A Meta-Analysis of Neuropsychological Functioning in Patients with Early Onset Schizophrenia and Pediatric Bipolar Disorder

Abstract

Despite the nosological distinction between bipolar disorder and schizophrenia, there is increasing evidence that these conditions share phenomenological characteristics. To examine the similarities in their patterns of cognitive impairment, we conducted a meta-analysis from 12 studies of Early Onset Schizophrenia (EOS) and 12 studies of Pediatric Bipolar Disorder (PBD). We found that individuals with PBD suffer from cognitive deficits (e.g., verbal learning and memory, processing speed, or executive control) that are milder but similar in nature to those of patients with EOS. Qualitative similarities between the neuropsychological profiles produced by these groups of patients might represent a “continuum of psychosis” or reflect some degree of genetic biological overlap.

Notes

¹References of articles included in the meta-analyses are listed in Appendix E.

Note: k = number of studies; EOS = number of Early Onset Schizophrenia participants; C = number of control participants; SMD = standardized mean difference; CI = Confidence Interval.

Note: k = number of studies; PBD = number of Pediatric Bipolar Disorder participants; C = number of control participants; SMD = standardized mean difference; CI = Confidence Interval.

^a Publication bias data are unavailable when fewer than three effect sizes are included in the analyses.

Note: ADHD = attention deficit/hyperactivity disorder.

^a Anxiety, Oppositional Defiant Disorder, or Conduct Disorder.

Note: FSIQ = Full Scale IQ; WASI = Wechsler Abbreviated Scale of Intelligence; WISC–III = Wechsler Intelligence Scale for Children; WAIS–III = Wechsler Adult Intelligence Scale; TONI–III = Test of Non-Verbal Intelligence; CPT = Continuous Performance Test; WCST = Wisconsin Card Sorting Test; TMT = Trail Making Test; D-KEFS = Delis-Kaplan Executive Function System; CANTAB = Cambridge Neuropsychological Automated Testing Battery; WMS–III = Wechsler Memory Scale–III; SCAP = Spatial Working Memory Capacity Task; AIM = Abstraction and Working Memory Test; TOMAL = Test of Memory and Learning; WRAML = Wide Range Assessment of Memory and Learning; CVLT-C = California Verbal Learning Test for Children and Adolescents; TAVEC = Test de Aprendizaje Verbal, Spanish version of CVLT; HVLT–R = Hopkins Verbal Learning Test-Revised; COWAT = Controlled Oral Word Association Test; RAN = Rapid Automatized Naming.

Note: For moderator data to be usable in regressions, the data must have been reported in sufficient detail and have shown variability across studies. EOS = Early Onset Schizophrenia; PBD = Pediatric Bipolar Disorder; SES = socioeconomic status.