Theses and Dissertations

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Date of Award


Document Type

Dissertation - NSU Access Only

Degree Name

Doctor of Psychology (PhD)


Center for Psychological Studies

First Advisor

Wiley Mittenberg

Second Advisor

Ralph E. Cash

Third Advisor

Kristen Jones


anxiety, children, depression, Intelligence testing


Anxiety and depressive disorders are among the most common mental health problems diagnosed in children and adolescents, and numerous theories explaining why children experience these debilitating disorders have been proposed. Established diagnostic criteria that differentiate anxious and depressive symptomatology characterize both groups of disorders as having an adverse effect on the child's academic and social functioning. While research has sought to examine the cognitive effects these disorders have on adults, there is relatively limited research on the cognitive effects in children and adolescents. The available research literature examining effects of anxiety and depression on intelligence test performance is also inconclusive, and there are no studies that characterize the effects of these disorders on the Wechsler Intelligence Scale for Children - Fourth edition. The purpose of the study was to clarify the effects of childhood anxiety and depression on intelligence test scores using the current fourth edition of the Wechsler Intelligence Scale for Children. Participants were selected from an archival database from a neuropsychology clinic and separated into two groups according to clinical diagnosis. No significant differences were found between the children and adolescents diagnosed with clinical disorders and the standardization sample or in idiographic analyses with regard to the WISC-IV Full Scale IQ or the Working Memory Index. The Processing Speed Index was found to be significantly lower than the Verbal Comprehension Index in children diagnosed with major depressive disorder. This finding was not observed in the anxiety disorders group. Examination of component subtest score patterns showed that Coding and Symbol Search were reduced in the depression group. This finding is consistent with previous studies, which suggest that reduced performance on the Processing Speed Index may be attributed to psychomotor retardation in major depressive disorder.

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