Adrift from reality: what are perceptual disturbances?

Adrift from reality: what are perceptual disturbances?

You may not feel as if you are real. The home you’ve always lived in is unfamiliar. Perhaps you hear strange voices that nobody else does, or mistake shadows for malign people lurking in the corner. You might suspect your family want to hurt you or the police are trying to track you down and lock you away. For someone in the grip of psychosis, these changes to perception of the outside world can be a terrifying reality, says Sarah Harrop.

Our perception is how we organise, identify and interpret sensory information – such as touch, sights, sounds and smells – to help us understand the world around us. Abnormalities or disturbances in perception are a feature of several mental health/neurological conditions, including schizophrenia, bipolar disorder, delirium, severe depression, epilepsy and dementia. But psychosis can also be triggered by a traumatic experience, stress, drug or alcohol misuse, side effects of medicines or head injuries. It can even occur after something as everyday and common as childbirth.

In the field of psychiatry, these experiences of ‘losing touch with reality’ are known as psychosis or psychotic episodes.

One estimate of the prevalence of psychosis from the 2014 Adult Psychiatric Morbidity Survey (APMS) found that around 0.5% of people aged over 16 in England had been diagnosed with a psychotic disorder (schizophrenia, schizoaffective disorder, or affective psychosis) in the preceding year. It’s also a complication of dementia, with a significant proportion (20 to 70 per cent by one estimate) of people living with dementia experiencing psychosis at some point.

According to a Public Health England report from 2016, psychosis is “one of the most life-impacting conditions in healthcare, and arguably the most significant in mental health in terms of poorest lifelong outcomes, greatest variation in access to evidence-based care and highest resultant costs.”

Psychosis affects people in different ways, with some experiencing it just once, others having short episodes throughout their lives and others living with it most of the time.

So-called perceptual abnormalities within psychosis are divided into three main categories: hallucinations, delusions and disorganised thinking and speech. Some of these are described by the DSM as positive symptoms, ie abnormal or unusual, and others are negative symptoms, meaning normal traits that most of us have are missing.


Hallucinations are sensory perceptions without any external stimulation which are believed to be absolutely real by the person experiencing them. Types of hallucination, which span all of the so-called sensory modalities, include:

  • Tactile sensations: these are felt without anything touching the person, for example feeling insects crawling on your skin when there are none.
  • Auditory hallucinations: including hearing voices or sounds that others don't, which can be positive and helpful or hostile and frightening.
  • Seeing things that other people don't: visual hallucinations such as faces, animals or religious figures as well as distortions in objects, for example appearing to sparkle or shine, or move in ways that they usually wouldn't. In the rare neuropsychological condition Alice in Wonderland Syndrome, objects and even body parts can appear smaller, bigger, closer, further away or distorted in shape, for example.
  • Olfactory hallucinations: experiencing tastes and smells with no apparent cause.
  • Pseudo-hallucinations: these are the same as a hallucination, but in this case the patient knows what they are perceiving is not real.

Lauren was diagnosed with schizoaffective disorder and bipolar disorder at the age of 25 and is the creator of the Living Well with Schizophrenia YouTube channel. Speaking firsthand about her own symptoms of schizophrenia, she describes some of her hallucinatory experiences:

“Primarily what I hear when I hear voices is mundane chatter around me, sometimes commentary on what I’m doing or the things around me. It’s hard to differentiate what I’m hearing from my own thoughts and my own experiences of reality. “

Lauren has also had some distressing olfactory hallucinations: “The smells that I smell are typically really bad smells that I can’t quite pinpoint what they are or where they’re coming from. Oftentimes I just assume that I stink and I get obsessed and self-conscious about that because I think that the bad smell I’m smelling is coming from me.”


Delusions are a psychopathology in which people have unshakeable beliefs in things that are not true or real. While of course many people have beliefs that others don’t share, a delusion is usually a belief that nobody else shares and which other experiences or perceptions show cannot be true.  

These might be delusions of grandeur, in which the person has an inflated perception of themselves. They may think they are a VIP or perhaps even a god, with superpowers that allow them to control the outcome of major sporting events, or the weather or the stock market.

Persecution or paranoid delusions are another common delusion in mental illnesses such as schizophrenia. Patients may believe that people are following them, or intend to harm them in some way or that they are being watched. These delusions can be frightening and can make the person experiencing them feel threatened or unsafe. A common delusion experienced by people with dementia, for example, is that when they are unable to find their clothes or possessions they are convinced that they’ve been stolen, which leads them to hide things in unusual places. In a vicious cycle, this causes more items to go ‘missing’.

There are also somatic delusions in which the person feels that some part of their body or its functioning is abnormal. They might see their reflection and feel like they are abnormally tall, for example, when in fact they are of a normal height.

Another category is erotomaniac delusions: those in which the person firmly believes others are in love with them or infatuated with them when they are not. 

Disorganised thinking and speech

People with mental disorders who are experiencing psychosis very often have trouble keeping their thoughts straight and clearly expressing what they are thinking; in fact disorganised thinking is one of the main symptoms of the disease. Some examples of thought process dysfunction include:

  • Racing thoughts and ‘flight of ideas’ – the person’s thoughts go through their head so fast that they feel out of control, and thoughts move quickly from idea to idea making links and connections between things in ways that other people would not. Their speech will often be fast, confusing and difficult to understand.
  • Distraction – ie beginning to talk about one thing and then completely changing topics mid-sentence, often as a result of nearby stimuli that interfere with the thought process.
  • Tangential thinking – moving from thought to thought without ever getting to the main point, with thoughts connected in a superficial or tangential way. Verywell Mind gives this example: "I really got mad as I was waiting in line at the grocery store. I cannot stand lines. Waiting and waiting. I waited for a long time to get my driver's licence. Driving these days is just crazy."
  • Incoherence – also referred to as ‘word salad’ this is where there are no discernible connections between a person’s spoken words, making it impossible to understand their thought process.
  • ‘Clang associations’ – choosing words based on sound (rhyming or pun associations) rather than their meaning. The person may also use made-up words and may speak in an unusual-sounding voice.

Perceptual impairments might also include illusions, where people misinterpret an external stimulus, such as mistaking a shadow for a person. Some people experience depersonalisation, when they feel they are no longer their ‘true’ self and are someone different or strange, and derealisation: a sense that the world around them is not a true reality.

How is psychosis treated and managed?

Treatment for psychosis can depend on the cause, but it will usually involve a mix of medicines and talking therapies.

Antipsychotic medicines

Antipsychotics can be effective for relieving some of the symptoms of psychosis. While they will usually reduce feelings of anxiety within a matter of hours it can take days or weeks to relieve psychotic symptoms such as hallucinations or delusional thoughts. These drugs work through modulation of the effects of neurotransmitters – the signalling chemicals in the brain – in particular dopamine, serotonin, noradrenaline and acetylcholine. Among many other functions in the brain, these neurotransmitters are involved in mood and emotions, control of the sleep-wake cycle, appetite and eating.

Older antipsychotics in the physician’s pharmacology toolbox – such as chlorpromazine, flupentixol and haloperidol – date back to the 1950s and mainly work by reducing the effect of dopamine in the brain; however these drugs tend to have side effects that cause problems with movement. Newer classes of drugs developed from the 1970s onwards have fewer side effects. Some of these newer medicines include: aripiprazole (Abilify), clozapine (Clozaril, Denzapine, Zaponex), olanzapine (Zypadhera, Zyprexa) and risperidone (Risperdal, Risperdal Consta).

Antipsychotics aren’t suitable or effective for everyone. Those with epilepsy or cardiovascular diseases must be closely monitored for side effects, for example. Neuropsychiatry clinicians may recommend that some people with psychosis should take antipsychotics for months or years, or even for the rest of their lives. Others may be able to gradually reduce their dosage and even stop taking them altogether if there is a marked improvement in their symptoms.  

Talking therapies

One-to-one talking therapies such as cognitive behavioural therapy (CBT) and family interventions (a form of therapy that may involve partners, family members and close friends) are also a mainstay for treating psychiatric illnesses such as mood disorders and psychosis. Social support with needs such as education, employment or accommodation for people with mental illness can also form a critical part of a person’s care plan.

Why inclusive education is critical for healthy societies

People with schizophrenia and other mental illnesses are all too often marginalised and can end up missing out on an education. Queen Margaret University’s MA Special and Inclusive Education programme is perfect for professionals working with people with complex learning needs seeking a greater depth of knowledge in inclusive education and its role in society. Viewing inclusive education through an interdisciplinary lens, students explore the role it plays in emancipation, liberation, and true democracy. Structural inequalities in both society and education, and their impact on educational outcomes, are key themes. Through this process, the MA teaches ways to address these inequalities in different contexts to make education inclusive.

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