic groups need careful dimensional assessment and monitoring of symptoms and functioning in order to choose the right treatment."

The findings come from a study of 134 FEPM patients, aged 15-29 years, who attended the Early Psychosis Prevention and Intervention Centre in Melbourne, Australia. Of these patients, 36 received a final diagnosis of schizoaffective disorder and 98 a final diagnosis of BD I after a follow-up period of 18 months.

The groups were compared regarding pretreatment, baseline, and outcome variables.

The team found that schizoaffective disorder patients had a significantly longer DUP than BD I patients, at 31 versus 0 days, were more likely to have a history of traumatic events, at 44% versus 25%, and had greater baseline illness severity, as indicated by Clinical Global Impression - Severity of Illness Scale (CGI-S) scores of 6.1 versus 5.8.

A longer DUP was also associated with an increased likelihood for shifting from a diagnosis of BD at baseline to schizoaffective disorder at follow up.

Patients with schizoaffective disorder also stayed in treatment for significantly longer than BD I patients, at 73.0 versus 59.1 weeks, were more likely to be nonadherent to their medication, at 72% versus 51%, and, controlling for time in treatment and baseline scores, had greater illness severity and worse psychosocial functioning at discharge.

However, the researchers point out that, except for DUP, the effect sizes for these between-group differences were small.

They also found that, after controlling for time in treatment and baseline CGI-S scores, BD patients were significantly more likely to achieve remission of positive symptoms at discharge (odds ratio [OR]=4.9) and to be employed/occupied (OR=7.7) than schizoaffective disorder patients.

Schöttle and team conclude in Schizophrenia Research: "While long DUP may be an indicator of SAD [schizoaffective disorder] diagnosis or, specifically, of a later shift from BD to SAD, these diagnoses remain difficult to differentiate in patients presenting with a first-episode psychotic-manic syndrome."

They add: "In future studies, a more detailed assessment of life-time risk factors such as obstetric complications, delays in motor and language development, early cognitive deficits and other biological and psychosocial variables, may yield additional meaningful discriminators of SAD and BD."

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