The term feeble-minded was used from the late nineteenth century in Europe, the United States and Australasia for disorders later referred to as illnesses or deficiencies of the mind.

At the time, "mental deficiency" encompassed all degrees of educational and social deficiency. Within the concept of mental deficiency, researchers established a hierarchy, ranging from idiocy, at the most severe end of the scale; to imbecility, at the median point; and to feeble-mindedness at the highest end of functioning. The latter was conceived of as a form of high-grade mental deficiency.

The development of the ranking system of mental deficiency has been attributed to Sir Charles Trevelyan in 1876, and was associated with the rise of eugenics. The term and hierarchy had been used in that sense at least ten years previously. "Wild card" terms outside the established hierarchy such as "idiot savant", may have been used as connotations for varying degrees of autism.

Moron is a term once used in psychology and psychiatry to denote mild intellectual disability. The term was closely tied with the American eugenics movement. Once the term became popularized, it fell out of use by the psychological community, as it was used more commonly as an insult than as a psychological term. It is similar to imbecile and idiot.

Refusal of work is behavior which refuses to adapt to regular employment.

As actual behavior, with or without a political or philosophical program, it has been practiced by various subcultures and individuals. Radical political positions have openly advocated refusal of work. From within Marxism it has been advocated by Paul Lafargue and the Italian workerist/autonomists (e.g. Antonio Negri, Mario Tronti), the French ultra-left (e.g. Échanges et Mouvement); and within anarchism (especially Bob Black and the post-left anarchy tendency).

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.

The prognosis of SCT is unknown. In contrast, much is known about the adolescent and adult outcomes of children having ADHD. Those with SCT symptoms typically show a later onset of their symptoms than do those with ADHD, perhaps by as much as a year or two later on average. They have as much or more difficulty with academic tasks and far fewer social difficulties than do people having ADHD. They do not have the same risks for oppositional defiant disorder, conduct disorder, or social aggression and thus may have different life course outcomes compared to children with ADHD-HI and Combined subtypes who have far higher risks for these other "externalizing" disorders.

However, unlike ADHD, there are no longitudinal studies of children with SCT that can shed light on the developmental course and adolescent or adult outcomes of these individuals.

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".

In psychology, disinhibition is a lack of restraint manifested in disregard for social conventions, impulsivity, and poor risk assessment. Disinhibition affects motor, instinctual, emotional, cognitive, and perceptual aspects with signs and symptoms similar to the diagnostic criteria for mania. Hypersexuality, hyperphagia, and aggressive outbursts are indicative of disinhibited instinctual drives.

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.

Recent studies indicate that the symptoms of SCT in children form two dimensions: daydreamy-spacey and sluggish-lethargic, and that the former are more distinctive of the disorder from ADHD than the latter. This same pattern was recently found in the first study of adults with SCT by Barkley and also in more recent studies of college students. These studies indicated that SCT is probably not a subtype of ADHD but a distinct disorder from it. Yet it is one that overlaps with ADHD in 30–50% of cases of each disorder, suggesting a pattern of comorbidity between two related disorders rather than subtypes of the same disorder. Nevertheless, SCT is strongly correlated with ADHD inattentive and combined subtypes. According to a Norwegian study, "SCT correlated significantly with inattentiveness, regardless of the subtype of ADHD."

"Moron" was coined in 1910 by psychologist Henry H. Goddard from the Ancient Greek word "" ("moros"), which meant "dull" and used to describe a person with a mental age in adulthood of between 8 and 12 on the Binet scale. It was once applied to people with an IQ of 51–70, being superior in one degree to "imbecile" (IQ of 26–50) and superior in two degrees to "idiot" (IQ of 0–25). The word "moron", along with others including, "idiotic", "imbecilic", "stupid", and "feeble-minded", was formerly considered a valid descriptor in the psychological community, but it is now deprecated in use by psychologists.

In the obsolete medical classification (ICD-9, 1977), these people (morons and feeble-minded) were said to have "mild mental retardation", "mild mental subnormality" or "high-grade defect" with IQ 50–70.

Following opposition to Goddard's attempts to popularize his ideas, Goddard recanted his earlier assertions about the moron: "It may still be objected that moron parents are likely to have imbecile or idiot children. There is not much evidence that this is the case. The danger is probably negligible."

The earliest recorded use of the term in the English language dates from 1534, when it appears in one of the first English translations of the New Testament. A biblical injunction to "Comforte the feble mynded" is included in 1 Thessalonians 5:14.

A London "Times" editorial of November 1834 describes the long-serving former Prime Minister Lord Liverpool as a "feeble-minded pedant of office".

The Lance Armstrong doping case was a doping investigation that led to American former professional road racing cyclist Lance Armstrong being stripped of his seven Tour de France titles and his eventual admission to the doping.

Positive Behaviour Support (PBS) is a treatment approach that looks at the best way to work with each individual with disabilities. A behavioural therapist conducts a functional analysis of behaviour which helps to determine ways to improve the quality of life for the person and does not just deal with problem behaviour.

PBS also acknowledges the needs of support staff and includes strategies to manage crises when they arise. The following model is a brief guide to staff to remind them of key things to think about when planning support for a person with disabilities. There are two main objectives: reacting situationally when the behaviour occurs, and then acting proactively to prevent the behaviour from occurring.

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.

Foot binding was the custom of applying tight binding to the feet of young girls to modify the shape of their feet. The practice possibly originated among upper class court dancers during the Five Dynasties and Ten Kingdoms period in 10th century China, then became popular among the elite during the Song dynasty and eventually spread to all social classes by the Qing dynasty. Foot binding became popular as a means of displaying status (women from wealthy families, who did not need their feet to work, could afford to have them bound) and was correspondingly adopted as a symbol of beauty in Chinese culture. Foot binding limited the mobility of women, resulting in them walking in a swaying unsteady gait, although some women with bound feet working outdoor had also been reported. The prevalence and practice of foot binding varied in different parts of the country. Feet altered by binding were called lotus feet.

It has been estimated that by the 19th century, 40–50% of all Chinese women may have had bound feet, and up to almost 100% among upper class Han Chinese women. The Manchu Kangxi Emperor tried to ban foot binding in 1664 but failed. In the later part of the 19th century, Chinese reformers challenged the practice but it was not until the early 20th century that foot binding began to die out as a result of anti-foot-binding campaigns. Foot-binding resulted in lifelong disabilities for most of its subjects, and a few elderly Chinese women still survive today with disabilities related to their bound feet.

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.

Child abuse which encompasses physical, psychological and sexual abuse, as well as neglect has been shown to approximately triple the risk of an eating disorder. Sexual abuse appears to about double the risk of bulimia; however, the association is less clear for anorexia.

Some types of BDSM play include, but are not limited to:

- Animal roleplay

- Bondage

- Breast torture

- Cock and ball torture (CBT)

- Erotic electrostimulation

- Edgeplay

- Flogging

- Golden showers (urinating)

- Human furniture

- Japanese bondage

- Medical play

- Paraphilic infantilism

- Predicament bondage

- Pussy torture

- Sexual roleplay

- Spanking

- Suspension

- Torture

- Tickle torture

- Wax play

Eating disorders result in about 7,000 deaths a year as of 2010, making them the mental illnesses with the highest mortality rate.

One study in the United States found a higher rate in college students who are transgender.

The secondary disabilities of FAS are those that arise later in life secondary to CNS damage. These disabilities often emerge over time due to a mismatch between the primary disabilities and environmental expectations; secondary disabilities can be ameliorated with early interventions and appropriate supportive services.

Six main secondary disabilities were identified in a University of Washington research study of 473 subjects diagnosed with FAS, PFAS (partial fetal alcohol syndrome), and ARND (alcohol-related neurodevelopmental disorder):

- Mental health problems: Diagnosed with ADHD, Clinical Depression, or other mental illness, experienced by over 90% of the subjects

- Disrupted school experience: Suspended or expelled from school or dropped out of school, experienced by 60% of the subjects (age 12 and older)

- Trouble with the law: Charged or convicted with a crime, experienced by 60% of the subjects (age 12 and older)

- Confinement: For inpatient psychiatric care, inpatient chemical dependency care, or incarcerated for a crime, experienced by about 50% of the subjects (age 12 and older)

- Inappropriate sexual behavior: Sexual advances, sexual touching, or promiscuity, experienced by about 50% of the subjects (age 12 and older)

- Alcohol and drug problems: Abuse or dependency, experienced by 35% of the subjects (age 12 and older)

Two additional secondary disabilities exist for adults:

- Dependent living: Group home, living with family or friends, or some sort of assisted living, experienced by 80% of the subjects (age 21 and older)

- Problems with employment: Required ongoing job training or coaching, could not keep a job, unemployed, experienced by 80% of the subjects (age 21 and older)

The only certain way to prevent FAS is to avoid drinking alcohol during pregnancy. In the United States, the Surgeon General recommended in 1981, and again in 2005, that women abstain from alcohol use while pregnant or while planning a pregnancy, the latter to avoid damage even in the earliest stages (even weeks) of a pregnancy, as the woman may not be aware that she has conceived. In the United States, federal legislation has required that warning labels be placed on all alcoholic beverage containers since 1988 under the Alcoholic Beverage Labeling Act.

There is some controversy surrounding the "zero-tolerance" approach taken by many countries when it comes to alcohol consumption during pregnancy. The assertion that moderate drinking causes FAS is said to lack strong evidence and, in fact, the practice of equating a responsible level of drinking with potential harm to the fetus may have negative social, legal, and health impacts. In addition, special care should be taken when considering statistics on this disease, as prevalence and causation is often linked with FASD, which is more common and causes less harm, as opposed to FAS.

International human rights law does not recognize the refusal of work or right not to work by itself except the right to strike. However the Abolition of Forced Labour Convention adopted by International Labour Organization in 1957 prohibits all forms of forced labour.

Underwear fetishism is a sexual fetishism relating to undergarments, and refers to preoccupation with the sexual excitement of certain types of underwear, including panties, stockings, pantyhose, bras, or other items. Some people experience sexual excitement from wearing, while others get their excitement when observing or handling the underwear worn by another, or watching somebody putting underwear on/taking it off. Some may steal used underwear to get satisfaction. Not only does this include physical contact with the garment(s), or their wearers, but also includes arousal by printed or electronic image with depictions of underwear.

Underwear fetishism is not considered as paraphilia unless it causes distress or serious problems for the person or those associated with them.

Internet addiction disorder, more commonly called problematic Internet use (PIU), refers to excessive Internet use that interferes with daily life.

The most common problem with bound feet was infection. Despite the amount of care taken in regularly trimming the toenails, they would often in-grow, becoming infected and causing injuries to the toes. Sometimes for this reason the girl's toenails would be peeled back and removed altogether. The tightness of the binding meant that the circulation in the feet was faulty, and the circulation to the toes was almost cut off, so any injuries to the toes were unlikely to heal and were likely to gradually worsen and lead to infected toes and rotting flesh. The necrosis of the flesh would also initially give off a foul odour, and later the smell may come from various microorganisms that colonized the folds.

If the infection in the feet and toes entered the bones, it could cause them to soften, which could result in toes dropping off; although, this was seen as a benefit because the feet could then be bound even more tightly. Girls whose toes were more fleshy would sometimes have shards of glass or pieces of broken tiles inserted within the binding next to her feet and between her toes to cause injury and introduce infection deliberately. Disease inevitably followed infection, meaning that death from septic shock could result from foot-binding, and a surviving girl was more at risk for medical problems as she grew older. It is thought that as many as 10% of girls may have died from gangrene and other infections due to footbinding.

At the beginning of the binding, many of the foot bones would remain broken, often for years. However, as the girl grew older, the bones would begin to heal. Even after the foot bones had healed, they were prone to re-breaking repeatedly, especially when the girl was in her teenage years and her feet were still soft. Bones in the girls' feet would often be deliberately broken again in order to improve the size or the shape of the feet. This was especially the case with the toes, as small toes were especially desirable. Older women were more likely to break hips and other bones in falls, since they could not balance securely on their feet, and were less able to rise to their feet from a sitting position. Other issues that might arise from foot binding included paralysis and muscular atrophy.