What Is Paranoia?


Paranoia is an irrational feeling of being at risk of harm from others. Paranoid thoughts are often not shared by other people, and persist despite reassurances from others.2 

Some examples of paranoid thoughts include:

  • “I am being followed”
  • “Other people are talking about me”
  • “Other people are out to get me”
  • “I’m being targeted by the government”
  • “I’m being watched by a secret organisation”2

Paranoia, hallucination and delusion

Paranoid thoughts are also known as delusions, which is a type of psychosis. Psychosis is a mental health problem in which a person’s perception and interpretation of information and events are different from reality.

 Psychosis can be in the form of:

  • Delusions: The strong belief in something which is not consistent with reality6
  • Hallucinations: The perception, through any of our five senses, of something which does not exist. For example, hearing voices or seeing things which others do not see6

Both delusions and hallucinations can be distressing to experience. In some cases, people try to find explanations for their hallucinations by incorrectly attributing them to a cause, and these misattributions can lead to delusions.

Psychosis can be a symptom of mental illness. There is a range of mental disorders in which psychosis is often found, including:

  • Schizophrenia  - A severe and complex mental disorder in which people can lose touch with reality. Paranoid schizophrenia is a type of schizophrenia that is characterised by hallucinations and delusions of persecution or being under threat.4 People with schizophrenia may withdraw from others and have difficulty performing day-to-day tasks. However, they are not more likely to be violent than people without schizophrenia
  • Schizotypal personality disorder - A type of eccentric personality disorder characterised by odd behaviour or appearance, paranoid thoughts, and an unusual way of speaking. Hallucinations and delusions are usually less frequent and less prolonged than in schizophrenia4
  • Paranoid personality disorder - A disorder in which people strongly believe that others mean them harm, causing them to be excessively suspicious of others4 
  • Borderline personality disorder  - A disorder characterised by paranoid thoughts, sensitivity to rejection or social exclusion, and difficulties regulating emotions and maintaining interpersonal relationships.4 In borderline personality disorder, paranoid thoughts are typically about the untrustworthiness of others
  • Bipolar disorder - A mental health disorder in which people experience extreme moods.4 Patients with bipolar disorder have periods of extremely high mood (mania) followed by periods of very low mood (depression). In the past, this condition was known as manic depression
  • Narcissistic personality disorder - A disorder characterised by a high sense of self-importance and a need for recognition and admiration from others, or unstable self-esteem.4 People with narcissistic personality disorder often lack empathy. As paranoid thoughts can be triggered by having fragile self-esteem, paranoia is often seen in narcissistic personality disorder
  • Obsessive-compulsive disorder (OCD) - People with OCD experience obsessive thoughts or obsessions which are unwelcome and often cause feelings of anxiety.4 Patients typically engage in compulsive behaviours to relieve this anxiety, such as repeating movements, checking something multiple times, or cleaning. They may also have paranoid thoughts surrounding the idea that not performing a compulsive behaviour will cause themselves or someone else harm

Paranoia and phobias

phobia is an overwhelming fear of something, often with no cause. For example, claustrophobia is an extreme fear of confined spaces. The key similarity between paranoia and phobias is that they both involve an irrational fear of something. However, phobias tend to be specific, while paranoia is more general.4

Causes of paranoia

The exact cause of paranoia is unclear, but researchers have various theories to explain it. These theories can be classified into cognitive and evolutionary theories:

  • Cognitive theories - Cognitive theories assess the ways in which people perceive the world and process information. According to cognitive theories of paranoia, different cognitive biases can cause paranoia. Attentional bias is when people pay attention to only certain things or information, and disregard others, while interpretation bias is consistently interpreting information in a particular way3
  • Evolutionary theories - Evolutionary theories explain human behaviour by looking at how particular behaviours may have made individuals fitter for survival in an evolutionary context. An evolutionary perspective on paranoia is it evolved in response to the formation of social alliances and hierarchies. According to this theory, high levels of paranoia were likely useful for detecting threats to an alliance1

Researchers have also identified several factors that contribute to the development of paranoia. These include:

  • Early childhood experiences: Difficult experiences in childhood can cause people to perceive the world as hostile. Experiencing abuse or bullying can lead to mistrust of others into adulthood2
  • Belonging to a marginalised social group - Marginalised groups such as ethnic minorities and immigrants are more likely to experience paranoia, though this can be relieved by being surrounded by a higher proportion of members of the same marginalised group1
  • Mental health problems - Anxiety and depression, as well as psychotic disorders like schizophrenia, can increase the risk of developing paranoia2
  • Genetics - There is likely a genetic component to paranoia, though scientists are still unsure as to which genes are responsible2
  • Sleep deprivation - Lack of sleep can have a negative effect on mood, making negative thoughts and paranoia more likely to occur2
  • Substance abuse - Recreational drugs like cannabis, amphetamines, ecstasy, and cocaine are associated with paranoid thoughts2

Signs and symptoms of paranoia

People with paranoia often experience the following signs and symptoms: 

  • Persistent feelings of anxiety
  • Difficulty trusting other people
  • Difficulty maintaining relationships
  • Isolation and withdrawing from social situations
  • Handling criticism poorly
  • Feeling persecuted or threatened2

Management and treatment for paranoia

As severe paranoia is often part of a complex mental health disorder, it is usually necessary to first get a diagnosis and then treat the underlying disorder. 

Some helpful steps you can take include:

  • Consulting a GP: The first step is to talk to a GP about the paranoid thoughts and any difficulties it causes in daily life. The GP can then make a referral to a specialist who can make a diagnosis
  • Engaging in talking therapy: There are different types of talking therapy which can help manage paranoia, the most common being cognitive behavioural therapy (CBT).7 CBT works by challenging cognitive biases and considering alternative interpretations of events and distorted thoughts with more helpful ways of thinking
  • Making environmental changes: In situations where the physical or social environment makes paranoia more likely, changing or leaving the environment where possible can help to reduce paranoia. For example, moving to an area with a higher proportion of people from a similar background can reduce anxiety and paranoia in people from ethnic minority groups1


How common is paranoia?

Research shows that paranoia affects 2-15% of the general population.5

How is paranoia diagnosed?

Paranoia is often a part of other mental health disorders, and is not a diagnosis in itself. It is common in psychotic disorders like schizophrenia, and eccentric personality disorders such as paranoid personality disorder and schizotypal personality disorder.

How can I prevent paranoia?

People who feel that they are at risk of developing paranoia can use the following coping strategies:

  • Try to get enough sleep
  • Do mindfulness exercises
  • Seek out social support
  • Challenge paranoid thoughts

When should I call a doctor?

If paranoia is interfering with daily life, or is affecting relationships with friends and family, then it is advised to contact a doctor.


Paranoia is a persistent yet unsupported feeling of being persecuted or unsafe. Paranoid thoughts are a type of delusion, as they are not founded on evidence and are inconsistent with reality. Paranoia is not a diagnosis, but it can be part of different complex mental health disorders, such as schizophrenia, borderline personality disorder, bipolar disorder, narcissistic personality disorder, and obsessive-compulsive disorder. It is not clear what causes paranoia, but researchers have cognitive and evolutionary theories that try to explain it. Certain factors, such as early childhood experiences, social marginalisation, and genetics can increase the risk of paranoia. In cases where paranoia negatively interferes with life and relationships, it is advisable to consult a doctor and seek medical support.


  1. Raihani NJ, Bell V. An evolutionary perspective on paranoia. Nat Hum Behav [Internet]. 2019 Feb [cited 2023 Jan 21];3(2):114–21. Available from: https://www.nature.com/articles/s41562-018-0495-0
  2. https://www.mind.org.uk/information-support/types-of-mental-health-problems/paranoia/about-paranoia/
  3. Trotta A, Kang J, Stahl D, Yiend J. Interpretation bias in paranoia: a systematic review and meta-analysis. Clinical Psychological Science [Internet]. 2021 Jan [cited 2023 Jan 21];9(1):3–23. Available from: http://journals.sagepub.com/doi/10.1177/2167702620951552
  4. Diagnostic and statistical manual of mental disorders: DSM-5 [Internet]. 5th ed. Arlington, VA, Washington, D.C.: American Psychiatric Association, American Psychiatric Association; 2013 [cited 2023 Jan 21]. 947 p. Available from: http://www.PsychiatryOnline.org
  5. Freeman D. Delusions in the nonclinical population. Curr Psychiatry Rep [Internet]. 2006 May 1 [cited 2023 Jan 21];8(3):191–204. Available from: https://doi.org/10.1007/s11920-006-0023-1
  6. Rodríguez-Testal JF, Senín-Calderón C, Moreno R. Hallucinations and delusions as low-quality attributions: influencing factors and proposal for their analysis. Frontiers in Psychology [Internet]. 2021 [cited 2023 Jan 21];12. Available from: https://www.frontiersin.org/articles/10.3389/fpsyg.2021.533795
  7. Garety P, Ward T, Emsley R, Greenwood K, Freeman D, Fowler D, et al. Digitally supported CBT to reduce paranoia and improve reasoning for people with schizophrenia-spectrum psychosis: the SlowMo RCT. Efficacy and Mechanism Evaluation [Internet]. 2021 Aug 1 [cited 2023 Jan 21];8(11):1–90. Available from: https://doi.org/10.3310/eme08110 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Karabo Sibasa

Doctor of Philosophy - PhD, Psychology,The University of Manchester

Karabo has a BSc in Biochemistry and is currently doing a PhD in Psychology at the University of Manchester. She has a background in teaching and research, and is interested in health, science communication and education.

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