14.5 SUMMING UP

Intellectual Disability (Intellectual Developmental Disorder)

• The diagnosis of intellectual disability typically involves both cognitive deficits that are significantly below normal and impaired daily functioning in conceptual, social, and/or practical areas. Some people with intellectual disability—particularly at the severe or profound level—may have difficulty communicating verbally.
• Neurological factors are the primary direct cause of most cases of intellectual disability—usually a genetic abnormality or prenatal exposure to a teratogen, which in turn alters brain structure and function.
• Many types of intellectual disability can be prevented, such as those related to PKU and lead poisoning.
• Interventions are designed to improve the person’s functioning by increasing his or her communication and daily living skills.
• Legally, children with an intellectual disability are entitled to special education and related services, tailored to their individual needs.

Autism Spectrum Disorder

• Autism spectrum disorder (ASD) involves two types of problems: (1) significant deficits in communication and social interaction skills and (2) stereotyped behaviors or narrow interests.
• Many people with ASD also have comorbid intellectual disability when tested with conventional intelligence tests; on tests that do not rely on verbal abilities, people with ASD tend to score in the average range or higher.
• Neurological factors that underlie ASD include abnormal connections and communication among different brain areas.
• Psychological symptoms of ASD include deficits in shifting attention, in mental flexibility, and an impaired theory of mind.
• Social symptoms of ASD include problems in recognizing emotion in the voices and faces of others and in understanding the give and take of social communication.
• Treatment for ASD that targets psychological factors includes applied behavior analysis to modify maladaptive behaviors. Treatments that target psychological and social factors focus on teaching the person to recognize conventional social cues, to read the emotional expressions of others, and to communicate, as well as how to initiate and respond in social situations.

Specific Learning Disorder: Problems with the Three Rs

• Specific learning disorder is characterized by well-below-average skills in reading, writing, or math, based on the expected level of performance for the person’s age, general intelligence, cultural group, gender, and education level. DSM-5 includes three types of learning disorders related to: reading (dyslexia), written expression, and mathematics (dyscalculia).
• Dyslexia appears to result from disruptions in brain systems that process language and that process visual stimuli. Treatment for dyslexia may involve various cognitive techniques to compensate for reading difficulties.

Disorders of Disruptive Behavior and Attention

• Conduct disorder is characterized by a violation of the basic rights of others or of societal norms that are appropriate to the person’s age. Conduct disorder involves four types of behavior: aggression to people and animals, destruction of property, deceitfulness or theft, and serious violation of rules. The disorder may begin in childhood or adolescence. Conduct disorder is commonly comorbid with attention-deficit/hyperactivity disorder.
• Childhood-onset conduct disorder with callous and unemotional traits has the highest heritability among the various types of conduct disorder; this variant is also associated with more severe symptoms.
• Oppositional defiant disorder is characterized by angry or irritable mood, defiance or argumentative behavior, or vindictiveness. The behaviors are usually not violent, nor do they cause severe harm, and they often occur only in certain contexts.
• Attention-deficit/hyperactivity disorder (ADHD) is characterized by inattention, hyperactivity, and/or impulsivity.
• Oppositional defiant disorder, conduct disorder, and ADHD are highly comorbid, making it difficult to sort out factors that contribute uniquely to one of the disorders.
• Neurological factors that contribute to ADHD include frontal lobe problems and genes. Too little dopamine and imbalances in other transmitters also play a role.
• Psychological factors associated with ADHD include low self-esteem and difficulty recognizing facial expressions of anger and sadness.
• Social factors that contribute to ADHD include parents’ not giving children enough credit for their positive behaviors.
• Treatment targeting neurological factors in ADHD involves medication—typically methylphenidate or atomoxetine. Treatments targeting psychological factors include behavioral methods to increase a person’s ability to tolerate frustration and to delay reward, and cognitive methods to enhance social problem-solving ability. Treatments that target social factors include group therapy and comprehensive treatments such as contingency management, parent management training, and multisystemic therapy.