• Paranoia is the irrational and persistent feeling that people are ‘out to get you’.
  • The three main types of paranoia include paranoid personality disorder, delusional (formerly paranoid) disorder and paranoid schizophrenia. 
  • Treatment aims to reduce paranoia and other symptoms and improve the person’s ability to function.

What is paranoia?

Paranoia is the irrational and persistent feeling that people are ‘out to get you’ or that you are the subject of persistent, intrusive attention by others. This unfounded mistrust of others can make it difficult for a person with paranoia to function socially or have close relationships. Paranoia may be a symptom of a number of conditions, including paranoid personality disorder, delusional (paranoid) disorder and schizophrenia. 

The cause of paranoia is unknown but genetics are thought to play a role. Treatment depends on the condition diagnosed as its cause, and may include treatment by psychological therapy or medication.


Paranoid symptoms may range from mild to severe. They depend on the cause but, generally, a person who is paranoid may: 

  • Be easily offended
  • Find it difficult to trust others
  • Not cope with any type of criticism
  • Assign harmful meanings to other people’s remarks
  • Be always on the defensive
  • Be hostile, aggressive and argumentative
  • Not be able to compromise
  • Find it difficult, if not impossible, to ‘forgive and forget’
  • Assume that people are talking ill of them behind their back
  • Be overly suspicious – for example, think that other people are lying or scheming to cheat them
  • Not be able to confide in anyone
  • Find relationships difficult 
  • Consider the world to be a place of constant threat
  • Feel persecuted by the world at large
  • Believe in unfounded ‘conspiracy theories’.

Three main types

Paranoia is associated with three principal conditions: 

  • Paranoid personality disorder – considered the mildest type. Most people with paranoid personality disorder function well despite their mistrust of the world. The attitudes and behaviours associated with this disorder, when they become obvious, are often discovered to have been present for much of the person’s life.
  • Delusional (paranoid) disorder – characterised by the dominance of one delusion (false belief) without any other sign of mental illness. The person’s behaviour depends on which delusion they have. For example, a person who has a delusion of persecution believes that other people are spying on them or plotting to harm them in some way. Stalking can be the result of delusional (paranoid) disorder – for example, the person believes they are in a relationship with a movie star they have never met. In another case, a person may imagine they have a terrible illness, despite repeated reassurance from doctors.
  • Paranoid schizophrenia – considered the most severe type. It is characterised by strange delusions, such as believing that one’s thoughts are being broadcast over the radio. Hallucinations, especially bizarre ones, are also common to the condition. A person with paranoid schizophrenia often finds the world confusing and functions poorly without treatment.

Causes are unclear

The causes of paranoia are unclear and depend on the condition with which it is associated. Theories include:

  • Genes – research is scanty and inconclusive. Some studies suggest a genetic link while others don’t. It is also unclear whether genetic predisposition to paranoia – if it exists – is inherited or not.
  • Brain chemistry – brain chemicals (neurotransmitters) form the basis of thoughts and feelings. Certain drugs such as cocaine, marijuana and amphetamines alter brain chemistry and can bring on paranoid thoughts, feelings and behaviours. This leads some researchers to believe that paranoia may be a biochemical disorder of the brain. The causes of this possible disorder are unknown. 
  • Traumatic life events – for example, abuse in childhood may distort the way a person thinks and feels throughout life. 
  • Stress reaction – some studies have found that paranoia is more common in people who have experienced severe and ongoing stress – for example, prisoners of war. How stress can trigger paranoia is unclear.
  • A combination of factors – it may be that a number of genetic and environmental factors working in combination cause paranoia.


The condition causing the paranoia can be difficult to diagnose because an exaggerated sense of mistrust is common to a range of mental disorders and also occurs in some people with dementia. Another difficulty is that a person who has paranoia may avoid doctors, hospitals and other medical settings for fear of being harmed. 

Diagnosis may include: 

  • Medical history
  • Physical examination
  • Assessment of symptoms
  • Psychological tests
  • Tests to rule out other psychiatric disorders that may be causing the symptoms.


While there is no absolute cure for the conditions that cause paranoia, treatment can help the person cope with their symptoms and live a happier, more productive life. Treatment depends on the type and severity of the condition but may include: 

  • Medications – anti-anxiety drugs or antipsychotic drugs can ease some of the symptoms. However, a person with paranoia may often refuse to take medication because they are afraid it will harm them.
  • Therapy – this can help the person to cope with their symptoms and may improve their ability to function. However, a person with paranoia is unlikely to talk openly and freely to a therapist, so progress can be extremely slow. 
  • Coping skills – other treatments aim to improve the person’s ability to function socially. Options may include relaxation therapy, techniques to reduce anxiety, and behaviour modification.
  • Hospital admission – in severe cases, the person may need to stay in hospital until the condition causing paranoia stabilises.

Where to get help

More information

Mental illness

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Mental illness explained

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This page has been produced in consultation with and approved by: Mental Health Foundation of Australia

Last updated: May 2020

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