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Paranoia and Delusional Disorders

What is Paranoia?

Paranoia involves intense anxious or fearful feelings and thoughts often related to persecution, threat, or conspiracy. Paranoia occurs in many mental disorders, but is most often present in psychotic disorders. Paranoia can become delusions, when irrational thoughts and beliefs become so fixed that nothing (including contrary evidence) can convince a person that what they think or feel is not true. When a person has paranoia or delusions, but no other symptoms (like hearing or seeing things that aren't there), they might have what is called a delusional disorder.  Because only thoughts are impacted, a person with delusional disorder can usually work and function in everyday life, however, their lives may be limited and isolated.

What are the Signs of Paranoia?

Symptoms of paranoia and delusional disorders include intense and irrational mistrust or suspicion, which can bring on sense of fear, anger, and betrayal. Some identifiable beliefs and behaviors of individuals with symptoms of paranoia include mistrust, hypervigilence, difficulty with forgiveness, defensive attitude in response to imagined criticism, preoccupation with hidden motives, fear of being deceived or taken advantage of, inability to relax, or are argumentative.

What Causes Paranoia?

The cause of paranoia is a breakdown of various mental and emotional functions involving reasoning and assigned meanings. The reasons for these breakdowns are varied and uncertain. Some symptoms of paranoia relate to repressed, denied or projected feelings. Often, paranoid thoughts and feelings are related to events and relationships in a person's life, thereby increasing isolation and difficulty with getting help.

What is a Delusion?

A delusion is an odd belief that a person firmly insists is true despite evidence that it is not. Cultural beliefs that may seem odd, but are widely accepted do not fit the criteria for being a delusion. Two of the most common types of delusions are delusions of grandeur or persecutory delusions.

What is Delusional Disorder?

Delusional disorder is characterized by irrational or intense belief(s) or suspicion(s) which a person believes to be true. These beliefs may seem outlandish and impossible (bizarre) or fit within the realm of what is possible (non-bizarre). Symptoms must last for 1 month or longer in order for someone to be diagnosed with delusional disorder.

How are Paranoia and Delusions Treated?

Treatment of paranoia is usually via medication and cognitive behavioral therapy. The most important element in treating paranoia and delusional disorder, is building a trusting and collaborative relationship to reduce the impact of irrational fearful thoughts and improving social skills. It can be difficult to treat a person with paranoia since symptoms result in increased irritability, emotionally guardedness, and possible hostility. Often times, progress on paranoid delusions and especially delusional disorder is slow. Regardless of how slow the process, recovery and reconnection is possible.

To learn more visit:

Other Resources

American Psychiatric Association

National Institute of Mental Health Public Information and Communications Branch


Information compiled from:

“Mental Health Letter-Paranoia and Paranoid Disorders”. The Harvard Medical School Mental Health Letter. 74 Fenwood Rd, Boston MA 02115.

and Understanding Mental Disorders, Your Guide to DSM-5, American Psychiatric Association, 2015.


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