According to the dsm-5, an individual with an iq below 70 would be given a diagnosis of:

Prognosis

In children with severe ID, the prognosis is often evident by early childhood. Mild ID might not always be a lifelong disorder. Children might meet criteria for GDD at an early age, but later the disability can evolve into a more specific developmental disorder [communication disorder, autism, specific learning disability, or borderline normal intelligence]. Others with a diagnosis of mild ID during their school years may develop sufficient adaptive behavior skills that they no longer fit the diagnosis as adolescents or young adults, or the effects of maturation and plasticity may result in children moving from one diagnostic category to another [from moderate to mild ID]. Conversely, some children who have a diagnosis of a specific learning disability or communication disorder might not maintain their rate of cognitive growth and may fall into the range of ID over time.

The apparent higher prevalence of ID in low- and middle-income countries is of concern given the limitations in available resources.Community-based rehabilitation [CBR] is an effort promoted by WHO over the past 4 decades as a means of making use of existing community resources for persons with disabilities in low-income countries with the goal of increasing inclusion and participation within the community. CBR is now being implemented in >90 countries, although the efficacy of such programs has not been established.

The long-term outcome of persons with ID depends on the underlying cause, degree of cognitive and adaptive deficits, presence of associated medical and developmental impairments, capabilities of the families, and school and community supports, services, and training provided to the child and family [Table 53.7]. As adults, many persons with mild ID are capable of gaining economic and social independence with functional literacy, but they may need periodic supervision [especially when under social or economic stress]. Most live successfully in the community, either independently or in supervised settings.

For persons with moderate ID, the goals of education are to enhance adaptive abilities and “survival” academic and vocational skills so they are better able to live and function in the adult world [Table 53.7]. The concept of supported employment has been very beneficial to these individuals; the person is trained by a coach to do a specific job in the setting where the person is to work, bypassing the need for a “sheltered workshop” experience and resulting in successful work adaptation in the community. These persons generally live at home or in a supervised setting in the community.

As adults, people with severe to profound ID usually require extensive to pervasive supports [Table 53.7]. These individuals may have associated impairments, such as cerebral palsy, behavioral disorders, epilepsy, or sensory impairments, that further limit their adaptive functioning. They can perform simple tasks in supervised settings. Most people with this level of ID can live in the community with appropriate supports.

Abstract

Borderline intellectual functioning [BIF], that is to say, tested IQ levels in the range of 70–84/85, is prevalent, affecting about 12%–14% of the population depending on the exact level for “diagnostic” cutoff. In the current Diagnostic and Statistical Manual of Mental Disorders, BIF does not have a separate diagnostic category but can be categorized with a V-code. Children and adolescents with BIF usually struggle both as regards school performance and in respect of social functioning. BIF is common in attention deficit hyperactivity disorder, but sometimes attention problems in schoolchildren with BIF may be a consequence of nonadapted academic demands. Autism and BIF may also coexist, and there are many cases of so-called high-functioning autism who are high functioning only in the sense that they do not meet criteria for intellectual disability, but function in the area of BIF. Currently, too little attention is given to the negative effects of BIF on child development and adaptation. Learning, academic, and behavioral problems and grade retention may be markers of BIF. Our diagnostic and classification manuals need to have specific categories that clarify the problems that BIF entails so that affected individuals can avail themselves of better educational support and understanding.

Clinical Features

ID, also known as intellectual developmental disorder, requires limitations in both intellectual ability and deficits in adaptive skills, as expressed in conceptual, social, and practical adaptive skills, relative to the child’s age, experience, and environment. Specifically, the diagnosis requires that the following criteria are met: [1] Deficits in intellectual functioning [i.e., reasoning, abstract thinking, learning, both experiential and academic] that must be confirmed through both clinical evaluation and individualized, standardized IQ testing; [2] limitations in adaptive functioning that result in failure in meeting developmentaland social standards for personal independence and social responsibility; and [3] onset of intellectual and adaptive deficits occurs during the developmental period. Moreover, the level and severity of ID [mild, moderate, severe, and profound] is defined on the basis of adaptive skills rather than the IQ score. The definition links the severity of ID to the degree of community support required to achieve optimal independence [Katz and Lazcano-Ponce, 2008]. Mild ID indicates the need for intermittent support; moderate ID for limited support; severe ID for extensive support; and profound ID for pervasive support. Although both intellectual and adaptive functioning are pertinent in defining ID, impairment of adaptive function is more likely to be the presenting feature than low IQ; however, it is expected that there is an association between intellectual functioning and adaptive skills.

The termglobal developmental delay [GDD] is used to describe children under the age of 5 years with significant delays in developmental milestones in several areas of functioning [APA, 2013b]. GDD can be diagnosed using a standardized test, which shows performance at least 2 SD below the mean in at least two developmental domains: motor, speech and language, cognition, personal-social, and/or adaptive [daily living]. The diagnosis of ID is not used for children under 5 years old since IQ scores are not reliable until after 5 years and because some children with a GDD diagnosis will not meet criteria for ID as they get older.

The IQ definition of ID uses 100 as the mean and 15 as the SD. An IQ score of 65–75 [≈2 SD below the mean, with a variation of ±5 points] is the demarcation point. Previously, children with an IQ of 55–69 were considered mild ID, those with an IQ of 40–54, as moderate ID; those with an IQ of 25–39, severe ID; and those with an IQ under 25, profound ID.

The prevalence of ID varies due to differences in diagnostic approach, population characteristics, and study design. In the general population, it is considered to be 1% when ID is defined as deficits in both adaptive and intellectual functioning [Harris, 2006; Maulik et al., 2011; Szymanski and King, 1999]. The prevalence of intellectual deficits only [IQ < 75], based on IQ score alone, is 3% [Szymanski and King, 1999]. Mild ID represents the majority [85%], but roughly 0.4% of the general population is severely intellectually disabled. As a rule, those with severe ID are more likely to have a definable biological cause, whereas those with mild ID tend to come from socially disadvantaged backgrounds and often have a family history of borderline intellectual function or mild ID [Kaufman et al., 2010; Stromme and Magnus, 2000]. The prevalence of GDD [in children under 5 years] is estimated at 1%–3% [Shevell et al., 2003]. The ratio of boys to girls with ID, especially mild ID, is 1.4:1. Male excess is present in ASD with ID, syndromic X-linked ID [S-XLID] [associated with a specific phenotype], and nonsyndromic X-linked ID [NS-XLID]. About 15% of males with ID have X-linked intellectual disability [XLID] [Stevenson and Schwartz, 2009]. About 25% of all males with severe ID have XLID, and almost 50% of all cases of mild ID are due to XLID [Partington et al., 2000; Ropers and Hamel, 2005]. The recurrence of ID in families with one previous child with severe ID is reported to be between 3% and 9% [CDC, 2009].

Borderline Intellectual Functioning

Children in the Borderline Intellectual Functioning [BIF] group were included if they had prior FSIQ scores between 71 and 84 on a standardized measure of ability or met DSM-5 criteria for a diagnosis of borderline intellectual functioning. Data for the BIF group are shown in Table 10.4.

On the WISC-V, the borderline group obtained a mean FSIQ of 80.4, which was statistically significantly lower than the matched control group. The pattern of scores on the primary indexes was similar to those observed in the Mild and Moderate ID groups, although with higher means as expected. The highest score was obtained on the PSI, followed by the FRI, with lower scores across the other three domains. The ancillary index scores were similar to the primary index scores with mean scores in the 75–85 range. Unlike the Mild and Moderate ID groups, scores on the AWMI were not lower than scores on the WMI. In general, complementary subtest and index scores were similar to those observed on the primary and ancillary subtest and index scores. In addition, as noted earlier in the chapter and consistent with prior research, variability in group performance across subtests decreased as severity of disability moved from borderline to mild to moderate levels of intellectual functioning. The range of mean scores across subtests for the BIF group was 5.7–10.4, whereas it was 3.2–6.1 for Mild-ID and 2.0–4.6 for Moderate-ID.

Axis II

Axis II contains personality disorders [Table 17-2] and mental retardation [Table 17-3]. Borderline intellectual functioning, although not considered a mental disorder, is also coded on Axis II. As with Axis I, multiple diagnoses should be listed on Axis II if present. If an Axis II diagnosis, rather than one or more co-morbid Axis I disorders, is the primary clinical concern, this may be noted by qualifying it in parentheses as principal diagnosis or reason for visit. Given that additional evaluation time or clinical information may be needed to diagnose Axis II disorders, it may be appropriate to specify no diagnosis or diagnosis deferred. In addition, personality traits that do not meet full criteria for a personality disorder, but are nonetheless maladaptive, may be listed on Axis II without the use of a diagnostic code, as may defensive patterns.4 The DSM-IV-TR provides examples of specific defensive patterns in Appendix B, in the “Glossary of Specific Defense Mechanisms and Coping Styles.” The Defensive Functioning Scale [pp. 807-810]5 is included as a “Proposed Axis for Further Study,” with the suggestion that this hierarchical ranking of defensive styles be placed below Axis V. In practice, inclusion of specific defensive patterns or a defensive level might be more easily incorporated into Axis II.4 Box 17-5 is an example of using Axis II in a way that may enhance clinical communication within a mental health care system.

Introduction

Intellectual disability, formerly called mental retardation [MR] is defined as having an IQ score below 70 whereas an IQ score in the range of 71–84 is termed as “borderline intellectual functioning”. Mental retardation is further subgrouped according to levels of IQ scores: mild MR [IQ: 50–70], moderate MR [IQ: 36–49], severe MR [IQ: 35–20], and profound MR [IQ