Don Juanism or Don Juan syndrome is a non-clinical term for the desire, in a man, to have sex with many different female partners.

The name derives from the Don Juan of opera and fiction. The term satyriasis is sometimes used as a synonym for Don Juanism. The term has also been referred to as the male equivalent of nymphomania in women. These terms no longer apply with any accuracy as psychological or legal categories of psychological disorder.

Cryptomnesia occurs when a forgotten memory returns without it being recognized as such by the subject, who believes it is something new and original. It is a memory bias whereby a person may falsely recall generating a thought, an idea, a tune, or a joke, not deliberately engaging in plagiarism but rather experiencing a memory as if it were a new inspiration.

Sexual addiction, also known as sex addiction, is a state characterized by [[compulsive]] participation or engagement in [[Human sexual activity|sexual activity]], particularly [[sexual intercourse]], despite negative consequences. Proponents of a [[diagnostic model]] for sexual addiction, as defined here, consider it to be one of several sex-related disorders within an umbrella concept known as [[hypersexual disorder]]. The term "sexual dependence" is also used to refer to people who report being unable to control their [[sexual urges]], behaviors, or thoughts. Related models of pathological sexual behavior include [[hypersexuality]] (nymphomania and satyriasis), [[erotomania]], [[Don Juanism]] (or Don Juanitaism), and [[paraphilia]]-related disorders.

The concept of sexual addiction is contentious. There is considerable debate amongst [[psychiatrists]], psychologists, [[sexologist]]s, and other specialists whether compulsive sexual behavior constitutes an addiction, and therefore its classification and possible diagnosis. , sexual addiction is not a clinical diagnosis in either the [[Diagnostic and Statistical Manual of Mental Disorders|DSM]] or [[International Statistical Classification of Diseases and Related Health Problems|ICD]] medical classifications of diseases and medical disorders. Some argue that applying such concepts to normal behaviors such as sex, can be problematic, and suggest that applying medical models such as addiction to human sexuality can serve to [[Slut-shaming|pathologise normal behavior]] and cause harm

Neuroscientists, pharmacologists, molecular biologists, and other researchers in related fields have identified the [[transcription factor|transcriptional]] and [[epigenetic]] mechanisms of addiction [[pathophysiology]]. Diagnostic models, which use the pharmacological model of addiction (this model associates addiction with drug-related concepts, particularly [[physical dependence]], [[drug withdrawal]], and [[drug tolerance]]), do not currently include diagnostic criteria to identify sexual addictions in a clinical setting. In the brain disease model of addiction, which uses neuropsychological concepts to characterize addictions, sexual addictions are identifiable and well-characterized. In this model, [[addictive drugs]] are characterized as those which are both [[reinforcing]] and [[reward system|rewarding]]. Addictive behaviors (those which can induce a compulsive state) are similarly identified and characterized by their rewarding and reinforcing properties.

In "Sexual Addiction and Compulsivity", authors Taylor and Francis argue that: "Obsessive sexual behavior illness is defined by a continual pattern of failure to control intense, repetitive sexual impulses or urges."

According to a systematic review from 2014, prevalence rates of sexual addiction and related sexual disorders ranges from 3% to 6%.

Another theory suggests a possible relationship between histrionic personality disorder and antisocial personality disorder. Research has found 2/3 of patients diagnosed with histrionic personality disorder also meet criteria similar to those of the antisocial personality disorder, which suggests both disorders based towards sex-type expressions may have the same underlying cause. Women are hypersexualized in the media consistently, ingraining thoughts that the only way women are to get attention is by exploiting themselves, and when seductiveness isn't enough, theatricals are the next step in achieving attention. Men can just as well be flirtatious towards multiple women yet feel no empathy or sense of compassion towards them. They may also become the center of attention by exhibiting the "Don Juan" macho figure as a role-play.

Some family history studies have found that histrionic personality disorder, as well as borderline and antisocial personality disorders, tend to run in families, but it is unclear if this is due to genetic or environmental factors. Both examples suggest that predisposition could be a factor as to why certain people are diagnosed with histrionic personality disorder, however little is known about whether or not the disorder is influenced by any biological compound or is genetically inheritable. Little research has been conducted to determine the biological sources, if any, of this disorder.

Psychiatrist Carl Jung believed that Don Juanism was an unconscious desire of a man to seek his mother in every woman he encountered. However, he didn't see the trait as entirely negative; Jung felt that positive aspects of Don Juanism included heroism, perseverance and strength of will.

Jung argues that related to the mother-complex "are homosexuality and Don Juanism, and sometimes also impotence. In homosexuality, the son's entire heterosexuality is tied to the mother in an unconscious form; in Don Juanism, he unconsciously seeks his mother in every woman he meets...Because of the difference in sex, a son's mother-complex does not appear in pure form. This is the reason why in every masculine mother-complex, side by side with the mother archetype, a significant role is played by the image of the man's sexual counterpart, the anima."

One of Theodore Millon's five narcissist variations is the amorous narcissist which includes histrionic features. According to Millon, the Don Juan or Casanova of our times is erotic and exhibitionistic.

An idée fixe is a preoccupation of mind believed to be firmly resistant to any attempt to modify it, a fixation. The name originates from the French "idée", "idea" and "fixe", "fixed."

Approximately 1–3% of the general population may be diagnosed with HPD. Major character traits may be inherited, while other traits may be due to a combination of genetics and environment, including childhood experiences. This personality is seen more often in women than in men. It has typically been found that at least two thirds of persons with HPD are female, however there have been a few exceptions. Whether or not the rate will be significantly higher than the rate of women within a particular clinical setting depends upon many factors that are mostly independent of the differential sex prevalence for HPD. Those with HPD are more likely to look for multiple people for attention which leads to marital problems due to jealousy and lack of trust from the other party. This makes them more likely to become divorced or separated once married.

Hypersexuality may negatively impact an individual. The concept of hypersexuality as an addiction was started in the 1970s by former members of Alcoholics Anonymous who felt they experienced a similar lack of control and compulsivity with sexual behaviors as with alcohol. Multiple 12-step style self-help groups now exist for people who identify as sex addicts, including Sex Addicts Anonymous, Sexaholics Anonymous, Sex and Love Addicts Anonymous, and Sexual Compulsives Anonymous. Some hypersexuals may treat their condition with the usage of medication or any foods considered to be anaphrodisiacs. Other hypersexuals may choose a route of consultation, such as psychotherapy, self-help groups or counselling.

There is little consensus among experts as to the causes of hypersexuality. Some research suggests that some cases can be linked to biochemical or physiological changes that accompany dementia. Psychological needs also complicate the biological explanation, which identifies the temporal/frontal lobe of the brain as the area for regulating libido. Persons suffering from injuries to this part of the brain are at increased risk for aggressive behavior and other behavioral problems including personality changes and socially inappropriate sexual behavior such as hypersexuality. The same symptom can occur after unilateral temporal lobotomy. There are other biological factors that are associated with hypersexuality such as premenstrual changes, and the exposure to virilising hormones in childhood or in utero.

In research involving use of anti-androgens to reduce undesirable sexual behaviour such as hypersexuality, testosterone has been found to be necessary, but not sufficient, for sexual drive. Other proposed factors include a lack of physical closeness, and forgetfulness of the recent past.

Pathogenic overactivity of the dopaminergic mesolimbic pathway in the brain—forming either psychiatrically, during mania, or pharmacologically, as a side effect of dopamine agonists, specifically D-preferring agonists—is associated with various addictions and has been shown to result among some in overindulgent, sometimes hypersexual, behavior.

Cryptomnesia is more likely to occur when the ability to properly monitor sources is impaired. For example, people are more likely to falsely claim ideas as their own when they were under high cognitive load at the time they first considered the idea. Plagiarism increases when people are away from the original source of the idea, and decreases when participants are specifically instructed to pay attention to the origin of their ideas. False claims are also more prevalent for ideas originally suggested by persons of the same sex, presumably because the perceptual similarity of the self to a same-sex person exacerbates source confusion. In other studies it has been found that the timing of the idea is also important: if another person produces an idea immediately before the self produces an idea, the other's idea is more likely to be claimed as one's own, ostensibly because the person is too busy preparing for their own turn to properly monitor source information.

During the nineteenth century and early twentieth century, "monomania" appears in treatises on criminal law:

The aberrations of pyromania and kleptomania still are recognized as impulse control disorders or conduct disorders, and the notion of irresistible impulse still plays a legal role in the insanity defense.

Possibly the best example of the role of "idée fixe" in an insanity defense today is its use in identifying the paranoid personality disorder.

The extreme case of "paranoid psychosis" " ... includes preoccupation with delusional beliefs; believing that people are talking about oneself; believing one is being persecuted or being conspired against; and believing that people or external forces control one's actions."

The legal issues surrounding paranoia include judgment of competence to stand trial, conditions for involuntary hospitalization, involuntary medication, and a focus upon awareness or not of unreality at the moment when the defendant "snapped".

Afro-textured hair is the natural hair texture of certain populations in Africa, the African diaspora, Australia and Asia, which has not been altered by hot combs, flat irons or chemicals (through perming, relaxation or other straightening methods). Each strand of this hair type grows in a tiny, spring-like helix shape. The overall effect is such that, compared to straight, wavy or curly hair, afro-textured hair appears denser.

Concussions and other types of repetitive play-related head blows in American football have been shown to be the cause of chronic traumatic encephalopathy (CTE), which has led to player suicides and other debilitating symptoms after retirement, including memory loss, depression, anxiety, headaches, and also sleep disturbances.

The list of ex-NFL players that have either been diagnosed "post-mortem" with CTE or have reported symptoms of CTE continues to grow.

Clarence (2012) suggests that afro-textured hair may have initially evolved because of an adaptive need amongst humans' early hominid ancestors for protection against the intense UV radiation of the sun in Africa. With regard to the hypothesized recent African origin of modern humans, the author argues that afro-textured hair was the original hair texture of all modern humans prior to the "Out-of-Africa" migration that populated the rest of the globe. According to Clarence (2012), afro-textured hair may have been adaptive for the earliest modern humans in Africa because the relatively sparse density of such hair, combined with its elastic helix shape, results in an airy effect. The resulting increased circulation of cool air onto the scalp may have thus served to facilitate the body-temperature-regulation system of hominids while they lived on the open savannah. Afro-hair requires more moisture than straight hair and tends to shrink when dry. Instead of sticking to the neck and scalp when damp (as do straighter textures), unless completely drenched it tends to retain its basic springiness. The trait may have been retained and/or preferred among many anatomically modern populations in equatorial areas, such as Polynesians, Micronesians, Melanesians, Australoids and the Negrito, because of its contribution to enhanced comfort levels under tropical climate conditions.

Bletting is a process of softening that certain fleshy fruits undergo, beyond ripening. There are some fruits that are either sweeter after some bletting, such as sea buckthorn, or for which most varieties can be eaten raw only after bletting, such as medlars, persimmons, quince, service tree fruit, and wild service tree fruit ("chequers"). The rowan or mountain ash fruit must be bletted and cooked to be edible, to break down the toxic parasorbic acid (hexenollactone) into sorbic acid.

Chemically speaking, bletting brings about an increase in sugars and a decrease in the acids and tannins that cause the unripe fruit to be astringent.

Ripe medlars, for example, are taken from the tree, placed somewhere cool, and allowed to ripen for several weeks. In "Trees and Shrubs", horticulturist F. A. Bush wrote about medlars that "if the fruit is wanted it should be left on the tree until late October and stored until it appears in the first stages of decay; then it is ready for eating. More often the fruit is used for making jelly." Ideally, the fruit should be harvested from the tree immediately following a hard frost, which starts the bletting process by breaking down cell walls and speeding softening.

Once the process is complete, the medlar flesh will have broken down enough that it can be spooned out of the skin. The taste of the sticky, mushy substance has been compared to sweet dates and dry applesauce, with a hint of cinnamon. In "Notes on a Cellar-Book", the great English oenophile George Saintsbury called bletted medlars the "ideal fruit to accompany wine."

Albinism affects people of all ethnic backgrounds; its frequency worldwide is estimated to be approximately one in 17,000. Prevalence of the different forms of albinism varies considerably by population, and is highest overall in people of sub-Saharan African descent.

Certain ethnic groups and populations in isolated areas exhibit heightened susceptibility to albinism, presumably due to genetic factors. These include notably the Native American Kuna, Zuni and Hopi nations (respectively of Panama, New Mexico and Arizona); Japan, in which one particular form of albinism is unusually common; and Ukerewe Island, the population of which shows a very high incidence of albinism.

It is suggested that the early hominin evolved in East Africa around 3 million years ago. The dramatic phenotypic change from primate to early hominin is hypothesized to have involved the extreme loss of body hair – except for areas most exposed to UV radiation, such as the head – to allow for more efficient thermoregulation in the early hunter-gatherers. The skin that would have been exposed upon general body hair loss in these early hominins would have most likely been non-pigmented, reflecting the pale skin underlying the hair of our chimpanzee relatives. A positive advantage would have been conferred to early hominids inhabiting the African continent that were capable of producing darker skin – those who first expressed the eumelanin-producing MC1R allele – which protected them from harmful epithelium-damaging ultraviolet rays. Over time, the advantage conferred to those with darker skin may have led to the prevalence of darker skin on the continent. The positive advantage, however, would have had to be strong enough so as to produce a significantly higher reproductive fitness in those who produced more melanin. The cause of a selective pressure strong enough to cause this shift is an area of much debate. Some hypotheses include the existence of significantly lower reproductive fitness in people with less melanin due to lethal skin cancer, lethal kidney disease due to excess vitamin D formation in the skin of people with less melanin, or simply natural selection due to mate preference and sexual selection.

When comparing the prevalence of albinism in Africa to its prevalence in other parts of the world, such as Europe and the United States, the potential evolutionary effects of skin cancer as a selective force due to its effect on these populations may not be insignificant. The prevalence of albinism in some ethnic groups in sub-Saharan Africa is around 1 in 5,000, while in Europe and the US it is 1 in 20,000. It would follow, then, that there would be stronger selective forces acting on albino populations in Africa than on albino populations in Europe and the US. Rates as high as 1 in 1,000 have been reported for some populations in Zimbabwe and other parts of Southern Africa. In two separate studies in Nigeria, people with albinism were found to be of reproductively significant age more often than not. One study found that 89% of people diagnosed with albinism are between 0 and 30 years of age, while the other found that 77% of albinos were under the age of 20.

Concussions are proven to cause loss of brain function. This can lead to physical and emotional symptoms such as attention disorders, depression, headaches, nausea, and amnesia. These symptoms can last for days or week and even after the symptoms have gone, the brain still won't be completely normal. Players with multiple concussions can have drastically worsened symptoms and exponentially increased recovery time.

Researchers at UCLA have, for the first time, used a brain-imaging tool to identify a certain protein found in five retired NFL players. The presence and accumulation of tau proteins found in the five living players, are associated with Alzheimer's disease. Previously, this type of exam could only be performed with an autopsy. Scientists at UCLA created a chemical marker that binds to the abnormal proteins and they are able to view this with Positron Emission Tomography (PET) scan. Researcher at UCLA, Gary Small explains, "Providing a non-invasive method for early detection is a critical first step in developing interventions to prevent symptom onset and progression in CTE".

Chronic traumatic encephalopathy (CTE) is a neurodegenerative disease found in people who have had multiple head injuries. Symptoms may include behavioral problems, mood problems, and problems with thinking. This typically does not begin until years after the injuries. It often gets worse over time and can result in dementia. It is unclear if the risk of suicide is altered.

Most documented cases have occurred in athletes involved in contact sports such as football, wrestling, ice hockey, and soccer. Other risk factors include being in the military, prior domestic violence, and repeated banging of the head. The exact amount of trauma required for the condition to occur is unknown. Definitive diagnosis can only occur at autopsy. It is a form of tauopathy.

As of 2017 there is no specific treatment. Rates of disease have been found to be about 30% among those with a history of multiple head injuries. Population rates, however, are unclear. Research into brain damage as a result of repeated head injuries began in the 1920s, at which time the condition was known as "punch drunk". Changing the rules in some sports has been discussed as a means of prevention.

Symptoms of CTE, which occur in four stages, generally appear 8 to 10 years after an athlete experiences repetitive mild traumatic brain injury.

First-stage symptoms include attention deficit hyperactivity disorder as well as confusion, disorientation, dizziness, and headaches. Second-stage symptoms include memory loss, social instability, impulsive behavior, and poor judgment. Third and fourth stages include progressive dementia, movement disorders, hypomimia, speech impediments, sensory processing disorder, tremors, vertigo, deafness, depression and suicidality.

Additional symptoms include dysarthria, dysphagia, cognitive disorder such as amnesia, and ocular abnormalities, such as ptosis.

The condition manifests as dementia, or declining mental ability, problems with memory, dizzy spells or lack of balance to the point of not being able to walk under one's own power for a short time and/or Parkinsonism, or tremors and lack of coordination. It can also cause speech problems and an unsteady gait. Patients with DP may be prone to inappropriate or explosive behavior and may display pathological jealousy or paranoia.

Risk factors of progressive and severe thyroid-associated orbitopathy are:

- Age greater than 50 years

- Rapid onset of symptoms under 3 months

- Cigarette smoking

- Diabetes

- Severe or uncontrolled hyperthyroidism

- Presence of pretibial myxedema

- High cholesterol levels (hyperlipidemia)

- Peripheral vascular disease

The first symptom is typically diabetes mellitus, which is usually diagnosed around the age of 6. The next symptom to appear is often optic atrophy, the wasting of optic nerves, around the age of 11. The first signs of this are loss of colour vision and peripheral vision. The condition worsens over time, and people with optic atrophy are usually blind within 8 years of the first symptoms. Life expectancy of people suffering from this syndrome is about 30 years.

There is no known direct treatment. Current treatment efforts focus on managing the complications of Wolfram syndrome, such as diabetes mellitus and diabetes insipidus.