Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Johnny Lee Matson


The primary focus of this investigation was to examine differences in depression, general psychopathology, and social skills among adolescents, and to identify the role of adaptive behavior between intelligence (I.Q.) and depression. One hundred adolescents, 13 through 17 years of age participated in this study. I.Q.s ranged between 40 to 130. Five levels of I.Q.s were studied (Above normal, Average, Borderline, Mild, Moderate). Three depression measures, the Child Depression Inventory (CDI), Reynolds Adolescent Depression Scale (RADS), Bellevue Index of Depression (BID), one social skills measure Matson Evaluation of Social Skills with Youngsters (MESSY), and one general psychopathology measure Psychopathology Instrument for Mentally Retarded Adults (PIMRA) were used. Multivariate Analysis of Variance (MANOVA) on the five dependent variables and five levels of I.Q.s, produced significant differences using Wilks Lambda criteria. All Univariate F's were significant. Linear discriminant function analysis produced two significant discriminant functions; depression and general psychopathology. In the first function the mild mentally handicapped group showed higher levels of depressive symptoms. In the second discriminant function the moderate mentally handicapped group showed higher levels of general psychopathology. The Above normal group evinced high social skills and low general psychopathology. The two discriminant functions combined accounted for 92% of the variance. The grouped cases had a correct classification of 45% (Above normal 75%, average 25%, borderline 25%, mild mentally handicapped 70%, moderate mentally handicapped 40%). Multivariate Analysis of Variance between normal and mentally handicapped groups showed that the two groups differed significantly on all dependent variables. The mentally handicapped group evinced low social skills, greater general psychopathology, and higher levels of depressive symptoms. The Above normal group showed high social skills, low depression, and low general psychopathology. Moderated regression between intellectual functioning (IQ), Adaptive behavior (AB), their product term (IQ x AB), and depressive symptoms (CDI, BID, RAD) was conducted. A significant interaction between the product term and depression on the Child Depression Inventory (CDI) was obtained. No significant moderating effect was found in the BID and RAD. Simple regression analysis showed that as the level of adaptive behavior increased the relationship between intelligence and depression weakened on the CDI. This supported the moderator hypothesis.