Social Skills Deficits in Learning Disabilities: The Psychiatric Comorbity Hypothesis

Abstract

The hypothesis that social skills deficits in learning disabilities may reflect the comorbidity of learning disabilities with psychiatric diagnoses is partially supported by prevalence rates of learning disabilities within samples of individuals with attention deficit hyperactivity disorder (ADHD) and depressive or dysthymic disorder. The maladaptive social skills patterns of children with specific subtypes of learning disabilities appear to mimic the symptom patterns of children with ADHD, depression or dysthymia, thus providing additional support for the psychiatric comorbidity hypothesis. This article includes a discussion of the implications of a psychiatric comorbidity hypothesis for increased special education support, further delineation of subtypes of learning disabilities, therapeutic, psychological or psychopharmacologic treatment, and collaborative efforts between professionals in mental health and learning disabilities.

Concern about the social functioning and psychological adjustment of children and adolescents with learning disabilities is prevalent among parents, professionals and researchers (La Greca & Vaughn, 1992). Although social skills deficits have been established to some degree in the majority of studies on individuals with learning disabilities, and despite little doubt that social or behavioral difficulties exist in this population, social skills deficits do not appear to be exclusively or invariably characteristic of children or adolescents with learning disabilities. Not only are there studies in which children with learning disabilities and children without disabilities do not differ (Cartledge, Stupay, & Kaczala, 1986), there are also studies in which the social skills deficits of children with learning disabilities do not differ from those of children with behavioral or other disorders (Schumaker, Hazel, Sherman, & Sheldon, 1982).

Recent meta-analysis also suggests that social skill deficits are not invariably characteristic of children with learning disabilities (Kavale & Forness. 1996). This meta-analysis makes it clear that most studies on social skills deficits of children with learning disabilities do not provide sufficient data to determine the prevalence of social skills deficits within this population. Instead, most studies present mean differences on social skills ratings between samples with and samples without learning disabilities.

Just as there are no clear prevalence data on social skills deficits in children with learning disabilities, the exact nature of the relationship between social skills deficits and learning disabilities is a matter of speculation. The limited research literature on social skills deficits in learning disabilities focuses on five hypotheses that attempt to explain the nature of social skills deficits in learning disabilities (Forness & Kavale, 1991).

First, social skills deficits are posited to be a consequence of the neurologic dysfunction presumed to underlie a child’s or adolescent’s academic skills deficits (Boucher, 1986: Bryan, 1982; Oliva & La Greca, 1988; Renshaw & Asher, 1983; Wiener, 1980). Second, the academic and learning problems of a youngster with a learning disability result in poor-self concept, rejection or isolation from peers, or other obstacles to the development of social skills (Osman, 1987). Third, children or adolescents with learning disabilities fail to acquire or perform social skills because of limited environmental opportunity to learn such skills, to perform such skills, and to be reinforced for them (Gresham, 1988). Fourth, social skills deficits are related to a child’s or adolescent’s familial social support system whose effectiveness is reduced by the stress of dealing with or adapting to a youngster with a special need (Amerikaner & Omizo. 1984: Kronick. 1978: Wilchesky & Reynolds, 1986). Fifth, differences in social skills deficits between learning disabled and nonlearning disabled samples may occur because of the comorbidity of certain children in learning disabled samples who have other diagnoses such as attention deficit hyperactivity disorder (ADHD) and depression. This last hypothesis (Forness & Kavale, 1991) has not been widely explored, however.

This article explores the hypothesis that social skills deficits among children with learning disabilities are associated with high rates of undetected psychiatric diagnoses. Indeed, social skills problems also occur in children and adolescents who experience hyperactivity and depression or related disorders (Cantwell & Carlson, 1983: Henker & Whalen, 1989; Kovacs, 1989; Prior & Griffin, 1985). Given that hyperactivity and depression co-occur to a great extent with learning disabilities, the co-occurrence of such disorders may account for the substantial social skills difficulties in children and adolescents with learning disabilities.

In order to explore the psychiatric comorbidity hypothesis, information on ADHD and depression or dysthymia and each disorder’s co-occurrence with learning disabilities will be briefly reviewed. Second, data will be presented from a study in which a number of children are characterized by a combination of a learning disability and a related behavioral difficulty or depression. The discussion then turns to learning disabilities subtypes and possible links between types of disabilities and types of behavioral or emotional disorders. Last, we consider the implications of the evidence supporting the hypothesis that social skills deficits may reflect the comorbidity of learning disabilities with other diagnoses such as ADHD and depression.

Learning disabilities and ADHD can coexist with other emotional or behavioral disorders. For example, comorbidity of learning disabilities within samples of individuals with other disorders such as conduct disorder, ADHD, and depressive or dysthymic disorder ranges from 10% to 25% (American Psychiatric Association, 1994). Notably, the validity of studies of comorbidity of learning disorders with other is compromised by the finding that the other disorders themselves (e.g., ADHD and depressive disorders) also frequently coexist (Bird, Gould, & Staghenzza, 1993).

Whether learning disorders predispose a person to other disorders. whether other disorders lead to underachievement and, thus, to learning disorders, or whether a common risk factor leads to concurrent development of learning disorders and other disorders is a matter of debate. As a result, the origin of social skills deficits sometimes seen in individuals with learning disabilities is unclear. These social skills deficits may accompany learning disorders or may result from other disorders that co-occur with learning disabilities. Given the complexities of the issue, a general understanding of ADHD, depression, and their co-occurrence with learning disabilities is essential when considering whether social skills deficits in the population with learning disabilities stem from the comorbidity of learning disabilities with other diagnoses. Thus, ADHD and depression are defined and their prevalence rates are reported in the sections that follow.

According to DSM IV (American Psychiatric Association, 1994), ADHD describes a syndrome with the following principal symptoms: inattention, impulsivity, and hyperactivity. According to the diagnostic scheme, certain core symptoms of inattention and/or of hyperactivity and impulsivity are required to qualify for ADHD classification. Recent estimates of the prevalence of ADHD are 3% to 5% of the childhood population (Barkley, 1990; Szatmari, Offord, & Boyle, 1989).

In a systematic search of the psychiatric and psychological literature for empirical studies dealing with the comorbidity of ADHD with learning disabilities, Biederman, Newcorn, and Sprich (1991) found that the reported degree of overlap ranged from a low of 10% to a high of 92%. In all likelihood, this variability results from differences in selection criteria, sampling and measurement variations, as well as discrepant definitions of learning disabilities and ADHD in various studies. Recent investigations suggest that fewer than 10% of samples of children with ADHD qualify as learning disabled when strict learning disability discrepancy formulae are used (Forness, Youpa, Hanna, Cantwell, & Swanson,1992; Shaywitz & Shaywitz, 1988), but this figure may approach 20% when less restrictive diagnostic criteria are used.

If an individual has a learning disability and ADHD, the consequent hyperactivity, distractibility and/or impulsivity may interfere with school, peer interaction and family life (Silver, 1989). In a review of the school performance of children with ADHD, Biederman et al. (1991) highlighted the following findings: (a) children with ADHD perform more poorly than controls in school in terms of grade repetitions, grades in academic subjects, placement in special classes and need for tutoring (Edelbrock, Costello & Kessler, 1984; Lahey, Strauss, & Frame, 1984; Silver, 1981; Weiss, Hechtman, Perlman, Hopkins, & Wener, 1979); (b) youngsters with ADHD perform more poorly than controls on standard measures of intelligence and achievement (Campbell & Werry, 1986); and (c) the academic and learning problems of children with ADHD continue into adolescence and are related to chronic underachievement and school failure (Gittelman, Mannuzza, Shenker, & Bonagura, 1985; Weiss. Milroy, & Perlman, 1985). In regard to social interaction, problems with family, members and peers have been documented (Barkley, 1990; Milich & Landau, 1982; Pelharn & Bender, 1982).

Thus, there is considerable evidence of a small but significant sample of children with learning disabilities whose social skills deficits may result not from learning disabilities per se, but from ADHD. The number of children in this population is not entirely clear, but a recent meta-analysis suggested that hyperactivity as assessed by teachers of children with learning disabilities was a significant problem (Kavale & Forness, 1996).

Learning disabilities and depression

A scheme depicting the general diagnostic features of major depression and dysthymia is presented in Table 1.

Forness (1988) reviewed 15 epidemiologic studies on childhood depression. While the reviewed studies relied on more objective and replicable measures, considerable variability was found in the percent of samples who were depressed, often because of diagnostic criteria and instrumentation. Maag and Forness (1991) found that depression is prevalent in at least 2% of the child population. Prevalence of depression in the normal population tends to increase with age. Consequently, prevalence in adolescents may be closer to 10% or higher.

Special populations tend to demonstrate an even higher prevalence rate. For instance, Wright-Strawderman and Watson (1992) investigated the prevalence of depressive symptoms in a sample of 53 public school elementary children aged 8 through 11 identified as learning disabled by state standards. They found that 35.9% scored in the depressed range on the Children’s Depression Inventory (CDI) (Kovacs & Beck, 1977). This prevalence figure is similar to earlier studies about depression in samples with learning disabilities. For example, Goldstein, Paul and Sanfilippo-Cohn (1985) found 26% of children aged 5 through 12 to be above the cutoff score for depression on the CDI. Given that the link between depression and suicide is another critical concern (Guetzloe, 1985), it is notable that 11% of the children in the Wright-Strawderman and Watson study indicated they wanted to kill themselves. The high rate of learning disabilities found among children who commit suicide is reflected in a study that found that in a three-year period, 50% of the children who had committed suicide in Los Angeles County had been identified as learning disabled (Peck, 1985).

Studies on the course of depression provide information on depression and the school and psychosocial functioning of youth with learning disabilities. Kovacs and her colleagues (1984a, 1985b) studied the course of depression in 64 children. In her sample, 65% had a major depressive disorder, 43% had dysthymia, and 17% had adjustment disorder with depressed mood. Overlap in these percentages reflects the fact that major depression was superimposed on dysthymia. In the depressed groups, 32% were reported to have failed a grade, 31% were in remedial or special education. and 26% had been suspended from school. In turn, Puig-Antich et al. (1985a, 1985b) investigated the nature of psychosocial functioning of children who met criteria for major depressive episodes. A total of 52 children (65% male; ages 6 to 12 years) were matched with two control groups; one group consisted of nonpsychotic, nondepressed child psychiatric patients- the other contained normal children. Compared with either of the control groups, depressed children were less communicative and less able to maintain peer relationships.

As with ADHD, there is also evidence that depression is a significant comorbid diagnosis in children with learning disabilities. Note as well from Table 1 that certain cognitive symptoms characteristic of children with depression may overlap those of children with learning disabilities.

Learning disabilities, depression and ADHD

The notion that other preexisting or concurrent disorders may be expected in learning disabilities is confirmed by the results of a study of the school placement of psychiatric patients (Forness, 1988). Data were gathered over the course of a year on a select group of children at the UCLA Neuro Psychiatric Institute (NPI). These children were diagnosed with dysthymia or depression by advanced child psychiatry residents supervised by faculty in the UCLA Mental Retardation and Child Program. Diagnoses of learning disabilities, in turn, were made by experienced school psychologists. Because considerable comorbidity is likely in children referred for evaluation or treatment, a systematic procedure to group cases by principal and secondary Axis I diagnoses and by principal Axis II diagnosis was used as previously developed by Sinclair, Forness, and Alexson (1985). A total of 111 subjects of elementary and junior high ages were seen in the child outpatient clinic at UCLA. Data on these subjects are depicted in Table 2.

The children depicted in Table 2 comprise three groups: (a) those with only a single Axis I diagnosis of affective disorder (major depression or dysthymia), (b) those with other Axis I diagnoses in addition to affective disorder (usually conduct disorder or ADHD), and (c) those with Axis II diagnoses of learning disorders in addition to affective disorder. A few of the children in the third group also had some conduct disorder or ADHD.

As shown in Table 2, only about two in five subjects had a diagnosis of depression or dysthymia alone. In turn, about one in three had such a diagnosis accompanied by a secondary diagnosis, typically ADHD or conduct disorder. The remaining subjects demonstrated a high degree of comorbidity as well, but were differentiated from the first two groups by having a learning disability diagnosis in addition to their depressive or disruptive behavior disorder.

Outpatient evaluations were completed and the children were followed to determine their school placement. In contrast to the first and second groups, students in the third group were much more often found to be eligible for special education, typically a resource room placement.

Resource room placement resulted either because the children qualified in the learning disabled (LD) rather than the severely emotionally disturbed (SED) category, or because their educational performance was so obviously impaired that they received services primarily for their academic rather than their behavioral or emotional difficulties even though they qualified in the SED category.

In short, comorbidity with conduct disorders or ADHD seemed to produce a higher rate of special education services than the single disorder. However, “trimorbidity,” that is, the addition of a learning disability diagnosis seemed the surest guarantee of such services.

Examination of subjects with ADHD from another UCLA child outpatient sample (Sinclair et al., 1985) revealed findings very similar to those noted above in the study of children with depression and dysthymia. Specifically, of 35 subjects with a primary diagnosis of attention deficit disorder hyperactivity in this sample, 13 also had an Axis II diagnosis of a learning disability, and 92% were eligible for special education services. Fewer than a third of the remaining 22 ADHD subjects were found eligible.

Undoubtedly, when depression, attention deficit disorder or another problem occurs concurrently with a learning disability, the need for increased special education support comes to the fore. It should be noted that the same phenomenon occurred in a sample of 67 children with a primary diagnosis of conduct disorder when their secondary diagnoses included ADHD or depression and a learning disability (Forness, Kavale, & Lopez, 1993). As mentioned, it is not uncommon for ADHD and depression to overlap conduct disorder (Bird et al., 1993; Newcomer, Barenbaum, & Pearson, 1995).

Learning disabilities subtypes

Explorations of subtypes of children with learning disabilities may help clarify the nature of the relationship between learning disabilities and psychiatric diagnoses (Biederman et al., 1991). Indeed, a great deal of effort in the learning disabilities field has focused on developing more understandable or manageable types of disability based on different patterns of cognitive or psychologic dysfunction (Forness, 1990).

The goal of subtyping research is to divide heterogeneous samples of youngsters with learning disabilities into homogeneous groups based on patterns of performance across a variety of tests or other measurements thought to be critical to the development of learning disabilities. The numbers of subtypes found across various studies have ranged from 2 to 7, with anywhere from 1 to 32 different psychological or neurological measures being used to determine subtype patterns (Kavale & Forness, 1987).

Although a detailed review of learning disabilities subtypes is beyond the scope of this article, Table 3 depicts “consensus” subtypes arrived at by researchers in this area. This table is a brief summary of the review of the literature conducted by Weller and Strawser (1987) on social adaptation of children in different learning disabilities subtypes. The first column presents the five consensus subtypes that have been found. The second column depicts the cognitive deficits or processing patterns associated with each subtype pattern and, just below it, the social problems typically encountered by youngsters in that subtype as found in the studies reviewed. The third column gives the approximate percentages of the typical LD sample accounted for by the particular subtype.

Research on learning disability subtypes suggests that some types of children and adolescents with learning disabilities may be at risk for particular emotional or behavioral disorders (Forness, 1990). Indeed, Weller and Strawser asserted that the five subtypes are clearly identifiable by their differences in adaptive behavior and ability to cope with the environment.

Specifically, these authors provide a comprehensive review of the subtypes and the related adaptive capabilities related to coping mechanisms, adaptive language skills, compensatory behaviors, and behaviors that impact transition from school to community and employment. For instance, individuals in the nonlearning disabled subtype tend to be socially well adjusted and to cope adequately with their environment, whereas individuals in the verbal or nonverbal organization disorder subtypes have impaired adaptive capabilities. More specifically, individuals in the verbal organization disorder subtype tend to act out their wishes and frustrations by visual-spatial motor-based behaviors (e.g., hitting and punching) rather than communicating their wishes and frustrations by talking. Children with nonverbal organization disorders, on the other hand, tend to misperceive, or even withdraw from, social situations.

The study of the adaptive behavior of subtypes of individuals als with learning disabilities has allowed for a clearer understanding and appreciation of individual strengths and limitations in terms of social competence. However, it is possible that more specific research is needed in this area beyond the general notion of social competence. Such research might also focus on developmental psychopathology with reference to specific psychiatric disorders that undergird social skills deficits. Although no research has yet pursued this hypothesis, it seems possible that children with learning disabilities in subtype 2 would qualify for a diagnosis of ADHD, in subtype 3 for a diagnosis of conduct disorder, and in subtype 4 for a diagnosis of depression or dysthymia.

Conclusion

More investigation into the hypothesis that social skills deficits are due to the comorbidity of learning disabilities with specific psychiatric disorders would be informative since there seems to be considerable evidence of emotional or behavioral difficulties in the population of children and adolescents with learning disabilities. As noted, comorbidity of learning disabilities within samples of individuals with disorders such as ADHD and depressive or dysthymic disorder may range as high as 25% (American Psychiatric Association, 1994). This could well mean that differences in social skills ratings between LD and non-LD samples found in previous studies are largely due to extreme scores within LD samples of children with these psychiatric disorders. In addition to comorbidity prevalence rates, the maladaptive social skills patterns of children with specific subtypes of learning disabilities appear to mimic the symptom patterns of children with ADHD and depression or dysthymia, thus providing additional support for the hypothesis that social skills deficits may stem from the comorbidity of learning disabilities with other diagnoses.

There is apparently only one study that directly explores this hypothesis to date. Lopez et al. (in press) examined 60 children with LD in the primary grades on a social skills rating scale. Those with both LD and comorbid ADHD or other emotional or behavioral disorders (N = 42) were significantly lower in social skills, classroom social behavior, and academic competence than those children with only LD (N = 18). There were, however, no significant differences in IQ or achievement. The social skills and related ratings of the LD-only group, moreover, were at or above the normal range, thus tending to confirm the comorbidity hypothesis.

What are the educational placement and treatment implications of the psychiatric comorbidity hypothesis? When ADHD, depression or dysthymia, or another psychiatric disorder occurs concurrently with a learning disability, there appears to be a need for increased special education support. As seen in the study of children characterized by a combination of a learning disability or a related behavioral difficulty or depression (Forness, 1988), “trimorbidity,” or the addition of a learning disability, seemed the surest guarantee of such services. It could well be that children ultimately found eligible for SED or LD categories represent this trimorbidity. The presence of children with learning disabilities in SED programs or children with serious emotional disturbance in LD programs needs to be more systematically investigated. Our traditional assumptions of homogeneity in such programs may not lead to effective intervention for children who are comorbid for both psychiatric disorders and learning disabilities.

In turn, the most effective form of treatment merits careful consideration. Treatment of social skills deficits in children or adolescents with learning disabilities has focused primarily on educational interventions, that is, direct instruction, instead of therapeutic interventions such as psychotherapy (Nelson, 1988). If ADHD and depression account for significant numbers of social skills difficulties in the LD population, the treatment is apt to be much more complex than social skills training. For instance, when a child with learning disabilities reports symptoms typical of those seen in the subtyping research for adaptive skills deficits, ADHD or depression should be assessed in the diagnostic process. Likewise, when interpreting test results and making recommendations, professionals should be cognizant of the possibility that the child may have ADHD or depression. Thus, children or adolescents with learning disabilities whose difficulties in social or behavioral adjustment may well be due to comorbidity with ADHD or depression could benefit from therapeutic, psychological, or even psychopharmacologic treatment (Forness & Kavale, 1991). Psychopharmacologic treatment may in turn produce very different effects on learning as opposed to behavior, and this may be complicated by the presence of several disorders (Forness, Swanson, Cantwell, Guthrie, & Sena, 1992).

Explorations of subtypes of children with learning disabilities and the resultant determination of different patterns of cognitive or psychologic dysfunction may help reduce children’s difficulties to more understandable and manageable types of problems (Forness, 1990). It is unfortunate that previous studies in learning disabilities have largely ignored the potential for comorbidity between learning disabilities and specific psychiatric disorders. Likewise, a variety of medical diagnoses such as prenatal substance abuse, fetal alcohol effects, and fragile X syndrome may potentially have associated diagnoses in both behavioral disorders and learning disabilities (Forness & Kavale, 1994). The need for collaborative efforts between professionals in mental health and learning disabilities may be the most important implications of a psychiatric comorbidity hypothesis.

About the authors:

Stephanie K. San Miguel, Ph.D. is Resident in Psychology, Senior Staff Counselor, Counseling Center, University of Virginia.

Steven R. Forness, Ed.D., is Professor of Psychiatry, University of California., Los Angeles.

Kenneth A. Kavale, Ph.D., is Professor of Special Education, University of Iowa.