Maureen Katushabe possessed a peculiar knack that scared her family into thinking that their daughter could be a psycho. She had the ability to hear voices other people around her couldn’t. The voices were sometimes from people who passed away and those voices would at times warn her about something that was to happen in the near future, and strangely some of it came to pass.

Katushabe’s experience wouldn’t be that strange if the voices or the departed approached her in her dreams, but what made the whole scenario a bit scary was that the voices came when she was conscious and not one of the people around her ever heard what she claimed she was hearing.

Some people would relate this condition to being psychotic, but medical experts say such behavior can be described as a state of hallucination.

But what are hallucinations and what would be the cause of such an odd condition?

The word ‘hallucination’ itself was introduced into the English language by the 17th century physician Sir Thomas Browne from the derivation of the Latin word ‘alucinari’ meaning ‘to wander in the mind’.

Hallucinating is an experience that involves the apparent perception of something not present, according to experts.

Dr Wilbur Bushara, a general practitioner, explains that hallucinations are not uncommon and that when they happen they are drawn from false sensory perceptions of things that are not there.

"When someone starts hearing or seeing something that does not actually exist, it is a hallucination. Such a condition can occur when one is mentally ill, or if one uses drugs or when they are suffering from a neurological condition,” he explains.

Bushara, however, says that anyone can experience hallucinations at some point in their life because the condition is not limited to people who are mentally or physically ill.

He says that most people are inclined to hallucinations, especially when they are under certain circumstances such as intense hunger or fear, the reason for instance one can think that they are seeing or hearing a voice of a loved one who passed away.

In her article ‘Inside The Mind’s Eye: This Is What Happens To Your Brain When You Hallucinate’, New York-based writer Lizette Borreli stresses the same issue that hallucinations are not limited to people who are mentally ill and that drug-induced hallucinations resulting from the use of amphetamines, cocaine, hallucinogens, steroids and types of marijuana can lead to spontaneous visual hallucinations.

Even those who withdraw from alcohol, sedatives hypnotics, or anxiolytics can also experience hallucinations, she notes.

Borreli notes that although hallucinations can involve any one of the senses including sight, sound, taste, smell or touch, the most common kind occur among schizophrenic patients who experience those which are auditory in nature.

"Hallucinations are considered to be a delicate and very complex regulation that scientists are just beginning to understand. They derive from false sensory perceptions of things that are not there, unlike illusions or delusions. Illusions are usually misperceptions of sensory things that are, in fact, there. Meanwhile, delusions are deeply fixed beliefs that are "solidified” by the individual despite the contrary information or evidence,” she states.

What it’s like to hallucinate

Dr Rachna Pande says that for one to understand that they were hallucinating, what they experience is intermittent.

"One would know in between the episodes that he has been imagining things. For others, whenever they have hallucinations, some family member or associates can always tell them that what they are seeing or hearing is imaginary,” she explains.

Dr Brendan Kelley, a neurologist at The Ohio State University Wexner Medical Centre in the US, explains that hallucinations, specifically "simple hallucinations” are more prevalent among the general population.

These hallucinations include lights, colors, lines, or simple geometric shape. These aspects can reflect abnormal activity anywhere along the visual pathways in the eye or the brain.

"When people have these simple geometrical hallucinations, the primary visual cortex is activated. This is the part of the brain that perceives edges and patterns. Images cannot be formed with the primary visual cortex. They generate when a higher part of the visual cortex is involved in the temporal lobe, specifically the fusiform gyrus,” he explains.

Understanding hallucinations

The most common form of hallucinations is auditory, according to Pande. This is the form of hallucination where one hears sounds that do not exist.

She says the next common type is visual, where one sees things which are not present.

"Apart from these, there is the olfactory type which involves smell and tactile hallucination which involves touch, though this is uncommon but it does occur. Rarely does one have taste hallucinations.

"Hallucinations are part of the manifestations of schizophrenia, a psychiatric disorder. One can have hallucinations as part of alcohol withdrawal syndrome. They can be due to a number of organic diseases as well. Any disease or disorder of the brain as some infection, trauma or tumour can cause hallucinations,” she says.

Pande also points out that the type of hallucination depends on the part of brain affected.

"Hallucinations can occur as part of Alzheimer’s disease or senile dementia, due to degeneration of brain substance.

"Many people experience visual hallucinations as part of a migraine attack, where they see coloured lights or halos which do not exist, "If hallucinations are irregular, that person would know in between the occurrence that what they were experiencing wasn’t real. For some, when they have hallucinations, it is someone close or one who was present at the time of the incident that can help explain that what they are experiencing isn’t real,” she says.

Pande, however, cautions that it is important to know whether hallucinations are due to some underlying organic disease or psychiatric problem.

"Tests like electroencephalogram (E.E.G.), C.T. scan of the brain and MRI of brain substance are done to identify a known organic cause,” she says.

Treating the underlying cause helps to treat the hallucinations as well. For those with schizophrenia or withdrawal syndromes, antipsychotic drugs and cognitive behavioural therapy along with extensive good counselling is done, Pande says.