ABSTRACT
Pediatric schizophrenia (Volkmar, 1996; Kumra, 2000) and pediatric bipolar disorder (Lewinsohn, Klein, and Seeley, 1995) are uncommon disorders with incidence rates of approximately 1%. Both are chronic illnesses associated with severe psychosocial morbidity (Werry, McClellan, and Chard, 1991; Andreasen, 1999; McClellan et al., 1999) and high utilization of mental health services (Murray and Lopez, 1996). It is often difficult to differentiate pediatric schizophrenia (PS) and pediatric bipolar disorder (PBD), especially in cases where symptoms of psychosis predominate. The distinction is important, however, given that PS and PBD respond to different psychopharmacological interventions, and PBD has a better long-term outcome (Werry et al., 1991; McClellan et al., 1999). Several studies comparing PS and PBD phenotypes indicate a strong bias against diagnosing bipolar disorder in youth (Joyce, 1984; Werry et al., 1991; Carlson, Fennig, and Bromet, 1994; Carlson, Bromet, and Sievers, 2000). This is illustrated by a major follow-up study in which earlier results (Kydd and Werry, 1982) were proclaimed invalid when about half of the schizophrenic cases were subsequently rediagnosed as bipolar disorder (Werry et al., 1991). In this study, 61 hospitalized children with initial diagnoses of schizophrenia, schizophreniform psychosis, bipolar disorder, schizoaffective disorder, or psychotic depression were evaluated. All those with follow-up diagnoses of schizophrenia had been correctly identified, but this was not the case in bipolar disorder, for which the initial diagnosis was frequently schizophrenia. This also explains the results of the initial study, which suggested a good outcome for schizophrenia in children under 16 years of age, associated with higher premorbid level of functioning, rapid onset of illness, and the presence of affective symptoms (Kydd and Werry, 1982). Furthermore, with the advent of recent data, there is another challenge to differentiate PBD from attention-deficit hyperactivity disorder (Wozniak et al., 1995; Biederman et al., 1996; Geller et al., 1998; Geller et al., in press). This will be briefly addressed in the “Recognition of Pediatric Bipolar Disorder” section. Apart from criteria that help to recognize and differentiate these disorders at a very young age, there is now evidence that even prodromal symptoms of psychosis can be identified (McGlashan, 1998; McGorry, 2000). It is uncertain, however, how accurately PS and PBD can be differentiated at this prodromal stage. This chapter reviews the critical issues in recognizing PS, PBD, and their prodromal symptoms, and how best to differentiate them.
