This article provides an overview of the challenges faced by and the abilities of adolescents with various disabilities. As clinicians, we must be capable of assessing these characteristics. To begin with, the most compelling conceptual distinction is the difference between physical disability and cognitive disability. In our culture, we rely on verbal expression for communication. When the speed, clarity, or form of verbal communication, or all three, is impaired, society is prone to label an individual as mentally impaired. However, the problem may be motor rather than cognitive. It thus behooves clinicians to evaluate the separate contributions from different organ systems to overall disablement.
TERMS AND DEFINITIONS
Developmental disability is a descriptive term that encompasses several types of disorders. This can occur at any time during the full course of development, from fetal life through adolescence. Throughout childhood, we monitor development in motor, sensory, cognitive, and social functioning. Uneven progress in any one of these domains may result in handicapped function that ranges from barely perceptible to major disability.
Some of the terms used in this article may be defined differently in other contexts. Therefore, definitions that are applicable are reviewed here.
Mental retardation refers to substantial limitations in current functioning. It is characterized by significantly subaverage intellectual functioning, existing concurrently with related limitations in two or more adaptive skill areas (communication, self-care, home living, social skills, community use, self-direction, health and safety, functional academics, leisure, and work), and manifests before 18 years of age.1
Learning disability refers to difficulty in acquiring skills or attaining levels of performance characteristic of non-impaired peers. In most social contexts, a learning disability will result in a social handicap.2 Learning differently is a more recently coined term to de-emphasize the difficulty an individual is experiencing and to minimize the labeling of that difficulty.3 Uneven performance in intellectual domains is characteristic.
Challenging behavior refers to culturally abnormal behavior(s) of such intensity, frequency, or duration that the physical safety of the individual or others is likely to be placed in serious jeopardy, or behavior that is likely to seriously limit the use of ordinary community facilities or result in the individual's being denied access to them.2
Cerebral palsy refers to congenital bilateral, symmetrical atrophy of the nerve cells and gliosis, primarily of the pyramidal tract, resulting in weakness and spasticity, involuntary movements, and ataxia.4 The disorder is thus primarily motor, and cognitive deficits may or may not accompany it.
Mental illness refers to a clinically significant behavioral or psychological syndrome or pattern, associated with distress or disability or a significantly increased risk of death, pain, disability, or loss of freedom. This syndrome or pattern must not be merely an expected and culturally sanctioned response to a particular event; it is considered a manifestation of a behavioral, psychological, or biological dysfunction in the individual.5
Developmental disability refers to disablement of developmental onset that may include mental retardation and difficulty in adaptive function that significantly interferes with an individual's functional independence.
THE CONTEXT OF DEVELOPMENT AND HOW IT RELATES TO STRENGTHS AND WEAKNESSES OF THOSE WITH DEVELOPMENTAL DISABILITIES
The development of an integrated nervous system is molded by practice and use. A ready example is that of amblyopia producing strabismus through lack of use of the weakened visual sensor. A different example is that of an individual with special talents, such as a sport, becoming adept in one physical area but having difficulty in other areas of expression, such as drawing or reading. A frequent occurrence in individuals with developmental disabilities is that there are discrepancies among different domains of function. These inequities cause the individuals' responses to their experiences to be unique, whether developmental disability is present or not. It frequently seems that the disparities are highlighted in individuals with developmental disabilities.
Medical teaching has implied that neurologic disorders resulting in mental retardation are static lesions that would not be expected to worsen during a lifetime. More recent understanding of the development and function of the nervous system does not support such an opinion. Virtually no brain is static in its development or function. However, there is increasing awareness that the capacities and limitations of individual brains vary enormously. These differences are seen in the relative capacity for function (abilities to perform) across differing tasks or conditions. It should come as no surprise, in the 21st century, that each individual with a developmental disability will have unique abilities and strengths, many of which could be overlooked if one were not looking for them.
The underlying etiology for any individual's mental retardation will have an effect on the nervous system's capabilities and capacities for growth. Development will be influenced by environmental Stressors and repeated experiences.6 This variation in developed capacity is observed commonly in the length of time it may take an individual with mental retardation to learn activities or habits: for some it takes a long time and for others it can be quick.
Neuroscientists hypothesize that the loss of brain cells decreases the mental efficiency and flexibility of achieving a solution to a problem. Empirical evidence for this response is the tendency for one habitual behavior to reflect increased arousal, whether from fear, excitement, pain, or confusion.
THE COEXISTENCE OF DEVELOPMENTAL DISABILITIES AND MENTAL ILLNESSES
The possibility of having mental illness(es) or disorders in addition to mental retardation has been discussed widely, often from strongly held opinion rather than clinical observation.7 Mental retardation is not a psychiatric illness in its own right. An individual with mental retardation can usually be expected to behave rationally at his or her operational level.8 Emotional stability and maturity are learned experiences for all individuals, but may develop at different rates. Perceptual and emotional difficulties that are not flexibly handled can become permanent deficits in an individual's ability to function. This can happen when pathological processes in the brain are establishing themselves. Symptoms may wax and wane, but psychiatric function becomes impaired. This is a relative definition for development of a psychiatric disorder. In contrast, an adjustment disorder is shorter lived and often of less severe pathology.5 The ". . . available studies agree on two essential points: that mental retardation is a risk factor for developing a mental disorder and that all categories of 'usual' mental disorders are seen in this population."9
Certain etiopathologies of mental retardation are associated with known psychiatric illnesses. For example, Prader-Willi syndrome is associated with bipolar mood (manic-depressive) disorder. The cumulative interaction of epilepsy and mental retardation increases the risk of recurrent major depression or psychosis. Additionally, having mental retardation of any cause alters the individual's response to common psychiatric illnesses.
Anxiety disorders and sleep disorders are two of the most common problems in the general population.5 Having anxiety to alert oneself to potential or real danger, to increase the intensity of effort and concentration, is a useful characteristic in normal humans. Too much anxiety is paralyzing. The need to modulate overwhelming anxiety is even greater, in general, for individuals with mental retardation than for the normal population. Life events may also lead to greater anxiety. The reported prevalence of a past experience of physical abuse, sexual abuse, or both is threefold greater for individuals with mental retardation than for individuals with a personality disorder.10 Finally, sensitivity to sensory information may be heightened for individuals who are not verbal. This raises the level of discomfort, especially when the situation does not make sense.
The severity of mental retardation does not influence the prevalence of psychiatric illness in a reliable way. A greater incidence of psychiatric disorders is described for individuals with IQs between 45 and 70, and a greater incidence of neurologic disorders is described for those with IQs of less than 45. In part, these differences are due to an increase in the rate of seizure disorders and a decrease in verbal communication abilities for individuals with IQs of less than 45 (as a group).
Many individuals with severe mental retardation engage in self-injurious behavior. The etiologies for hurting oneself vary, from responding to focal pain to becoming overstimulated. Morgan and Mackay11 studied the frequency and types of self-injurious behavior among more than 500 individuals with mental retardation. The likelihood of self-injurious behavior was increased with increased severity of learning disability. Striking the head or the face was the most frequent injury; more than 20% had a high risk of serious injury and permanent damage. When patients are distracted or prevented from engaging in one behavior, they will tend to find another variation. This provides another example of the persistent adaptation of the nervous system.
ENVIRONMENTAL EFFECTS ON THE INDIVIDUAL WITH MENTAL RETARDATION
The unique biological properties of man, as of all creatures, provide both abilities and limitations . . . about people who have difficulty in coping with some life-adjustive tasks because of impaired general intelligence. The extent of their coping or adaptive difficulty is primarily related to the degree of intellectual impairment, though it is also much affected by both society's general attitude toward persons with limited intelligence and the services provided them.12
Disordered development of the nervous system) causes changes in the response patterns of the neuronal substrate to sensory stimulation, including medications. There are alterations in threshold (raised and lowered), amplification of incoming stimuli, ability to modulate responses (output), and sensitivity to side effects (especially for drugs). Medical and metabolic illness or perturbations seem to more readily cause a disturbance of the associative pathway function, even to the point of encephalopathy.
Supports for psychiatric problems, physical problems, chronic medical conditions, and temperament are usually integrated through multidisciplinary teams. The pediatrician is an integral part of the team, regardless of whether he or she attends the meetings in person. Disruption in schedule, method of interaction, noise, ambient activities, or specifically directed activities may induce new or severe behavioral problems. At times, it may be appropriate to invite the entire team, or representatives of the team, to attend medical appointments. At other times, it will be imperative to establish some individual time with the patient and set up some safe and individualized boundaries. Changes in behavior must be carefully analyzed for the possibility of an incipient medical infection or metabolic disorder as their cause. Pain and gastrointestinal complaints are the most frequent causes of disturbed behavior in all individuals, including those with mental retardation.
Behavioral manifestations of distress in the individual with mental retardation, head injury, or both cannot be assumed to reflect neurotransmitter disruptions that have been ascribed to similar symptom constellations in the "normal" population. Each therapeutic intervention must be tried systematically to assess its effect on the overall functioning of the individual. This is true for behavioral and sensory therapies and pharmacologie therapies. Syndromes such as psychiatric illnesses and the epilepsies must be carefully evaluated for each individual. For individuals with neurologic and psychiatric problems, the primary care physician is indispensable for maintaining safety and minimizing drug-drug interactions.
UNIQUE AND IDIOSYNCRATIC RESPONSES TO DRUGS
A known chemical compound will have different effects on the brains of individuals with no pathology compared with those with pathology, and the differences between the pathological processes (whether we know what they are or are not) will cause differences in the therapeutic response to the same compound. The segregation of mental retardation into four categories by IQ cluster has not assisted in predicting the response to psychopharmacologic agents. There are no data that can help anticipate how an individual with mild mental retardation will respond to an antidepressant, or whether an individual with profound mental retardation will require either half or twice the usual dosage. Neither are there data that antipsychotics will have greater or lesser efficacy in one category depending on the severity of mental retardation. It is known that the more neurologic and psychiatric illness the individual has, the more likely it is that he or she will have untoward side effects from medications. This does not predict that there will be unwanted side effects, just that they are more likely.
Pharmacologic treatments may need to be adjusted when offering supportive medications. Many medications affecting behavior (eg, anticonvulsants or antidepressants) are competitively metabolized by the liver, altering baseline levels of other medications. General principles of prescribing include using small dosages, starting at a low dosage, increasing the dosage slowly, and looking for unexpected changes in behavior. Specific treatments received from a number of specialists (eg, gastroenterologists, neurologists, psychiatrists, and endocrinologists) need to be compared with each other and potential positive and negative interactions among therapies and medications need to be scrutinized.
THE MAINSTREAMlNG OF CHILDREN WITH DEVELOPMENTAL DISADILITIES
There is increasing emphasis placed on the value of including children with developmental disabilities within "mainstream" classrooms. A recent study in California high schools supports the benefit to students with and without disabilities.13 In this study, students without identified disabilities reported increased awareness of human rights and tolerance for others, new learning opportunities, and awareness of their own and adult attitudes that were inconsistent.
It is helpful when disability-related behaviors can be separated from other behaviors. One example was that of a student, identified with disabilities, who lit a small piece of paper on fire in chemistry class. Other students who had done the same thing were sent out of the class, thereby failing the laboratory. This student did not receive the same consequence. It was the opinion of the other students that his behavior was not related to his disability. The value of true inclusion is learning from social interactions, experiencing natural consequences of actions within a meaningful context. Well-intentioned sheltering does not protect the student with disabilities, the other students, or the school system as a whole. Realistic expectations and supports permit the adolescent to discover how to grow into an appropriate adult role. Questions about school experiences and data about his or her behavior in school are essential to evaluating the continuing growth of the adolescent patient.
Clinicians must have an accurate understanding of the individual preferences and identities of their patients with developmental disabilities. Issues of puberty, sexual functioning, and sexual orientation and their interaction with medical conditions, medications, and intense support from and dependence on other individuals need to be integrated. For example, for an adolescent to experience more appropriate peer relationships, it is important that he or she decrease self-stimulating behavior in public settings. It is also a safety concern that sexual predators not have access to an individual who is vulnerable.
Parents and teachers often inaccurately minimize the sexual interests of an individual with a developmental disability. Such an individual may have an increased sexual drive, or sexual behavior may be a method to express his or her individuality in ways that get other people to pay attention. An important consideration is that the physical maturity of the individual is not slowed or altered, even when there is slowed cognitive development. Sexual experiences should be encouraged within the framework of the individual's values and those of his or her family. Health concerns should be clearly stated, and the means to protect the individual from sexually transmitted diseases should be ensured. The topic of sexuality can be included most easily and directly within the context of general health care.
One limitation in allopathic medical practice is the tendency to present disease as an aberration from the normal state of human experience. We are taught to seek cures to diseases. The medical curriculum teaches, with increasing emphasis, observing individuals during the lifespan and awareness of the aging process. However, the practical application and delivery of services remains focused on acute, intermittent delivery of care. Chronic illnesses, as a rule, are not served well by this model. Effective strategies for prevention are not assisted by this model. The recognition of mental retardation as a chronic condition is important in communicating within the medical community. It is critical for increasing the awareness and realization that developmental disorders of the brain will be dynamic during the lifespan.
Adolescents with developmental disorders must adjust to this time of change like everyone else. As they do this, each will bring unique characteristics and represent unique challenges to his or her parents and pediatrician. Understanding the strengths and weaknesses of each individual and how he or she reacts to the environment will help the pediatrician understand these adolescents and their families.
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