Lightheadedness is a common and typically unpleasant sensation of dizziness and/or a feeling that one may faint. The sensation of lightheadedness can be short-lived, prolonged, or, rarely, recurring. In addition to dizziness, the individual may feel as though his or her head is weightless. The individual may also feel as though the room is what causes the "spinning" or moving (vertigo) associated with lightheadedness. Most causes of lightheadedness are not serious and either cure themselves quickly, or are easily treated.

Keeping a sense of balance requires the brain to process a variety of information received from the eyes, the nervous system, and the inner ears. If the brain is unable to process these signals, such as when the messages are contradictory, or if the sensory systems are improperly functioning, an individual may experience lightheadedness or dizziness.

Episodes of vasovagal syncope are typically recurrent and usually occur when the predisposed person is exposed to a specific trigger. Before losing consciousness, the individual frequently experiences early signs or symptoms such as lightheadedness, nausea, the feeling of being extremely hot or cold (accompanied by sweating), ringing in the ears, an uncomfortable feeling in the heart, fuzzy thoughts, confusion, a slight inability to speak or form words (sometimes combined with mild stuttering), weakness and visual disturbances such as lights seeming too bright, fuzzy or tunnel vision, black cloud-like spots in vision, and a feeling of nervousness can occur as well. The symptoms may become more intense over several seconds to several minutes before the loss of consciousness (if it is lost). Onset usually occurs when a person is sitting up or standing.

When people lose consciousness, they fall down (unless prevented from doing so) and, when in this position, effective blood flow to the brain is immediately restored, allowing the person to regain consciousness. If the person does not fall into a fully flat, supine position, and the head remains elevated above the trunk, a state similar to a seizure may result from the blood's inability to return quickly to the brain, and the neurons in the body will fire off and generally cause muscles to twitch very slightly but mostly remain very tense. Fainting occurs with a loss of oxygen to the brain.

The autonomic nervous system's physiological state (see below) leading to loss of consciousness may persist for several minutes, so

- If sufferers try to sit or stand when they wake up, they may pass out again

- The person may be nauseated, pale, and sweaty for several minutes or hours

Typical triggers include:

- Prolonged standing

- Emotional stress

- Pain

- The sight of blood

- Time varying magnetic field (i.e. transcranial magnetic stimulation)

Lightheadedness can be simply (and most commonly) an indication of a temporary shortage of blood or oxygen to the brain due to a drop in blood pressure, rapid dehydration from vomiting, diarrhea, or fever. Other causes are: low blood sugar, hyperventilation, Postural Orthostatic Tachycardia Syndrome, panic attacks, and anemia. It can also be a symptom of many other conditions, some of them serious, such as heart problems (including abnormal heart rhythm or heart attack), respiratory problems such as pulmonary embolism, and also stroke, bleeding, and shock. If any of these serious disorders is present, the individual will usually have additional symptoms such as chest pain, a feeling of a racing heart, loss of speech or change in vision.

Many people, especially as they age, experience lightheadedness if they arise too quickly from a lying or seated position. Lightheadedness often accompanies the flu, hypoglycaemia, common cold, or allergies.

Dizziness could be provoked by the use of antihistamine drugs, like levocetirizine or by some antibiotics or SSRIs. Nicotine or tobacco products can cause lightheadedness for inexperienced users. Narcotic drugs, such as codeine can also cause lightheadedness.

Symptoms may include palpitations, feeling faint, sweating, shortness of breath, and chest pain. Episodes start and end suddenly.

Paroxysmal supraventricular tachycardia (PSVT) is a type of supraventricular tachycardia. Often people have no symptoms. Otherwise symptoms may include palpitations, feeling lightheaded, sweating, shortness of breath, and chest pain. Episodes start and end suddenly.

The cause is not known. Risk factors include alcohol, caffeine, nicotine, psychological stress, and Wolff-Parkinson-White syndrome which often is inherited from a person's parents. The underlying mechanism typically involves an accessory pathway that results in re-entry. Diagnosis is typically by an electrocardiogram (ECG) which shows narrow QRS complexes and a fast heart rhythm typically between 150 and 240 beats per minute.

Vagal maneuvers, such as the valsalva maneuver, are often used as the initial treatment. If not effective and the person has a normal blood pressure the medication adenosine may be tried. If adenosine is not effective a calcium channel blockers or beta blocker may be used. Otherwise synchronized cardioversion is the treatment. Future episodes can be prevented by catheter ablation.

About 2.3 per 1000 people have paroxysmal supraventricular tachycardia. Problems typically begin in those 12 to 45 years old. Women are more often affected than men. Outcomes in those who otherwise have a normal heart are generally good. An ultrasound of the heart may be done to rule out underlying heart problems.

The American Thoracic Society defines dyspnea as: "A subjective experience of breathing discomfort that consists of qualitatively distinct sensations that vary in intensity." Other definitions describe it as "difficulty in breathing", "disordered or inadequate breathing", "uncomfortable awareness of breathing", and as the experience of "breathlessness" (which may be either acute or chronic).

Anaemia that develops gradually usually presents with exertional dyspnea, fatigue, weakness, and tachycardia. It may lead to heart failure. Anaemia caused by low haemoglobin levels is often a cause of dyspnea. Menstruation, particularly if excessive, can contribute to anaemia and to consequential dyspnea in women. Headaches are also a symptom of dyspnea in patients suffering from anaemia. Some patients report a numb sensation in their head, and others have reported blurred vision caused by hypotension behind the eye due to a lack of oxygen and pressure; these patients have also reported severe head pains, many of which lead to permanent brain damage. Symptoms can include loss of concentration, focus, fatigue, language faculty impairment and memory loss.

Problems with balance can occur when there is a disruption in any of the vestibular, visual, or proprioceptive systems. Abnormalities in balance function may indicate a wide range of pathologies from causes like inner ear disorders, low blood pressure, brain tumors, and brain injury including stroke.

Many different terms are often used for dizziness, including lightheaded, floating, woozy, giddy, confused, helpless, or fuzzy. Vertigo, Disequilibrium and pre-syncope are the terms in use by most physicians and have more precise definitions.

Vertigo

Vertigo is the sensation of spinning or having the room spin about you. Most people find vertigo very disturbing and report associated nausea and vomiting.

Disequilibrium

Disequilibrium is the sensation of being off balance, and is most often characterized by frequent falls in a specific direction. This condition is not often associated with nausea or vomiting.

Presyncope

Pre-syncope is a feeling of lightheadedness or simply feeling faint. Syncope, by contrast, is actually fainting. A circulatory system deficiency, such as low blood pressure, can contribute to a feeling of dizziness when one suddenly stands up.

Problems in the skeletal or visual systems, such as arthritis or eye muscle imbalance, may also cause balance problems.

The behavioral symptoms are similar to those of an amphetamine, cocaine or caffeine overdose. Overstimulation of the central nervous system results in a state of hyperkinetic movement and unpredictable mental status including mania, rage and suicidal behavior.

Physical symptoms are more serious and include heart arrhythmias as well as outright heart attack or stroke in people who are at risk of coronary disease. Breathing is rapid and shallow while both pulse and blood pressure are dangerously elevated.

The symptoms of heliophobia depends on the person. Mild sufferers may feel uncomfortable, shaky, nauseated, or numb. Severe sufferers may feel anxious or suffer panic attacks. Other symptoms include heightened senses, lack of focus, feeling trapped, irregular heartbeat, air hunger, rapid breathing, parched mouth, sweating, muscle cramps, and physical discomfort that is not actually caused by bodily injury, but is a physical manifestation of the panic and fear that the heliophobic person experiences when exposed to light. This physical pain may be expressed, for example, as a phantom sensation of their skin burning under direct sunlight, even when it is visually apparent that their skin is not actually burning any more than healthy skin would as a result of sun exposure, but nonetheless still feels like real pain for the sufferer. However, other differential diagnoses like the rare genetic defect erythropoietic protoporphyria characterized by a severe burning sensation of all exposed skin areas without leading to immediate visible signs have to be excluded.

Because the adrenergic storm overlaps with so many other similar conditions, such as hypertensive crises, stimulant intoxication or overdose, or even panic attack, and because the treatments for these overlapping conditions are largely alike, it is not necessary to obtain a differential and definitive diagnosis before initiating treatment. However, analysis of the patient's medical history, checked against the possible causes of the adrenergic storm such as those above, should be done, because some adrenergic storms can be caused by serious underlying conditions. If a patient has an adrenergic storm and all or most of the other factors are ruled out, the adrenergic storm could lead to the discovery of a pheochromocytoma, which can become malignant. However, not all cases of adrenergic storm have an identifiable cause. Like a seizure, sometimes a patient has a single one, or perhaps a few, and then does not for the rest of their life. The mechanisms of idiopathic adrenergic storm are very poorly understood.

Serotonin syndrome, in which an excess of serotonin in the synapses causes a similar crisis of hypertension and mental confusion, could be confused with an adrenergic storm. The difference is that serotonin, being a tryptamine (non-catecholamine) involved in higher brain functions, can cause dangerous hypertension and tachycardia from its effects on the sympathetic nervous system, but as there are no serotonin receptors in the heart or blood vessels there are no direct effects on the heart. Thus, the presence of arrythmia, abnormal echocardiograms, or chest pain indicates an adrenergic crisis and rules out serotonin syndrome.

Holiday heart syndrome is an irregular heartbeat pattern presented in individuals who are otherwise healthy. Coined in 1978 the term is defined as "abnormal heart rhythms sometimes following excessive alcohol consumption; usually temporary".

Holiday heart syndrome can be the result of stress, dehydration, and drinking alcohol. It is sometimes associated with "binge drinking" common during the holiday season. The condition can also occur when individuals consume only moderate amounts of alcohol.

Irregular heartbeats can be serious. If palpitations continue for longer than a few hours patients should seek medical attention. Some arrhythmias associated with HHS after binge drinking can lead to sudden death, which may explain some of the sudden death cases commonly reported in alcoholics. Atrial fibrillation is the most common arrhythmia in holiday heart syndrome. Symptoms usually resolve themselves within 24 hours.

Holiday heart can also cause abnormal burning sensation whilst urinating and/or the feeling of passing blood similar to a kidney stone. This generally subsides in days or weeks.

Many people being treated for panic attacks begin to experience limited symptom attacks. These panic attacks are less comprehensive, with fewer than four bodily symptoms being experienced.

It is not unusual to experience only one or two symptoms at a time, such as vibrations in their legs, shortness of breath, or an intense wave of heat traveling up their bodies, which is not similar to hot flashes due to estrogen shortage. Some symptoms, such as vibrations in the legs, are sufficiently different from any normal sensation that they clearly indicate panic disorder. Other symptoms on the list can occur in people who may or may not have panic disorder. Panic disorder does not require four or more symptoms to all be present at the same time. Causeless panic and racing heartbeat are sufficient to indicate a panic attack.

When balance is impaired, an individual has difficulty maintaining upright orientation. For example, an individual may not be able to walk without staggering, or may not even be able to stand. They may have falls or near-falls. The symptoms may be recurring or relatively constant. When symptoms exist, they may include:

- A sensation of dizziness or vertigo.

- Lightheadedness or feeling woozy.

- Problems reading and difficulty seeing.

- Disorientation.

Some individuals may also experience nausea and vomiting, diarrhea, faintness, changes in heart rate and blood pressure, fear, anxiety, or panic. Some reactions to the symptoms are fatigue, depression, and decreased concentration. The symptoms may appear and disappear over short time periods or may last for a longer period.

Cognitive dysfunction (disorientation) may occur with vestibular disorders. Cognitive deficits are not just spatial in nature, but also include non-spatial functions such as object recognition memory. Vestibular dysfunction has been shown to adversely affect processes of attention and increased demands of attention can worsen the postural sway associated with vestibular disorders. Recent MRI studies also show that humans with bilateral vestibular damage undergo atrophy of the hippocampus which correlates with their degree of impairment on spatial memory tasks.

The main presentation of the syndrome is significant, acute pain in the chest, along with tenderness and some swelling of the cartilages affected, which is commonly palpable on examination. Perceived pain is often exacerbated with respiration. Although many times it can be extremely painful, to the point of being debilitating, Tietze's syndrome is considered to be a benign condition that generally resolves in 12 weeks. However, it can often be a chronic condition.

The associated chest pain may present similarly to angina pectoris, normally associated with heart disease, and can cause hyperventilation, anxiety or panic attacks, syncope (passing out), and temporary hypoesthesia (numbness) or paralysis.

Many cases of myocardial infarction (heart attack) patients have been re-considered and improperly diagnosed, due to the identical nature of the symptoms. In females, it is often misdiagnosed as mastalgia. Costochondritis symptoms are similar to Tietze's, the prime difference being that the pain radiates to the arms and shoulders in the latter.

Dysesthesia can generally be described as a class of neurological disorders. It can be further classified depending on where it manifests in the body, and by the type of sensation that it provokes.

Cutaneous dysesthesia is characterized by discomfort or pain from touch to the skin by normal stimuli, including clothing. The unpleasantness can range from a mild tingling to blunt, incapacitating pain.

Scalp dysesthesia is characterized by pain or burning sensations on or under the surface of the cranial skin. Scalp dysesthesia may also present as excessive itching of the scalp.

Occlusal dysesthesia, or "phantom bite", is characterized by the feeling that the bite is "out of place" (occlusal dystopia) despite any apparent damage or instability to dental or oromaxillofacial structures or tissue. Phantom bite often presents in patients that have undergone otherwise routine dental procedures. Short of compassionate counseling, evidence for effective treatment regimes is lacking.

People with panic attacks often report a fear of dying or heart attack, flashing vision, faintness or nausea, numbness throughout the body, heavy breathing and hyperventilation, or loss of body control. Some people also suffer from tunnel vision, mostly due to blood flow leaving the head to more critical parts of the body in defense. These feelings may provoke a strong urge to escape or flee the place where the attack began (a consequence of the "fight-or-flight response", in which the hormone causing this response is released in significant amounts). This response floods the body with hormones, particularly epinephrine (adrenaline), which aid it in defending against harm.

A panic attack is a response of the sympathetic nervous system (SNS). The most common symptoms include trembling, dyspnea (shortness of breath), heart palpitations, chest pain (or chest tightness), hot flashes, cold flashes, burning sensations (particularly in the facial or neck area), sweating, nausea, dizziness (or slight vertigo), light-headedness, hyperventilation, paresthesias (tingling sensations), sensations of choking or smothering, difficulty moving, and derealization. These physical symptoms are interpreted with alarm in people prone to panic attacks. This results in increased anxiety and forms a positive feedback loop.

Often, the onset of shortness of breath and chest pain are the predominant symptoms. People with a panic attack may incorrectly attribute them to a heart attack and thus trigger seeking treatment in an emergency room. However, since chest pain and shortness of breath are indeed hallmark symptoms of cardiovascular illnesses, including unstable angina and myocardial infarction (heart attack), especially in a person whose mental health status and heart health status are not known, attributing these pains to simple anxiety and not (also) a physical condition is a diagnosis of exclusion (other conditions must be ruled out first) until an electrocardiogram and a mental health assessment have been carried out.

Panic attacks are distinguished from other forms of anxiety by their intensity and their sudden, episodic nature. They are often experienced in conjunction with anxiety disorders and other psychological conditions, although panic attacks are not generally indicative of a mental disorder.

Sufferers may cover themselves with long, protective clothing or carry a sun parasol when going outdoors during the daytime, or simply never go outdoors at all when the sun is out, depending on the severity of the fear. Since sufferers stay indoors more than non-sufferers, it will make them more prone to becoming vitamin D deficient, as well as depression caused by a combination of vitamin D deficiency, isolation and feelings of alienation from other people, and a continuously dark environment. However, a vitamin deficiency can be helped by taking vitamin D supplements or by consuming vitamin D fortified foods.

A patient suffering from dysesthesia can find it to be unbearable at times. Dysesthetic burning has been called "Dante-esque" pain. The terminology used to describe it is usually interchangeable with descriptions of Hell in classic literature. It is the "bluntest" pain of which the human body is capable, and is characterized by the absence of accurate discriminative information.

Temperature change and heat both affect the sensation and raise the level of the steady pain. This pain upgrades with tonic light touch, phasic rubbing, or rough textures to become evoked pain.

The patient often cannot endure the touch of clothing. His or her entire life becomes an exercise in avoiding evoked pain. It causes difficulty in obtaining rest because bed-clothing contacts the skin. It drives the patient to a hysterical search for relief of the pain, which ends in some degree of resignation and frequent depression. Patients indicate that it has robbed them of their identity, since their values and mental priorities are so consumed by its avoidance.

Chronic anxiety is often associated with dysesthesia. Patients suffering from this anxiety may experience numbness or tingling in the face. In one study, those patients that were examined psychologically had symptoms of anxiety, depression, obsessive-compulsive personality disorder, or somatoform disorder.

Mental and emotional symptoms of lilapsophobia include

- Obsessive thoughts

- Difficulty thinking

- Feeling of unreality or being detached

- Fear of losing control or going crazy

- Anticipatory anxiety

- Terror

- Desire to flee or hide

Physical symptoms of lilapsophobia include

- Dizziness, shaking, palpitations, lightheaded, or faint

- Shortness of breath

- Accelerated heartbeat

- Chest pain or discomfort

- Shaking

- Feeling of choking

- Sweating

- Nausea

- Numbness or tingling sensations

Many lilapsophobes also suffer autophobia, fear of being alone. Sufferers often make arrangements with people they know to help soothe the fear.

Lovesickness refers to an informal affliction that describes negative feelings associated with rejection, unrequited love or the absence of a loved one. It can manifest as physical as well as mental symptoms. It is not to be confused with the condition of being lovestruck, which refers to the physical and mental symptoms associated with falling in love. The term lovesickness is rarely used in medical or psychological fields.

Many people believe lovesickness was created as an explanation for longings, but it can be associated with depression and various mental health problems.

Frank Tallis, a researcher in the topic of love and lovesickness, suggests in his 2005 article that lovesickness occurs when one is “truly, madly, deeply” in love and should be taken more seriously by medical professionals. Similarly, health experts agree that lovesickness has been known to kill and the diagnosis process should be taken more seriously. Symptoms of lovesickness are usually misdiagnosed for various other diseases or mental health issues such as OCD, this is because love sickness is less commonly recognized as a mental health issue in itself even though lovesickness is an extremely common, widespread disease.

Tallis includes a list of common symptoms of love sickness:

- Mania - an abnormally elevated mood or inflated self-esteem

- Depression

- Nausea

- Tearfulness

- Insomnia, which may lead to fatigue

- Lack of concentration

- Loss of appetite or overeating

- Hopelessness and/or helplessness

- Stress - high blood pressure, pain in chest and heart, acute insomnia; sometimes brought on by a "crush"

- Obsessive-Compulsive disorder - Preoccupation and hoarding valueless but superstitiously resonant items

- Psychologically created physical symptoms, such as upset stomach, change in appetite, insomnia, dizziness, and confusion

- Chronic neck pain, body tremors, intrusive thoughts, frequent flashbacks.

- Rapid mood swings

According to Tallis, many symptoms of being lovesick can be categorized under the DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) and the ICD-10 (International Classification of Diseases). Obsessive-Compulsive disorder (OCD) is a symptom of lovesickness because it includes a preoccupation, this would include constantly checking one's cellphone, Facebook, the hoarding of valueless items, etc. A further study conducted by Italian Psychiatrist Donatella Marazitti found that when people fall in love their estimated serotonin levels drop to levels found in patients with OCD, this level is significantly lower than that of an average or healthy person.

Necrophobia is a specific phobia which is the irrational fear of dead things (e.g., corpses) as well as things associated with death (e.g., coffins, tombstones, funerals, cemeteries). With all types of emotions, obsession with death becomes evident in both fascination and objectification. In a cultural sense, necrophobia may also be used to mean a fear of the dead by a cultural group, e.g., a belief that the spirits of the dead will return to haunt the living.

Symptoms include: shortness of breath, rapid breathing, irregular heartbeat, sweating, dry mouth and shaking, feeling sick and uneasy, psychological instability, and an altogether feeling of dread and trepidation. The sufferer may feel this phobia all the time. The sufferer may also experience this sensation when something triggers the fear, like a close encounter with a dead animal or the funeral of a loved one or friend. The fear may have developed when a person witnessed a death, or was forced to attend a funeral as a child. Some people experience this after viewing frightening media.

The fear can manifest itself as a serious condition. Treatment options include medication and therapy.

The word "necrophobia" is derived from the Greek "nekros" () for "corpse" and the Greek "phobos" () for "fear".

Sleep paralysis is when, during awakening or falling asleep, one is aware but unable to move. During an episode, one may hear, feel, or see things that are not there. It often results in fear. Episodes generally last less than a couple of minutes. It may occur as a single episode or be recurrent.

The condition may occur in those who are otherwise healthy, those with narcolepsy, or may run in families as a result of specific genetic changes. The condition can be triggered by sleep deprivation, psychological stress, or abnormal sleep cycles. The underlying mechanism is believed to involve a dysfunction in REM sleep. Diagnosis is based on a person's description. Other conditions that can present similarly include narcolepsy, atonic seizure, and hypokalemic periodic paralysis.

Treatment options for sleep paralysis have been poorly studied. People should generally be reassured that the condition is common and not serious. Other efforts that may be tried include sleep hygiene, cognitive behavioral therapy, and antidepressants.

Between 8% and 50% of people experience sleep paralysis at some time. About 5% of people have regular episodes. Males and females are affected equally. Sleep paralysis has been described throughout history. It is believed to have played a role in the creation of stories about alien abduction and other paranormal events.