There are few treatments for many types of hallucinations. However, for those hallucinations caused by mental disease, a psychologist or psychiatrist should be alerted, and treatment will be based on the observations of those doctors. Antipsychotic and atypical antipsychotic medication may also be utilized to treat the illness if the symptoms are severe and cause significant distress. For other causes of hallucinations there is no factual evidence to support any one treatment is scientifically tested and proven. However, abstaining from hallucinogenic drugs, stimulant drugs, managing stress levels, living healthily, and getting plenty of sleep can help reduce the prevalence of hallucinations. In all cases of hallucinations, medical attention should be sought out and informed of one's specific symptoms.

Treatment of any kind of complex visual hallucination requires an understanding of the different pathologies in order to correctly diagnose and treat. If a person is taking a pro-hallucinogenic medication, the first step is to stop taking it. Sometimes improvement will occur spontaneously and pharmacotherapy is not necessary. While there is not a lot of evidence of effective pharmacological treatment, antipsychotics and anticonvulsants have been used in some cases to control hallucinations. Since peduncular hallucinosis occurs due to an excess of serotonin, modern antipsychotics are used to block both dopamine and serotonin receptors, preventing the overstimulation of the lateral geniculate nucleus. The drug generically called carbamazepine increases GABA, which prevents the LGN from firing, thereby increasing the inhibition of the LGN. Regular antipsychotics as well as antidepressants can also be helpful in reducing or eliminating peduncular hallucinosis.

More invasive treatments include corrective surgery such as cataract surgery, laser photocoagulation of the retina, and use of optical correcting devices. Tumor removal can also help to relieve compression in the brain, which can decrease or eliminate peduncular hallucinosis. Some hallucinations may be due to underlying cardiovascular disease, so in these cases the appropriate treatment includes control of hypertension and diabetes. As described, the type of treatment varies widely depending on the causation behind the complex visual hallucinations.

One study from as early as 1895 reported that approximately 10% of the population experiences hallucinations. A 1996-1999 survey of over 13,000 people reported a much higher figure, with almost 39% of people reporting hallucinatory experiences, 27% of which daytime hallucinations, mostly outside the context of illness or drug use. From this survey, olfactory (smell) and gustatory (taste) hallucinations seem the most common in the general population.

Peduncular hallucinosis (PH), or Lhermitte's peduncular hallucinosis, is a rare neurological disorder that causes vivid visual hallucinations that typically occur in dark environments, and last for several minutes. Unlike some other kinds of hallucinations, the hallucinations that patients with PH experience are very realistic, and often involve people and environments that are familiar to the affected individuals. Because the content of the hallucinations is never exceptionally bizarre, patients can rarely distinguish between the hallucinations and reality.

In 1922, the French neurologist Jean Lhermitte documented the case of a patient who was experiencing visual hallucinations that were suggestive of localized damage to the midbrain and pons. After other similar case studies were published, this syndrome was labeled "peduncular hallucinosis."

The accumulation of additional cases by Lhermitte and by others influenced academic medical debate about hallucinations and about behavioral neurology.

Lhermitte provided a full account of his work in this area in his book "Les hallucinations: clinique et physiopathologie," which was published in Paris in 1951 by Doin publishing.

Contemporary researchers, with access to new technologies in medical brain imaging, have confirmed the brain localization of these unusual hallucinations.

In patients suffering from schizophrenia, grandiose and religious delusions are found to be the least susceptible to cognitive behavioral interventions. Cognitive behavioral intervention is a form of psychological therapy, initially used for depression, but currently used for a variety of different mental disorders, in hope of providing relief from distress and disability. During therapy, grandiose delusions were linked to patients' underlying beliefs by using inference chaining. Some examples of interventions performed to improve the patient's state were focus on specific themes, clarification of neologisms, and thought linkage. During thought linkage, the patient is asked repeatedly by the therapist to explain his/her jumps in thought from one subject to a completely different one.

Patients suffering from mental disorders that experience grandiose delusions have been found to have a lower risk of having suicidal thoughts and attempts.

In general, alcohol abusers with withdrawal symptoms, such as alcoholic hallucinosis, have a deficiency of several vitamins and minerals and their bodies could cope with the withdrawal easier by taking nutritional supplements. Alcohol abuse can create a deficiency of thiamine, magnesium, zinc, folate and phosphate as well as cause low blood sugar. However, several tested drugs have shown the disappearance of hallucinations. Neuroleptics and benzodiazepines showed normalization. Common benzodiazepines are chlordiazepoxide and lorazepam. It has been shown that management has been effective with a combination of abstinence from alcohol and the use of neuroleptics. It is also possible to treat withdrawal before major symptoms start to happen in the body. Diazepam and chlordiazepoxide have proven to be effective in treating alcohol withdrawal symptoms such as alcoholic halluciniosis. With the help of these specific medications, the process of withdrawal is easier to go through, making alcoholic hallucinosis less likely to occur.

Grandiose delusions (GD), delusions of grandeur, expansive delusions also known as megalomania are a subtype of delusion that occur in patients suffering from a wide range of psychiatric diseases, including two-thirds of patients in manic state of bipolar disorder, half of those with schizophrenia, patients with the grandiose subtype of delusional disorder, and a substantial portion of those with substance abuse disorders. GDs are characterized by fantastical beliefs that one is famous, omnipotent, wealthy, or otherwise very powerful. The delusions are generally fantastic and typically have a religious, science fictional, or supernatural theme. There is a relative lack of research into GD, in contrast to persecutory delusions and auditory hallucinations. About 10% of healthy people experience grandiose thoughts but do not meet full criteria for a diagnosis of GD.

Diagnosis is mainly based on symptoms. In a person with delirium tremens it is important to rule out other associated problems such as electrolyte abnormalities, pancreatitis, and alcoholic hepatitis.

The cause of alcoholic hallucinosis is unclear. It seems to be highly related to the presence of dopamine in the limbic system with the possibility of other systems. There are many symptoms that could possibly occur before the hallucinations begin. Symptoms include headache, dizziness, irritability, insomnia, and indisposition. Typically, alcoholic hallucinosis has a sudden onset.

Delirium tremens due to alcohol withdrawal can be treated with benzodiazepines. High doses may be necessary to prevent death. Amounts given are based on the symptoms. Typically the person is kept sedated with benzodiazepines, such as diazepam, lorazepam, chlordiazepoxide, or oxazepam.

In some cases antipsychotics, such as haloperidol may also be used. Older drugs such as paraldehyde and clomethiazole were formerly the traditional treatment but have now largely been superseded by the benzodiazepines.

Acamprosate is occasionally used in addition to other treatments, and is then carried on into long term use to reduce the risk of relapse. If status epilepticus occurs it is treated in the usual way. It can also be helpful to control environmental stimuli, by providing a well-lit but relaxing environment for minimizing distress and visual hallucinations.

Alcoholic beverages can also be prescribed as a treatment for delirium tremens, but this practice is not universally supported.

High doses of thiamine often by the intravenous route is also recommended.

A syndrome is a set of medical signs and symptoms occurring together, constitutes a particular disease or disorder. The word derives from the Greek σύνδρομον, meaning "concurrence". In some instances, a syndrome is so closely linked with a pathogenesis or cause that the words "syndrome", "disease", and "disorder" end up being used interchangeably for them. This is especially true of inherited syndromes. For example, Down syndrome, Wolf–Hirschhorn syndrome, and Andersen syndrome are disorders with known pathogeneses, so each is more than just a set of signs and symptoms, despite the "syndrome" nomenclature. In other instances, a syndrome is not specific to only one disease. For example, toxic shock syndrome can be caused by various toxins; premotor syndrome can be caused by various brain lesions; and premenstrual syndrome is not a disease but simply a set of symptoms.

If an underlying genetic cause is suspected but not known, a condition may be referred to as a genetic association (often just "association" in context). By definition, an association indicates that the collection of signs and symptoms occurs in combination more frequently than would be likely by chance alone.

Syndromes are often named after the physician or group of physicians that discovered them or initially described the full clinical picture. Such eponymous syndrome names are examples of medical eponyms. Recently, there has been a shift towards naming conditions descriptively (by symptoms or underlying cause) rather than eponymously, but the eponymous syndrome names often persist in common usage.

Multiple sclerosis is typically diagnosed based on the presenting signs and symptoms, in combination with supporting medical imaging and laboratory testing. It can be difficult to confirm, especially early on, since the signs and symptoms may be similar to those of other medical problems. The McDonald criteria, which focus on clinical, laboratory, and radiologic evidence of lesions at different times and in different areas, is the most commonly used method of diagnosis with the Schumacher and Poser criteria being of mostly historical significance.

Clinical data alone may be sufficient for a diagnosis of MS if an individual has had separate episodes of neurological symptoms characteristic of the disease. In those who seek medical attention after only one attack, other testing is needed for the diagnosis. The most commonly used diagnostic tools are neuroimaging, analysis of cerebrospinal fluid and evoked potentials. Magnetic resonance imaging of the brain and spine may show areas of demyelination (lesions or plaques). Gadolinium can be administered intravenously as a contrast agent to highlight active plaques and, by elimination, demonstrate the existence of historical lesions not associated with symptoms at the moment of the evaluation. Testing of cerebrospinal fluid obtained from a lumbar puncture can provide evidence of chronic inflammation in the central nervous system. The cerebrospinal fluid is tested for oligoclonal bands of IgG on electrophoresis, which are inflammation markers found in 75–85% of people with MS. The nervous system in MS may respond less actively to stimulation of the optic nerve and sensory nerves due to demyelination of such pathways. These brain responses can be examined using visual- and sensory-evoked potentials.

While the above criteria allow for a non-invasive diagnosis, and even though some state that the only definitive proof is an autopsy or biopsy where lesions typical of MS are detected, currently, as of 2017, there is no single test (including biopsy) that can provide a definitive diagnosis of this disease

In medicine a broad definition of syndrome is used, which describes a collection of symptoms and findings without necessarily tying them to a single identifiable pathogenesis. The more specific definition employed in medical genetics describes a subset of all medical syndromes.

The nerve conduction study usually provides useful information for making diagnosis. A CT scan is sometimes used to rule out some causes from the central nervous system.

A doctor will base his or her diagnosis on the symptoms the patient has and the results of tests, including:

- An X-ray

- Magnetic resonance imaging (MRI), which usually provides the most information

- Computed tomography (CT) scan

Many hospitals use the Clinical Institute Withdrawal Assessment for Alcohol (CIWA) protocol in order to assess the level of withdrawal present and therefore the amount of medication needed. When overuse of alcohol is suspected but drinking history is unclear, testing for elevated values of carbohydrate-deficient transferrin or gammaglutamyl transferase can help make the diagnosis of alcohol overuse and dependence more clear. The CIWA has also been shortened (now called the CIWA-Ar), while retaining its validity and reliability, to help assess patients more efficiently due to the life-threatening nature of alcohol withdrawal.

Other conditions that may present similarly include benzodiazepine withdrawal syndrome (a condition also mainly caused by GABA receptor adaptation).

If there aren't neurological symptoms (such as difficulties moving, loss of sensation, confusion, etc.) and there is no evidence of pressure on the spinal cord, a conservative approach may be taken such as:

- Drugs, such as aspirin, without steroids to relieve inflammation

- Cervical traction, in which the neck is pulled along its length, thus relieving pressure on the spinal cord

- Using a neck collar or cervical-thoracic suit

If there is pressure on the spinal cord or life-threatening symptoms are present, surgery is recommended.

While diagnostic criteria are not expected to change in the near future, work to develop biomarkers that help with diagnosis and prediction of disease progression is ongoing. New diagnostic methods that are being investigated include work with anti-myelin antibodies, and studies with serum and cerebrospinal fluid, but none of them has yielded reliably positive results.

At the current time, there are no laboratory investigations that can predict prognosis. Several promising approaches have been proposed including: interleukin-6, nitric oxide and nitric oxide synthase, osteopontin, and fetuin-A. Since disease progression is the result of degeneration of neurons, the roles of proteins showing loss of nerve tissue such as neurofilaments, tau, and N-acetylaspartate are under investigation. Other effects include looking for biomarkers that distinguish between those who will and will not respond to medications.

Improvement in neuroimaging techniques such as positron emission tomography (PET) or magnetic resonance imaging (MRI) carry a promise for better diagnosis and prognosis predictions, although the effect of such improvements in daily medical practice may take several decades. Regarding MRI, there are several techniques that have already shown some usefulness in research settings and could be introduced into clinical practice, such as double-inversion recovery sequences, magnetization transfer, diffusion tensor, and functional magnetic resonance imaging. These techniques are more specific for the disease than existing ones, but still lack some standardization of acquisition protocols and the creation of normative values. There are other techniques under development that include contrast agents capable of measuring levels of peripheral macrophages, inflammation, or neuronal dysfunction, and techniques that measure iron deposition that could serve to determine the role of this feature in MS, or that of cerebral perfusion. Similarly, new PET radiotracers might serve as markers of altered processes such as brain inflammation, cortical pathology, apoptosis, or remylienation. Antibiodies against the Kir4.1 potassium channel may be related to MS.

Benzodiazepines are effective for the management of symptoms as well as the prevention of seizures. Certain vitamins are also an important part of the management of alcohol withdrawal syndrome. In those with severe symptoms inpatient care is often required. In those with lesser symptoms treatment at home may be possible with daily visits with a health care provider.

"Seeing pink elephants" is a euphemism for drunken hallucination caused by alcoholic hallucinosis or delirium tremens. The term dates back to at least the early 20th century, emerging from earlier idioms about snakes and other creatures. An alcoholic character in Jack London's 1913 novel "John Barleycorn" is said to hallucinate "blue mice and pink elephants".

Medications offered can include the immunosuppressant prednisone, intravenous gamma globulin (IVIG), anticonvulsants such as gabapentin or Gabitril and antiviral medication, depending on the underlying cause..

In addition to treatment of the underlying disorder, palliative care can include the use of topical numbing creams, such as lidocaine or prilocaine. Care must be taken to apply only the necessary amount, as excess can contribute to the condition. Otherwise, these products offer extremely effective, but short-lasting, relief from the condition.

Paresthesia caused by stroke may receive some temporary benefit from high doses of Baclofen multiple times a day. HIV patients who self-medicate with cannabis report that it reduces their symptoms.

Paresthesia caused by shingles is treated with appropriate antiviral medication.

Diagnosis is by X-rays but preferably magnetic resonance imaging (MRI) of the whole spine. The most common causes of cord compression are tumors, but abscesses and granulomas (e.g. in tuberculosis) are equally capable of producing the syndrome. Tumors that commonly cause cord compression are lung cancer (non-small cell type), breast cancer, prostate cancer, renal cell carcinoma, thyroid cancer, lymphoma and multiple myeloma.

Surgical intervention is usually given to those individuals who have increased instability of their cervical spine, which cannot be resolved by conservative management alone. Further indications for surgery include a neurological decline in spinal cord function in stable patients as well as those who require cervical spinal decompression.

In many cases, individuals with CCS can experience a reduction in their neurological symptoms with conservative management. The first steps of these intervention strategies include admission to an intensive care unit (ICU) after initial injury. After entering the ICU, early immobilization of the cervical spine with a neck collar would be placed on the patient to limit the potential of further injury. Cervical spine restriction is maintained for approximately six weeks until the individual experiences a reduction in pain and neurological symptoms. Inpatient rehabilitation is initiated in the hospital setting, followed by outpatient physical therapy and occupational therapy to assist with recovery.

An individual with a spinal cord injury may have many goals for outpatient occupational and physiotherapy. Their level of independence, self-care, and mobility are dependent on their degree of neurological impairment. Rehabilitation organization and outcomes are also based on these impairments. The physiatrist, along with the rehabilitation team, work with the patient to develop specific, measurable, action-oriented, realistic, and time-centered goals.

With respect to physical therapy interventions, it has been determined that repetitive task-specific sensory input can improve motor output in patients with central cord syndrome. These activities enable the spinal cord to incorporate both supraspinal and afferent sensory information to help recover motor output. This occurrence is known as "activity dependent plasticity". Activity dependant plasticity is stimulated through such activities as: locomotor training, muscle strengthening, voluntary cycling, and functional electrical stimulation (FES) cycling

The association between pink elephants and alcohol is reflected in the name of various alcoholic drinks. There are various cocktails called "Pink Elephant", and The Huyghe Brewery put a pink elephant on the label of its Delirium Tremens beer.