Delusional disorder is a psychotic illness characterized by non-bizarre delusions. These are fixed false beliefs that could potentially happen in real life, such as being spied on or poisoned.  The illness lacks many symptoms typically found in other types of psychoses, such as hallucinations, severe cognitive problems, mood instability or flatness.

Non-bizarre delusions are different from bizarre delusions, in which the patient believes a thought that could never be true (such as a man believing he is pregnant with an alien baby).

Some patients with delusional disorder may continue to function and socialize in a seemingly normal way. However, their inner world may cause quite a bit of emotional turmoil. The disorder does not affect the patient’s IQ.

According to the DSM, delusional disorder may be broken down into six subtypes:

  • Erotomanic: Believing someone, often rich or famous, is in love with them.
  • Grandiose: Believing in oneself as the most interesting, beautiful, perfect or intelligent person, etc. ever.
  • Jealous: Believing a partner is cheating.
  • Persecutory: Believing that someone is out to get them or someone they love.
  • Somatic: Believing they have a disease or other medical problem.
  • Mixed: Having more than one subtype.

A diagnosis of delusional disorder is is not given if the patient is also experiencing auditory or visual hallucinations. However, some patients may have olfactory or tactile hallucinations related to the content of their delusions. The delusions also cannot be due to the effects of a drug.

Treatment often involves atypical antipsychotic medication, such as risperidone (Risperdal), quetiapine (Seroquel) or olanzapine (Zyprexa). The patient may also receive cognitive therapy which has proven to be quite helpful.

Example: The patient was convinced that the CIA was watching his every move, even in the hospital bed.