this enables a diagnosis to avoid the pitfall of the flynn effect, which is a consequence of changes in population iq test performance changing iq test norms over time. distinction from other disabilities clinically, intellectual disability is a subtype of cognitive deficit or disabilities affecting intellectual abilities, which is a broader concept and includes intellectual deficits that are too mild to properly qualify as intellectual disability, or too specific (as in specific learning disability), or acquired later in life through acquired brain injuries or neurodegenerative diseases like dementia. cognitive deficits may appear at any age. developmental disability is any disability that is due to problems with growth and development. this term encompasses many congenital medical conditions that have no mental or intellectual components, although it, too, is sometimes used as a euphemism for intellectual disability. limitations in more than one area adaptive behavior, or adaptive functioning, refers to the skills needed to live independently (or at the minimally acceptable level for age). to assess adaptive behavior, professionals compare the functional abilities of a child to those of other children of similar age. to measure adaptive behavior, professionals use structured interviews, with which they systematically elicit information about persons' functioning in the community from people who know them well. there are many adaptive behavior scales, and accurate assessment of the quality of someone's adaptive behavior requires clinical judgment as well. certain skills are important to adaptive behavior, such as: daily living skills, such as getting dressed, using the bathroom, and feeding oneself communication skills, such as understanding what is said and being able to answer social skills with peers, family members, spouses, adults, and others other specific skills can be critical to an individual's inclusion in the community and to develop appropriate social behaviors, as for example being aware of the different social expectations linked to the principal lifespan stages (i.e., childhood, adulthood, old age). the results of a swiss study suggest that the performance of adults with id in recognizing different lifespan stages is related to specific cognitive abilities and to the type of material used to test this performance. management by most definitions, intellectual disability is more accurately considered a disability rather than a disease. intellectual disability can be distinguished in many ways from mental illness, such as schizophrenia or depression. currently, there is no "cure" for an established disability, though with appropriate support and teaching, most individuals can learn to do many things. causes, such as congenital hypothyroidism, if detected early may be treated to prevent the development of an intellectual disability. there are thousands of agencies around the world that provide assistance for people with developmental disabilities. they include state-run, for-profit, and non-profit, privately run agencies. within one agency there could be departments that include fully staffed residential homes, day rehabilitation programs that approximate schools, workshops wherein people with disabilities can obtain jobs, programs that assist people with developmental disabilities in obtaining jobs in the community, programs that provide support for people with developmental disabilities who have their own apartments, programs that assist them with raising their children, and many more. there are also many agencies and programs for parents of children with developmental disabilities. beyond that, there are specific programs that people with developmental disabilities can take part in wherein they learn basic life skills. these "goals" may take a much longer amount of time for them to accomplish, but the ultimate goal is independence. this may be anything from independence in tooth brushing to an independent residence. people with developmental disabilities learn throughout their lives and can obtain many new skills even late in life with the help of their families, caregivers, clinicians and the people who coordinate the efforts of all of these people. there are four broad areas of intervention that allow for active participation from caregivers, community members, clinicians, and of course, the individual(s) with an intellectual disability. these include psychosocial treatments, behavioral treatments, cognitive-behavioral treatments, and family-oriented strategies. psychosocial treatments are intended primarily for children before and during the preschool years as this is the optimum time for intervention. this early intervention should include encouragement of exploration, mentoring in basic skills, celebration of developmental advances, guided rehearsal and extension of newly acquired skills, protection from harmful displays of disapproval, teasing, or punishment, and exposure to a rich and responsive language environment. a great example of a successful intervention is the carolina abecedarian project that was conducted with over 100 children from low socioeconomic status families beginning in infancy through pre-school years. results indicated that by age 2, the children provided the intervention had higher test scores than control group children, and they remained approximately 5 points higher 10 years after the end of the program. by young adulthood, children from the intervention group had better educational attainment, employment opportunities, and fewer behavioral problems than their control-group counterparts. core components of behavioral treatments include language and social skills acquisition. typically, one-to-one training is offered in which a therapist uses a shaping procedure in combination with positive reinforcements to help the child pronounce syllables until words are completed. sometimes involving pictures and visual aids, therapists aim at improving speech capacity so that short sentences about important daily tasks (e.g. bathroom use, eating, etc.) can be effectively communicated by the child. in a similar fashion, older children benefit from this type of training as they learn to sharpen their social skills such as sharing, taking turns, following instruction, and smiling. at the same time, a movement known as social inclusion attempts to increase valuable interactions between children with an intellectual disability and their non-disabled peers. cognitive-behavioral treatments, a combination of the previous two treatment types, involves a strategical-metastrategical learning technique that teaches children math, language, and other basic skills pertaining to memory and learning. the first goal of the training is to teach the child to be a strategical thinker through making cognitive connections and plans. then, the therapist teaches the child to be metastrategical by teaching them to discriminate among different tasks and determine which plan or strategy suits each task. finally, family-oriented strategies delve into empowering the family with the skill set they need to support and encourage their child or children with an intellectual disability. in general, this includes teaching assertiveness skills or behavior management techniques as well as how to ask for help from neighbors, extended family, or day-care staff. as the child ages, parents are then taught how to approach topics such as housing/residential care, employment, and relationships. the ultimate goal for every intervention or technique is to give the child autonomy and a sense of independence using the acquired skills they have. in a 2019 cochrane review on beginning reading interventions for children and adolescents with intellectual disability, small to moderate improvements in phonological awareness, word reading, decoding, expressive and receptive language skills, and reading fluency were noted when these elements were part of the teaching intervention. although there is no specific medication for intellectual disability, many people with developmental disabilities have further medical complications and may be prescribed several medications. for example, autistic children with developmental delay may be prescribed antipsychotics or mood stabilizers to help with their behavior. use of psychotropic medications such as benzodiazepines in people with intellectual disability requires monitoring and vigilance as side effects occur commonly and are often misdiagnosed as behavioral and psychiatric problems. epidemiology intellectual disability affects about 2–3% of the general population. 75–90% of the affected people have mild intellectual disability. non-syndromic or idiopathic id accounts for 30–50% of cases. about a quarter of cases are caused by a genetic disorder. cases of unknown cause affect about 95 million people as of 2013. it is more common in males and in low to middle income countries. history intellectual disability has been documented under a variety of names throughout history. throughout much of human history, society was unkind to those with any type of disability, and people with intellectual disability were commonly viewed as burdens on their families. greek and roman philosophers, who valued reasoning abilities, disparaged people with intellectual disability as barely human. the oldest physiological view of intellectual disability is in the writings of hippocrates in the late fifth century bce, who believed that it was caused by an imbalance in the four humors in the brain. in ancient rome people with intellectual disabilities had limited rights and were generally looked down upon. they were considered property and could be kept slaves by their father. these people could also not marry, hold office, or raise children. many of them were killed early in the childhood, and then dumped into the tiber in order to avoid them burdening society. however, they were exempt from their crimes under roman law, and they were also used to perform menial labor. caliph al-walid (r. 705–715) built one of the first care homes for individuals with intellectual disabilities and built the first hospital which accommodated intellectually disabled individuals as part of its services. in addition, al-walid assigned each intellectually disabled individual a caregiver. until the enlightenment in europe, care and asylum was provided by families and the church (in monasteries and other religious communities), focusing on the provision of basic physical needs such as food, shelter, and clothing. negative stereotypes were prominent in social attitudes of the time. in the 13th century, england declared people with intellectual disabilities to be incapable of making decisions or managing their affairs. guardianships were created to take over their financial affairs. in the 17th century, thomas willis provided the first description of intellectual disability as a disease. he believed that it was caused by structural problems in the brain. according to willis, the anatomical problems could be either an inborn condition or acquired later in life. in the 18th and 19th centuries, housing and care moved away from families and towards an asylum model. people were placed by, or removed from, their families (usually in infancy) and housed in large professional institutions, many of which were self-sufficient through the labor of the residents. some of these institutions provided a very basic level of education (such as differentiation between colors and basic word recognition and numeracy), but most continued to focus solely on the provision of basic needs of food, clothing, and shelter. conditions in such institutions varied widely, but the support provided was generally non-individualized, with aberrant behavior and low levels of economic productivity regarded as a burden to society. individuals of higher wealth were often able to afford higher degrees of care such as home care or private asylums. heavy tranquilization and assembly-line methods of support were the norm, and the medical model of disability prevailed. services were provided based on the relative ease to the provider, not based on the needs of the individual. a survey taken in 1891 in cape town, south africa shows the distribution between different facilities. out of 2046 persons surveyed, 1,281 were in private dwellings, 120 in jails, and 645 in asylums, with men representing nearly two-thirds of the number surveyed. in situations of scarcity of accommodation, preference was given to white men and black men (whose insanity threatened white society by disrupting employment relations and the taboo sexual contact with white women). in the late 19th century, in response to charles darwin's on the origin of species, francis galton proposed selective breeding of humans to reduce intellectual disability. early in the 20th century, the eugenics movement became popular throughout the world. this led to forced sterilization and prohibition of marriage in most of the developed world and was later used by adolf hitler as a rationale for the mass murder of people with intellectual disability during the holocaust. eugenics was later abandoned as an violation of human rights, and the practice of forced sterilization and prohibition from marriage was discontinued by most of the developed world by the mid-20th century. in 1905, alfred binet produced the first standardized test for measuring intelligence in children. although ancient roman law had declared people with intellectual disability to be incapable of the deliberate intent to harm that was necessary for a person to commit a crime, during the 1920s, western society believed they were morally degenerate. ignoring the prevailing attitude, civitans adopted service to people with developmental disabilities as a major organizational emphasis in 1952. their earliest efforts included workshops for