title: Longitudinal trajectories of aberrant behavior in fragile X syndrome.
abstract: The Aberrant Behavior Checklist-Community (ABC-C; Aman et al., 1995) has been increasingly adopted as a primary tool for measuring behavioral change in clinical trials for individuals with fragile X syndrome (FXS). To our knowledge, however, no study has documented the longitudinal trajectory of aberrant behaviors in individuals with FXS using the ABC-C. As part of a larger longitudinal study, we examined scores obtained on the ABC-C subscales for 124 children and adolescents (64 males, 60 females) with FXS who had two or more assessments (average interval between assessments was approximately 4 years). Concomitant changes in age-equivalent scores on the Vineland Adaptive Behavior Scales (VABS) were also examined. As expected for an X-linked genetic disorder, males with FXS obtained significantly higher scores on all subscales of the ABC-C and significantly lower age-equivalent scores on the VABS than females with FXS. In both males and females with FXS, scores on the Irritability/Agitation and Hyperactivity/Noncompliance subscales of the ABC-C decreased significantly with age, with little to no change occurring over time on the Lethargy/Social Withdrawal, Stereotypic Behavior, and Inappropriate Speech subscales. The decrease in scores on the Hyperactivity/Noncompliance domain was significantly greater for males than for females. In both males and females, age-equivalent scores on the VABS increased significantly over this developmental period. These results establish a basis upon which to evaluate long-term outcomes from intervention-based research. However, longitudinal direct observational studies are needed to establish whether the severity of problem behavior actually decreases over time in this population.
authors.affiliation: Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, 401 Quarry Road, Stanford, CA 94305, United States. Electronic address: khustyi@stanford.edu.
authors.forename: Kristin M
authors.initials: KM
authors.lastname: Hustyi
authors.affiliation: Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, 401 Quarry Road, Stanford, CA 94305, United States. Electronic address: hallss@stanford.edu.
authors.forename: Scott S
authors.initials: SS
authors.lastname: Hall
authors.affiliation: Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, 401 Quarry Road, Stanford, CA 94305, United States. Electronic address: booil@stanford.edu.
authors.forename: Booil
authors.initials: B
authors.lastname: Jo
authors.affiliation: Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, 401 Quarry Road, Stanford, CA 94305, United States. Electronic address: aal@stanford.edu.
authors.forename: Amy A
authors.initials: AA
authors.lastname: Lightbody
authors.affiliation: Center for Interdisciplinary Brain Sciences Research, Department of Psychiatry and Behavioral Sciences, Stanford University, School of Medicine, 401 Quarry Road, Stanford, CA 94305, United States; Department of Radiology, Stanford University, School of Medicine, 300 Pasteur Drive, Stanford, CA 94305, United States; Department of Pediatrics, Stanford University, School of Medicine, 300 Pasteur Drive, Stanford CA 94305, United States. Electronic address: areiss1@stanford.edu.
authors.forename: Allan L
authors.initials: AL
authors.lastname: Reiss
mesh_terms: D000223:Adaptation, Psychological; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D005600:Fragile X Syndrome / Q000150:complications / Q000503:physiopathology* / Q000523:psychology; D006801:Humans; D007175:Impulsive Behavior; D007508:Irritable Mood; D053609:Lethargy / Q000209:etiology / Q000503:physiopathology*; D008137:Longitudinal Studies; D008297:Male; D010349:Patient Compliance; D012919:Social Behavior; D013064:Speech Disorders / Q000209:etiology / Q000503:physiopathology* / Q000523:psychology; D013239:Stereotyped Behavior; D055815:Young Adult
keywords: Aberrant behavior; Adaptive behavior; Fragile X syndrome; Longitudinal data