Differentiating bipolar disorder, schizophrenia diagnosis may improve psychosis outcomes

Differential diagnosis with bipolar disorder vs. schizophrenia appeared linked to certain positive outcomes among patients with first-episode psychosis, according to study results published in Journal of Clinical Psychiatry.

“An early distinction between bipolar disorder and nonaffective psychotic disorders has important treatment implications, as pharmacologic and psychological treatment regimens, as well as prognoses, differ between the groups,” Estela Salagre, MD, of the Bipolar and Depressive Disorders Unit at the University of Barcelona in Spain, and colleagues wrote. “Moreover, an early start of mood stabilizers in bipolar disorder is usually associated with a better response to treatment.”

Prior studies of first-episode psychosis samples largely focused on identifying factors associated with conversion to schizophrenia; however, less data are available regarding particular factors linked to the diagnostic shift to bipolar disorder.

In the current prospective, naturalistic study, Salagre and colleagues sought to identify predisposing factors and clinical features at baseline that may help predict diagnosis of bipolar disorder vs. schizophrenia among 335 individuals with first-episode psychosis. They compared baseline features between those with a final DSM-4 diagnosis of bipolar disorder and schizophrenia at 12 months of follow-up and used a binary logistic regression model to assess predictors of bipolar disorder diagnosis at follow-up.

Results showed 47 and 105 participants received a diagnosis of bipolar disorder and schizophrenia, respectively, at 12-month follow-up. Those with a final diagnosis of bipolar disorder had higher rates of family history of mood disorders, better baseline premorbid adjustment and psychosocial functioning, better cognitive flexibility, more manic symptoms, fewer negative symptoms and shorter duration of untreated diagnosis compared with those diagnosed with schizophrenia. According to results of the binary logistic regression model, lower Functional Assessment Short Test scores and fewer perseverative errors on the Wisconsin Card Sorting Test were significantly linked to diagnosis of bipolar disorder at follow-up.

“Further studies with larger sample sizes and longer follow-up periods are needed to confirm our results,” Salagre and colleagues wrote. “Even so, our findings support the notion that there are some baseline features that are easily measurable in a clinical setting and useful for identifying patients at high risk of a shift in diagnosis to bipolar disorder after FEP, hence making it possible to design early interventions tailored to these patients.”