062 - Intelligence Quotient Trajectories in Adolescents with Chromosome 22q11.2 Deletion Syndrome

Publication Number: 62.5373

Narueporn Likhitweerawong, University of California, Davis, School of Medicine, Sacramento, CA, United States; Nor Azyati Yusoff, University of California, Davis, School of Medicine, sacramento, CA, United States; Andrea Schneider, University of California, Davis, School of Medicine, Sacramento, CA, United States; Kathleen Angkustsiri, UC Davis MIND Institute, Sacramento, CA, United States

Background: Previous research indicates a decline in intelligence quotient (IQ) among adults with Chromosome 22q11.2 deletion syndrome (22q11.2DS). However, there is limited focus on IQ trajectories during adolescence, a critical transition period preceding the declines observed in adulthood.

Objective: This study aimed to evaluate the changes in IQ among adolescents with 22q11.2DS over time.

Design/Methods: Participants ages 12-18 were part of an observational longitudinal study of psychosis-proneness (2nd visit at approximately 2.5 years). Verbal comprehension index (VCI), perceptual reasoning index (PRI), and full-scale IQ (FSIQ), were assessed using the Wechsler Abbreviated Scale of Intelligence 2nd edition (WASI-II), Wechsler Intelligence Scale for Children 4th edition (WISC-IV), and/or Wechsler Adult Intelligence Scale 4th edition (WAIS-IV). Data from two time points were analyzed using descriptive statistics to perform annualized IQ changes individually over time, and paired t-test to evaluate within-group IQ changes.

Results: The study included 37 adolescents with 22q11.2DS, with a mean age of 15.3 years (SD = 2.1) at Time 1 and 17.9 years (SD = 2.2) at Time 2. On average, VCI and FSIQ scores showed significant declines from Time 1 to Time 2 (VCI: mean difference (MD) = -3.92, p < 0.01; FSIQ: MD = -2.62, p = 0.03), while PRI scores remained stable. Individual trajectories revealed fluctuations, with some participants experiencing pronounced declines in VCI and FSIQ that exceeded the magnitude of any gains (Fig. 1). The average annual decline was 1.42 points for VCI, 0.06 points for PRI, and 0.93 points for FSIQ. Notably, in approximately two-thirds of participants, VCI showed the most significant decline compared to PRI and FSIQ.

Conclusion(s): The findings suggest that VCI may be the first IQ parameter to decline in early adolescence in individuals with 22q11.2DS. A decline in verbal IQ is a known risk factor for psychosis in this population, underscoring the need for more frequent monitoring during this transitional period before adulthood. Future longitudinal studies with larger sample sizes and multiple time point measurements are recommended to further clarify IQ trajectories and inform clinical care.

Table 1. Baseline Characteristics


Table 2. IQ Changes from Time 1 to Time 2


Fig. 1. Annualized IQ Changes Individually.
(a) Annualized VCI Score Changes, almost two-thirds (62%) of the sample showed a decline in VCI from Time 1 to Time 2; (b) Annualized PRI Score Changes, 47% of the sample showed a decline in PRI from Time 1 to Time 2; (c) Annualized FSIQ Score Changes, 53% of the sample showed a decline in FSIQ from Time 1 to Time 2.