Hallucinations are the sensory perception (i.e. hearing, seeing, feeling) of something that does not actually exist. This may involve hearing voices or seeing patterns, light, objects, and things that are not actually there. There are a number of things that commonly cause hallucinations, some are considered normal and others are considered a medical emergency. Hallucinations may be normal in some situations. For instance, when a person briefly sees or hears the voice of a loved one that recently died, these hallucinations may be a normal part of the grieving process.
Many hallucinations, however, are not normal and may require medical attention. Fever, sensory deprivation, delirium and dementia are common causes of hallucinations. Severe medical conditions like liver failure, kidney failure, and brain tumors may also cause hallucinations. Psychological disorders like schizophrenia, psychotic depression, and post-traumatic stress disorder may also cause hallucinations. Hallucinations that accompany mental disorders tend to be auditory, though some drugs also produce this type of hallucination.
Both recreational and therapeutic drugs can cause hallucinations. Recreational drugs are often sought specifically because they induce hallucinations. The use or withdrawal from marijuana, cocaine, LSD, psilocybin, crack, heroine, amphetamines, and alcohol can all produce hallucinations. Visual hallucinations, such as seeing patterns or objects, are most common with illicit drug use. Legal medications can also cause hallucinations. Antihistamines, anticonvulsants, antidepressants, antipsychotics, antibiotics, tranquillizers, pain killers (especially opioids), steroids, and cardiovascular medications have been associated with hallucinations.
Hallucinations can produce agitation, anxiety, paranoia, and fear in those who experience this detachment from reality. As a result a person who is hallucinating may become a danger to themselves or others. Hallucinations that are caused by medical conditions can indicate a serious problem that may quickly become an emergency situation. If you are with a person who is experiencing hallucinations, you may wish to seek medical help.
When a person presents with hallucinations, a physician will typically conduct a full medical examination and gather information about the individual's medical history. Blood tests may be conducted to determine the cause of the hallucinations. The physician may ask a number of questions as to the onset, duration, time of occurrence, and nature of hallucinations. S/he may also inquire about the feeling that accompanied or were prompted by the hallucinations. If certain life events, such as traumatic events or the loss of a loved one, have recently occurred in a patient's life, these may also be relevant to the experience of hallucinations.
There are medications available to reduce the occurrence of hallucinations in patients with psychological disorders. However, some of these drugs can actually produce or aggravate hallucinations. You may wish to discuss drug-induced hallucinations with your physician.