Disability fraud is the receipt of payment(s) intended for the disabled from a government agency or private insurance company by one who should not be receiving them, or the receipt of a higher amount than one who is entitled to them should be receiving. There are various acts that may constitute disability fraud. These include feigning a medical problem in order to be declared disabled, exaggeration of an existing medical problem that potentially can but in reality does not render the person disabled, continuing to receive payments after having recovered from a medical problem, or continuing to receive payments while working (usually unreported) above the allowable level for those receiving the payments.

Disability fraud can be harder to detect than other forms of fraud, as the majority of people receiving disability payments (at least 90%) do not use a wheelchair or walker, while at the same time, many people who need wheelchairs would not qualify for disability payments. Since most disabilities are "silent" (meaning that they cannot be seen by others), it is not easy to visually determine if a person receiving disability is not disabled. Such people are often able to perform physical activities, but have some other underlying cause of their disability. It is therefore common for people to believe they must report a neighbor who they see, for example, climbing on the roof while collecting disability payments, but this is not always the case.

Meanwhile, true disability fraud cases exist, for which it is hard to determine the cause as being fraudulent. Often, the perpetrator claims to have a medical condition to be declared disabled. Some medical conditions are truly debilitating and make it impossible or difficult to work if one has them, but are hard to prove against one's own word that one does not have them. These include chronic fatigue syndrome, chronic pain, or various mental disorders. Even if one with one of them is viewed engaging in some other "work-like" activity not for pay, they may have difficulty holding a job.

It is possible that the illegal recipient of the disability payments is not truly disabled, and may have a case of work aversion, which in many countries is not alone considered a valid reason for being declared disabled, or the person may otherwise lack a work ethic. Others who are receiving payments are actually working, but are not reporting their employment and collecting their income in a manner that cannot easily be detected.

Disability fraud can result in denial of future benefits as well as criminal prosecution.

The United States Social Security Administration accepts reports from the public for the following types of fraud:

- Applicants who state they are not married when they are. Those receiving Supplemental Security Income (SSI) can have their benefits reduced by their spouse's income and assets, so some applicants may wish to hide the existence, income, or assets of their spouse.

- Claims of blindness. In particular, the Social Security Administration is concerned about those who declare they are blind and unable to drive, but are later found to be in possession of a driver's license and are observed (legally) operating a motor vehicle.

- Unreported income. Some types of income that often go unreported are from renting out a portion of one's home, or from an insurance policy.

- Employment changes, in a person who was not working at the time they applied for and started to receive benefits, but has since returned to work.

- A person who is living in an institution, such as a long-term care facility or a prison.

- A person who is the legal custodian (representative payee) of a disabled person's money spending it on some expense other than that of the disabled person.

- A person who cashes the checks of a deceased person.

Malingering is the fabricating of symptoms of mental or physical disorders for a variety of reasons such as financial compensation (often tied to fraud); avoiding school, work or military service; obtaining drugs; or as a mitigating factor for sentencing in criminal cases. It is not a medical diagnosis. Malingering is typically conceptualized as being distinct from other forms of excessive illness behaviour such as somatization disorder and factitious disorder, e.g., in DSM-5, although not all mental health professionals agree with this formulation.

Failure to detect actual cases of malingering imposes an economic burden on health care systems; workers compensation programs; and disability programs, e.g., Social Security Disability Insurance (United States) and U.S. Department of Veterans Affairs disability benefits. False attribution of malingering often harms genuine patients or claimants.

A disability pretender is subculture term meaning a person who behaves as if he or she were disabled. It may be classified as a type of factitious disorder or as a medical fetishism.

One theory is that pretenders may be the "missing link" between devotees and wannabes, demonstrating an assumed continuum between those merely attracted to people with disabilities and those who actively wish to become disabled. Many wannabes use pretending as a way to appease the intense emotional pain related to having body integrity identity disorder.

Pretending takes a variety of forms. Some chatroom users on internet sites catering to devotees have complained that chat counterparts they assumed were female were revealed as male devotees. This form of pretending (where a devotee derives pleasure by pretending to be a disabled woman) may indicate a very broad predisposition to pretending among devotees.

Pretending includes dressing and acting in ways typical of disabled people, including making use of aids (Walking sticks, crutches, wheelchairs, mobility scooters, white canes, etc. Pretending may also take the form of a devotee persuading his or her sexual partner to play the role of a disabled person. Pretending may be practiced in private, in intimacy, or in public, and may occupy surprisingly long periods. In the latter case, some pretenders hope that the disability may become permanent, such as through tissue necrosis caused by constricted blood supply.

Cheating at the Paralympic Games has caused scandals that have significantly changed the way in which the International Paralympic Committee (IPC) manages the events.

Testing for performance-enhancing drugs has become increasingly strict and more widespread throughout the Games, with powerlifting seeing the most positive results. Competitors without disabilities have also competed in some Paralympic Games, with the Spanish entry in the intellectually disabled basketball tournament at the 2000 Summer Paralympics being the most controversial.

For much of the second phase of his career, Cyclist Lance Armstrong faced constant allegations of doping. Armstrong consistently denied allegations of doping until a partial confession during a broadcast interview with Oprah Winfrey in January 2013.

The symptoms most commonly feigned include those associated with mild head injury, fibromyalgia, chronic fatigue syndrome, and chronic pain. Generally, malingerers complain of psychological disorders such as anxiety. Malingering may take the form of dishonest complaints of chronic whiplash pain from automobile accidents. The psychological symptoms experienced by survivors of disaster (post-traumatic stress disorder) are also faked by malingerers.

Individuals use a variety of methods to feign symptoms of illness. Some of these include harming oneself, trying to convince medical professionals one has a disease after learning about its details (such as symptoms) in medical textbooks, taking drugs that provoke certain symptoms common in some diseases, performing excess exercise to induce muscle strain or other physical types of ailments, and overdosing on drugs.

A fasting girl was one of a number of young Victorian girls, usually pre-adolescent, who claimed to be able to survive over indefinitely long periods of time without consuming any food or other nourishment. In addition to refusing food, fasting girls claimed to have special religious or magical powers.

The ability to survive without nourishment was attributed to some saints during the Middle Ages, including Catherine of Siena and Lidwina of Schiedam, and regarded as a miracle and a sign of sanctity. Numerous cases of fasting girls were reported in the late 19th century. Believers regarded such cases as miraculous.

In some cases, the fasting girls also exhibited the appearance of stigmata. Doctors, however, such as William A. Hammond ascribed the phenomenon to fraud and hysteria on the part of the girl. Historian Joan Jacobs Brumberg believes the phenomenon to be an early example of anorexia nervosa.

There are many physical health factors associated with developmental disabilities. For some specific syndromes and diagnoses, these are inherent, such as poor heart function in people with Down syndrome. People with severe communication difficulties find it difficult to articulate their health needs, and without adequate support and education might not recognize ill health. Epilepsy, sensory problems (such as poor vision and hearing), obesity and poor dental health are over-represented in this population. Life expectancy among people with developmental disabilities as a group is estimated at 20 years below average, although this is improving with advancements in adaptive and medical technologies, and as people are leading healthier, more fulfilling lives, and some conditions (such as Freeman-Sheldon syndrome) do not impact life expectancy.

Attraction to disability or devotism is a sexualised interest in the appearance, sensation and experience of disability. It may extend from normal human sexuality into a type of sexual fetishism. Sexologically, the pathological end of the attraction tends to be classified as a paraphilia. (Note, however, that the very concept "paraphilia" continues to elude satisfactory definition and remains a subject of ongoing debate in both professional and lay communities) Other researchers have approached it as a form of identity disorder. The most common interests are towards amputations, prosthesis, and crutches.

There are a number of factors that could potentially contribute to the development of feeding and eating disorders of infancy or early childhood. These factors include:

- Physiological – a chemical imbalance effecting the child's appetite could cause a feeding or eating disorder.

- Developmental – developmental abnormalities in oral-sensory, oral-motor, and swallowing can impact the child's eating ability and elicit a feeding or eating disorder.

- Environmental – simple issues such as inconsistent meal times can cause a feeding or eating disorder. Giving the child food that they are not developmentally acquired for can also cause these disorders. Family dysfunction and sociocultural issues could also play a role in feeding or eating disorders.

- Relational – when the child is not securely attached to the mother, it can cause feeding interactions to become disturbed or unnatural. Other factors, such as parental emotional unavailability and parental eating disorders, can cause feeding and eating disorders in their children.

- Psychological and behavioral – these factors include one involving the child's temperament. Characteristics such as being anxious, impulsive, distracted, or strong-willed personality types are ones that could affect the child's eating and cause a disorder. The individual could have learned to reject food due to a traumatic experience such as choking or being force fed.

Intellectual disability in children can be caused by genetic or environmental factors. The individual could have a natural brain malformation or pre or postnatal damage done to the brain caused by drowning or a traumatic brain injury, for example. Nearly 30 to 50% of individuals with intellectual disability will never know the cause of their diagnosis even after thorough investigation.

Prenatal causes of intellectual disability include:

- Congenital infections such as cytomegalovirus, toxoplasmosis, herpes, syphilis, rubella and human immunodeficiency virus

- Prolonged maternal fever in the first trimester

- Exposure to anticonvulsants or alcohol

- Untreated maternal phenylketonuria (PKU)

- Complications of prematurity, especially in extremely low-birth-weight infants

- Postnatal exposure to lead

Single-gene disorders that result in intellectual disability include:

- Fragile X syndrome

- Neurofibromatosis

- Tuberous sclerosis

- Noonan's syndrome

- Cornelia de Lange's syndrome

These single-gene disorders are usually associated with atypical physical characteristics.

About 1/4 of individuals with intellectual disability have a detectable chromosomal abnormality. Others may have small amounts of deletion or duplication of chromosomes, which may go unnoticed and therefore, undetermined.

Mental health issues, and psychiatric illnesses, are more likely to occur in people with developmental disabilities than in the general population. A number of factors are attributed to the high incidence rate of dual diagnoses:

- The high likelihood of encountering traumatic events throughout their lifetime (such as abandonment by loved ones, abuse, bullying and harassment)

- The social and developmental restrictions placed upon people with developmental disabilities (such as lack of education, poverty, limited employment opportunities, limited opportunities for fulfilling relationships, boredom)

- Biological factors (such as brain injury, epilepsy, illicit and prescribed drug and alcohol misuse)

- Developmental factors (such as lack of understanding of social norms and appropriate behavior, inability of those around to allow/understand expressions of grief and other human emotions)

- External monitoring factor: all people with developmental disabilities that are in a federal- or state-funded residence require the residence to have some form of behavioral monitoring for each person with developmental disability at the residence. With this information psychological diagnoses are more easily given than with the general population that has less consistent monitoring.

- Access to health care providers: in the United States, all people with developmental disabilities that are in a federal- or state-funded residence require the residence to have annual visits to various health care providers. With consistent visits to health care providers more people with developmental disabilities are likely to receive appropriate treatment than the general population that is not required to visit various health care providers.

These problems are exacerbated by difficulties in diagnosis of mental health issues, and in appropriate treatment and medication, as for physical health issues.

Autistic enterocolitis is the name of a nonexistent medical condition proposed by discredited British gastroenterologist Andrew Wakefield when he suggested a link between a number of common clinical symptoms and signs which he contended were distinctive to autism. The existence of such an enterocolitis has been dismissed by experts as having "not been established". Wakefield's now-retracted and fraudulent report used inadequate controls and suppressed negative findings, and multiple attempts to replicate his results have been unsuccessful.

Reviews in the medical literature have found no link between the MMR vaccine and autism or with bowel disease.

Most of Wakefield's coauthors later retracted the conclusions of the original paper proposing the hypothesis, and the General Medical Council found Wakefield guilty of manipulating patient data and misreporting results. His work has been exposed as falsified and described as an "elaborate fraud".

Until the 1970s, autism was rarely accepted to be a distinctive diagnosis, but, following changes to the Diagnostic and Statistical Manual of the American Psychiatric Association it is diagnosed much more often. How much of this increase is due to greater diagnostic vigilance by doctors, changes in diagnostic categories, or an actual increase in prevalence, remains unclear. Late-onset autism cases are estimated at 25% and reported by sources including the "British Medical Journal" as not having changed in recent years.

Despite others describing common bowel features, there have been no peer reviewed studies yet published, as of 2006, corroborating the existence of "autistic enterocolitis"; other studies have explicitly refuted its existence. Thus, it is not generally accepted that the types of colitis diagnosed in autistic individuals are either unique to autism, or more common in autistic people than in the general population.

The term imbecile was once used by psychiatrists to denote a category of people with moderate to moderate intellectual disability, as well as a type of criminal. The word arises from the Latin word "imbecillus", meaning weak, or weak-minded. It included people with an IQ of 26–50, between "idiot" (IQ of 0–25) and "moron" (IQ of 51–70). In the obsolete medical classification (ICD-9, 1977), these people were said to have "moderate mental retardation" or "moderate mental subnormality" with IQ of 35–49.

The meaning was further refined into mental and moral imbecility. The concepts of "moral insanity", "moral idiocy"," and "moral imbecility", led to the emerging field of eugenic criminology, which held that crime can be reduced by preventing "feeble-minded" people from reproducing.

"Imbecile" as a concrete classification was popularized by psychologist Henry H. Goddard and was used in 1927 by United States Supreme Court Justice Oliver Wendell Holmes Jr. in his ruling in the forced-sterilization case "Buck v. Bell", 274 U.S. 200 (1927).

The concept is closely associated with psychology, psychiatry, criminology, and eugenics. However, the term "imbecile" quickly passed into vernacular usage as a derogatory term, and fell out of professional use in the 20th century in favor of "mental retardation".

In recent decades, the phrases "mental retardation", "mentally retarded", and "retarded" initially used in a medical manner, are regarded as derogatory and politically incorrect much like "moron", "imbecile", "cretin", "dolt" and "idiot", formerly used as scientific terms in the early 20th century. On October 5, 2010, President of the United States Barack Obama signed Senate Bill 2781, known as "Rosa's Law", which changed references in many Federal statutes that referred to "mental retardation" to refer instead to "intellectual disability".

Until the 1990s, it tended to be described mostly as acrotomophilia, at the expense of other disabilities, or of the wish by some to pretend or acquire disability. Bruno (1997) systematised the attraction as factitious disability disorder. A decade on, others argue that erotic target location error is at play, classifying the attraction as an identity disorder. In the standard psychiatric reference "Diagnostic and Statistical Manual of Mental Disorders", text revision (DSM-IV-tr), the fetish falls under the general category of "Sexual and Gender Identity Disorders" and the more specific category of paraphilia, or sexual fetishes; this classification is preserved in DSM-5.

Among children, the cause of intellectual disability is unknown for one-third to one-half of cases. About 5% of cases are inherited from a person's parents. Genetic defects that cause intellectual disability but are not inherited can be caused by accidents or mutations in genetic development. Examples of such accidents are development of an extra chromosome 18 (trisomy 18) and Down syndrome, which is the most common genetic cause. Velocariofacial syndrome and fetal alcohol spectrum disorders are the two next most common causes. However, doctors have found many other causes. The most common are:

- Genetic conditions. Sometimes disability is caused by abnormal genes inherited from parents, errors when genes combine, or other reasons. The most prevalent genetic conditions include Down syndrome, Klinefelter syndrome, Fragile X syndrome (common among boys), neurofibromatosis, congenital hypothyroidism, Williams syndrome, phenylketonuria (PKU), and Prader–Willi syndrome. Other genetic conditions include Phelan-McDermid syndrome (22q13del), Mowat–Wilson syndrome, genetic ciliopathy, and Siderius type X-linked intellectual disability () as caused by mutations in the "PHF8" gene (). In the rarest of cases, abnormalities with the X or Y chromosome may also cause disability. 48, XXXX and 49, XXXXX syndrome affect a small number of girls worldwide, while boys may be affected by 49, XXXXY, or 49, XYYYY. 47, XYY is not associated with significantly lowered IQ though affected individuals may have slightly lower IQs than non-affected siblings on average.

- Problems during pregnancy. Intellectual disability can result when the fetus does not develop properly. For example, there may be a problem with the way the fetus' cells divide as it grows. A pregnant person who drinks alcohol (see fetal alcohol spectrum disorder) or gets an infection like rubella during pregnancy may also have a baby with intellectual disability.

- Problems at birth. If a baby has problems during labor and birth, such as not getting enough oxygen, he or she may have developmental disability due to brain damage.

- Exposure to certain types of disease or toxins. Diseases like whooping cough, measles, or meningitis can cause intellectual disability if medical care is delayed or inadequate. Exposure to poisons like lead or mercury may also affect mental ability.

- Iodine deficiency, affecting approximately 2 billion people worldwide, is the leading preventable cause of intellectual disability in areas of the developing world where iodine deficiency is endemic. Iodine deficiency also causes goiter, an enlargement of the thyroid gland. More common than full-fledged cretinism, as intellectual disability caused by severe iodine deficiency is called, is mild impairment of intelligence. Certain areas of the world due to natural deficiency and governmental inaction are severely affected. India is the most outstanding, with 500 million suffering from deficiency, 54 million from goiter, and 2 million from cretinism. Among other nations affected by iodine deficiency, China and Kazakhstan have instituted widespread iodization programs, whereas, as of 2006, Russia had not.

- Malnutrition is a common cause of reduced intelligence in parts of the world affected by famine, such as Ethiopia.

- Absence of the arcuate fasciculus.

The IDEA requires that a student must exhibit one or more of the following characteristics over a long duration, and to a marked degree that adversely affects their educational performance, to receive an EBD classification:

- Difficulty to learn that cannot be explained by intellectual, sensory, or health factors.

- Difficulty to build or maintain satisfactory interpersonal relationships with peers and teachers.

- Inappropriate types of behavior (acting out against self or others) or feelings (expresses the need to harm self or others, low self-worth, etc.) under normal circumstances.

- A general pervasive mood of unhappiness or depression.

- A tendency to develop physical symptoms or fears associated with personal or school problems.

The term "EBD" includes students diagnosed with schizophrenia, but does not apply to students who are "socially maladjusted", unless it is determined that they also meet the criteria for an EBD classification.

Emotional and behavioral disorders (EBD; sometimes called emotional disturbance or serious emotional disturbance) refer to a disability classification used in educational settings that allows educational institutions to provide special education and related services to students that have poor social or academic adjustment that cannot be better explained by biological abnormalities or a developmental disability.

The classification is often given to students that need individualized behavior supports to receive a free and appropriate public education, but would not be eligible for an individualized education program under another disability category of the Individuals with Disabilities Education Act (IDEA).

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.

Drug diversion is a medical and legal concept involving the transfer of any legally prescribed controlled substance from the individual for whom it was prescribed to another person for any illicit use. The definition varies slightly among different jurisdictions, but the transfer of a controlled substance alone usually does not constitute a diversion, since certain controlled substances that are prescribed to a child are intended to be administered by an adult, as directed by a medical professional. The term comes from the "diverting" of the drugs from their original licit medical purpose. In some jurisdictions, drug diversion programs are available to first time offenders of diversion drug laws, which "divert" offenders from the criminal justice system to a program of education and rehabilitation.

Controlled prescription drug classes which are commonly diverted include:

- Benzodiazepines – including diazepam, temazepam, clonazepam, and alprazolam – prescription anxiolytics and sedatives

- Opioids – including morphine, hydrocodone, oxycodone and codeine – prescription pain medications

- Stimulants – amphetamine, methylphenidate, and modafinil – prescribed to treat ADHD and narcolepsy

- Z-drugs – including zolpidem (Ambien), Eszopiclone (Lunesta) – prescription sleep medications

According to the United States Department of Justice, "Most pharmaceuticals abused in the United States are diverted by doctor shopping, forged prescriptions, theft and, increasingly, via the Internet." To reduce the occurrence of pharmaceutical diversion by doctor shopping and prescription fraud, almost all states have established prescription monitoring programs (PMPs) that facilitate the collection, analysis, and reporting of information regarding pharmaceutical drug prescriptions.

The causes for learning disabilities are not well understood, and sometimes there is no apparent cause for a learning disability. However, some causes of neurological impairments include:

- Heredity and genetics

- Problems during pregnancy and birth

- Accidents after birth

Interventions include:

- Mastery model:

- Learners work at their own level of mastery.

- Practice

- Gain fundamental skills before moving onto the next level

- Note: this approach is most likely to be used with adult learners or outside the mainstream school system.

- Direct instruction:

- Emphasizes carefully planned lessons for small learning increments

- Scripted lesson plans

- Rapid-paced interaction between teacher and students

- Correcting mistakes immediately

- Achievement-based grouping

- Frequent progress assessments

- Classroom adjustments:

- Special seating assignments

- Alternative or modified assignments

- Modified testing procedures

- Quiet environment

- Special equipment:

- Word processors with spell checkers and dictionaries

- Text-to-speech and speech-to-text programs

- Talking calculators

- Books on tape

- Computer-based activities

- Classroom assistants:

- Note-takers

- Readers

- Proofreaders

- Scribes

- Special education:

- Prescribed hours in a resource room

- Placement in a resource room

- Enrollment in a special school for learning disabled students

- Individual education plan (IEP)

- Educational therapy

Sternberg has argued that early remediation can greatly reduce the number of children meeting diagnostic criteria for learning disabilities. He has also suggested that the focus on learning disabilities and the provision of accommodations in school fails to acknowledge that people have a range of strengths and weaknesses, and places undue emphasis on academic success by insisting that people should receive additional support in this arena but not in music or sports. Other research has pinpointed the use of resource rooms as an important—yet often politicized component of educating students with learning disabilities.