Whatever the cause, the bodily related distortions can recur several times a day and may take some time to abate. Understandably, the person can become alarmed, frightened, and panic-stricken throughout the course of the hallucinations—maybe even hurt themselves or others around them. The symptoms of the syndrome themselves are not harmful and are likely to disappear with time.

Anaphia, also known as tactile anesthesia, is a medical symptom in which there is a total or partial absence of the sense of touch.

Anaphia is a common symptom of spinal cord injury and neuropathy.

The average age of the start of Alice in Wonderland syndrome is six but it is very normal for some to experience the syndrome from childhood to their late 20s. It is also thought that this syndrome is hereditary because many parents that have AIWS report their children having it as well.

Derealization (sometimes abbreviated as DR) is an alteration in the perception or experience of the external world so that it seems unreal. Other symptoms include feeling as though one's environment is lacking in spontaneity, emotional colouring, and depth. It is a dissociative symptom of many conditions.

Derealization is a subjective experience of unreality of the outside world, while depersonalization is sense of unreality in one's personal self, although most authors currently do not regard derealization (surroundings) and depersonalization (self) as separate constructs.

Chronic derealization may be caused by occipital–temporal dysfunction. These symptoms are common in the population, with a lifetime prevalence of up to 5% and 31–66% at the time of a traumatic event.

The prevalence of migraine and vertigo is 1.6 times higher in 200 dizziness clinic patients than in 200 age- and sex-matched controls from an orthopaedic clinic. Among the patients with unclassified or idiopathic vertigo, the prevalence of migraine was shown to be elevated. In another study, migraine patients reported 2.5 times more vertigo and also 2.5 more dizzy spells during headache-free periods than the controls.

MAV may occur at any age with a female:male ratio of between 1.5 and 5:1. Familial occurrence is not uncommon. In most patients, migraine headaches begin earlier in life than MAV with years of headache-free periods before MAV manifests.

In a diary study, the 1-month prevalence of MAV was 16%, frequency of MAV was higher and duration longer on days with headache, and MAV was a risk factor for co-morbid anxiety.

The term refers simplistically to a thought disorder shown from speech with a lack of observance to the main subject of discourse, such that a person whilst speaking on a topic deviates from the topic. Further definition is of speech that deviates from an answer to a question that is relevant in the first instance but deviates from the relevancy to related subjects not involved in a direct answering of the question. In the context of a conversation or discussion the communication is a response that is ineffective in that the form is inappropriate for adequate understanding. The person's speech seems to indicate that their attention to their own speech has perhaps in some way been overcome during the occurrence of cognition whilst speaking, causing the vocalized content to follow thought that is apparently without reference to the original idea or question; or the person's speech is considered evasive in that the person has decided to provide an answer to a question that is an avoidance of a direct answer.

Tangentiality as a medical symptom is a physical symptom observed in speech that tends to occur in situations where a person is experiencing high anxiety, as a manifestation of the psychosis known as "schizophrenia", in dementia or in states of delirium.

Antidepressants, including SSRIs, can cross the placenta and have the potential to affect the fetus and newborns, presenting a dilemma whether pregnant women should take antidepressants at all, and if they do, whether tapering them near the end of pregnancy could have a protective effect for the newborn.

Postnatal adaptation syndrome (PNAS) (originally called “neonatal behavioral syndrome”, “poor neonatal adaptation syndrome”, or "neonatal withdrawal syndrome") was first noticed in 1973 in newborns of mothers taking antidepressants; symptoms in the infant include irritability, rapid breathing, hypothermia, and blood sugar problems. The symptoms usually develop from birth to days after delivery and usually resolve within days or weeks of delivery.

The mechanisms of antidepressant withdrawal syndrome have not yet been conclusively identified. The leading hypothesis is that after the antidepressant is discontinued, there is a temporary deficiency in the brain of one or more essential neurotransmitters that regulate mood, such as serotonin, dopamine, norepinephrine, and gamma-aminobutyric acid, and since neurotransmitters are an interrelated system, dysregulation of one affects the others.

Derealization can accompany the neurological conditions of epilepsy (particularly temporal lobe epilepsy), migraine, and mild head injury. There is a similarity between visual hypo-emotionality, a reduced emotional response to viewed objects, and derealization. This suggests a disruption of the process by which perception becomes emotionally coloured. This qualitative change in the experiencing of perception may lead to reports of anything viewed being unreal or detached.

Derealization can also manifest as an indirect result of certain vestibular disorders such as labyrinthitis. This is thought to result from the experience of anxiety precipitated by the functional disparity that arises between the ability to reconcile external stimuli relative to motion and equilibrioception that are compromised by vestibular dysfunction with the internal perceptions and expectations regarding the physical environment.

An alternative explanation holds that a possible effect of vestibular dysfunction includes responses in the form of the modulation of noradrenergic and serotonergic activity due to a misattribution of vestibular symptoms to the presence of imminent physical danger resulting in the experience of anxiety or panic, which subsequently generate feelings of derealization.

Cannabis, psychedelics, dissociatives, antidepressants, caffeine, nitrous oxide, albuterol, and nicotine can all produce feelings resembling derealization, particularly when taken in excess. It can result from alcohol withdrawal or benzodiazepine withdrawal. Opiate withdrawal can also cause feelings of derealization.

Derealization can also be a symptom of severe sleep disorders and mental disorders like depersonalization disorder, borderline personality disorder, bipolar disorder, schizophrenia, dissociative identity disorder, and anxiety disorders.

Interoceptive exposure can be used as a means to induce derealization, as well as the related phenomenon depersonalization.

Depersonalization is also a direct symptom of Lyme disease as well as other tick-borne diseases. If depersonalization is suspected a blood-test is required in search of anti-bodies.

Comedown or crashing is the deterioration in mood that happens as a psychoactive drug, typically a stimulant, is either decreasing or is cleared from the blood and thus the cerebral circulation. The improvement and deterioration of mood (euphoria and dysphoria) are represented in the cognitive as high and low elevations; thus, after the drug has "elevated" the mood (a state known as a high), there follows a period of "coming back down," which often has a distinct character from withdrawal in stimulants. Generally, a comedown ("down", "low", sometimes "crash") can happen to anyone as a transient symptom, but in people who are dependent on the drug (especially those addicted to it), it is an early symptom of withdrawal and thus can be followed by others. Various drug classes, most especially stimulants and to a lesser degree opioids and sedatives, are subject to comedowns. A milder analogous mood cycle can happen even with blood sugar levels (thus sugar highs and sugar lows), which is especially relevant to people with diabetes mellitus and to parents and teachers managing children's behavior, as well as in adults with ADHD. Stimulant comedowns are unique in that they often appear very abruptly after a period of focus or high, and are typically the more intensely dysphoric phase of withdrawal than that following complete elimination from the bloodstream. Besides general dysphoria, this phase can be marked by frustration, anger, anhedonia, social withdrawal, and other symptoms characteristic to a milder mixed episode in bipolar disorder. Alertness and other general stimulant effects are still present.

Depersonalization has been described by some as a desirable state, particularly by those that have experienced it under the influence of mood-altering recreational drugs. It is an effect of dissociatives and psychedelics, as well as a possible side effect of caffeine, alcohol, amphetamine, and cannabis. It is a classic withdrawal symptom from many drugs.

Benzodiazepine dependence, which can occur with long-term use of benzodiazepines, can induce chronic depersonalization symptomatology and perceptual disturbances in some people, even in those who are taking a stable daily dosage, and it can also become a protracted feature of the benzodiazepine withdrawal syndrome.

Lieutenant Colonel Dave Grossman, in his book "", suggests that military training artificially creates depersonalization in soldiers, suppressing empathy and making it easier for them to kill other human beings.

Graham Reed (1974) noted that depersonalization occurs in relation to the experience of falling in love.

Atherosclerosis affects up to 10% of the Western population older than 65 years and for intermittent claudication this number is around 5%. Intermittent claudication most commonly manifests in men older than 50 years.

One in five of the middle-aged (65–75 years) population of the United Kingdom have evidence of peripheral arterial disease on clinical examination, although only a quarter of them have symptoms. The most common symptom is muscle pain in the lower limbs on exercise—intermittent claudication.

Empirical studies have found that the prognosis for conversion disorder varies widely, with some cases resolving in weeks, and others enduring for years or decades. There is also evidence that there is no cure for Conversion Disorder, and that although patients may go into remission, they can relapse at any point. Furthermore, many patients who are 'cured' continue to have some degree of symptoms indefinitely.

Information on the frequency of conversion disorder in the West is limited, in part due to the complexities of the diagnostic process. In neurology clinics, the reported prevalence of unexplained symptoms among new patients is very high (between 30 and 60%). However, diagnosis of conversion typically requires an additional psychiatric evaluation, and since few patients will see a psychiatrist it is unclear what proportion of the unexplained symptoms are actually due to conversion. Large scale psychiatric registers in the US and Iceland found incidence rates of 22 and 11 newly diagnosed cases per 100,000 person-years, respectively. Some estimates claim that in the general population, between 0.011% and 0.5% of the population have conversion disorder.

Formication is the medical term for a sensation that exactly resembles that of small insects crawling on (or under) the skin. It is one specific form of a set of sensations known as paresthesias, which also include the more common prickling, tingling sensation known as "pins and needles". Formication is a well documented symptom, which has numerous possible causes. The word is derived from "formica", the Latin word for ant.

Formication may sometimes be experienced as feelings of itchiness, tingling, pins and needles, burning, or even pain. When formication is perceived as itchiness, it may trigger the scratch reflex, and because of this, some people who are suffering from the sensation are at risk of causing skin damage through excessive scratching.

In some instances, static electricity can attract particulates to the skin and can also cause body hair to move, giving a sensation like insects crawling over the skin. However, in many cases no external trigger creates the sensation.

In rare cases, individuals become convinced that the sensation they are suffering is due to the presence of real insects on or under the skin. In these cases, patients have what is known as delusional parasitosis. They believe that their skin is inhabited by, or under attack by, small insects or similar parasites, despite repeated reassurances from physicians, pest control experts, and entomologists.

Treatment of migraine-associated vertigo is the same as the treatment for migraine in general.

Causes of formication include normal states such as onset of menopause (i.e. hormone withdrawal). Other causes are medical conditions such as pesticide exposure, mercury poisoning, diabetic neuropathy, skin cancer, syphilis, Lyme disease or herpes zoster (shingles). Formication can be a result of stimulant intoxication (e.g. methamphetamines, cocaine) or alcohol withdrawal in alcoholics (i.e. delirium tremens), and is often accompanied by visual hallucinations of insects (formicanopia). It can also occur as a symptom of benzodiazepine withdrawal, withdrawal from medication such as SSRI/SNRI antidepressants and Tramadol; and as a side effect of opioid analgesics.

A number of different causes contribute to this class of headache. Several common chemicals may be the culprit. Nitrite compounds dilate blood vessels, causing dull and pounding headaches with repeat exposure. Nitrite is found in dynamite, heart medicine and it is a chemical used to preserve meat (ergo these being known as "nitrite" or "hot dog" headaches). Eating foods prepared with monosodium glutamate (MSG) may thus result in headache. Acetaldehyde from alcohol may also cause a headache either acutely or after a number of hours (hangover).

Poisons, like carbon tetrachloride found in insecticides and lead can also cause headaches with repeated exposure. Ingesting lead paint or having contact with lead batteries can cause headaches, and so can exposure to materials that contain chemical solvents, like benzene, which are found in turpentine, spray adhesives, rubber cement, and inks. Headaches are also a symptom of carbon monoxide poisoning.

Drugs such as amphetamines can cause headaches as a side effect. Another type of drug-related headache occurs during withdrawal from long-term therapy with the antimigraine drug ergotamine tartrate. This is more commonly known as rebound headache, although some sources use the term interchangeably.

Scanning speech, like other ataxic dysarthrias, is a symptom of lesions in the cerebellum. It is a typical symptom of multiple sclerosis, and it constitutes one of the three symptoms of Charcot's neurologic triad.

Scanning speech may be accompanied by other symptoms of cerebellar damage, such as gait, truncal and limb ataxia, intention tremor, inaccuracies in rapidly repeated movements and sudden, abrupt nausea and vomiting. The handwriting of such patients may also be abnormally large.

BMS is benign (importantly, it is not a symptom of oral cancer), but as a cause of chronic pain which is poorly controlled, it can detriment quality of life, and may become a fixation which cannot be ignored, thus interfering with work and other daily activities. Two thirds of people with BMS have a spontaneous partial recovery six to seven years after the initial onset, but in others the condition is permanent. Recovery is often preceded by a change in the character of the symptom from constant to intermittent. No clinical factors predicting recovery have been noted.

If there is an identifiable cause for the burning sensation (i.e. primary BMS), then psychologic dysfunctions such as anxiety and depression often disappear if the symptom is successfully treated.

In about 50% of cases of burning mouth sensation no identifiable cause is apparent, these cases are termed (primary) BMS. Several theories of what causes BMS have been proposed, and these are supported by varying degrees of evidence, but none is proven.

As most people with BMS are postmenopausal women, one theory of the cause of BMS is of estrogen or progesterone deficit, but a strong statistical correlation has not been demonstrated. Another theory is that BMS is related to autoimmunity, as abnormal antinuclear antibody and rheumatoid factor can be found in the serum of more than 50% of persons with BMS, but these levels may also be seen in elderly people who do not have any of the symptoms of this condition. Whilst salivary flow rates are normal and there are no clinical signs of a dry mouth to explain a complaint of dry mouth, levels of salivary proteins and phosphate may be elevated and salivary pH or buffering capacity may be reduced.

Depression and anxiety are strongly associated with BMS. It is not known if depression is a cause or result of BMS, as depression may develop in any setting of constant unrelieved irritation, pain, and sleep disturbance. It is estimated that about 20% of BMS cases involve psychogenic factors, and some consider BMS a psychosomatic illness, caused by cancerophobia, concern about sexually transmitted infections, or hypochondriasis.

Chronic low-grade trauma due to parafunctional habits (e.g. rubbing the tongue against the teeth or pressing it against the palate), may be involved. BMS is more common in persons with Parkinson's disease, so it has been suggested that it is a disorder of reduced pain threshold and increased sensitivity. Often people with BMS have unusually raised taste sensitivity, termed hypergeusia ("super tasters"). Dysgeusia (usually a bitter or metallic taste) is present in about 60% of people with BMS, a factor which led to the concept of a defect in sensory peripheral neural mechanisms. Changes in the oral environment, such as changes in the composition of saliva, may induce neuropathy or interruption of nerve transduction. The onset of BMS is often spontaneous, although it may be gradual. There is sometimes a correlation with a major life event or stressful period in life. In women, the onset of BMS is most likely three to twelve years following menopause.

Headaches due to environmental causes are usually diagnosed by taking an exposure history.

Avolition, as a symptom of various forms of psychopathology, is the decrease in the motivation to initiate and perform self-directed purposeful activities. Such activities that appear to be neglected usually include routine activities, including hobbies, going to work and/or school, and most notably, engaging in social activities. A person experiencing avolition may stay at home for long periods of time, rather than seeking out work or peer relations.