Chapter 3: Psychotic Disorders

PSYCHOSIS

Psychosis is a general term used to describe a distorted perception of reality. Poor reality testing may be accompanied by delusions, perceptual disturbances (illusions or hallucinations), and/or disorganized thinking/behavior. Psychosis can be a symptom of schizophrenia, mania, depression, delirium, and major neurocognitive disorder (i.e., dementia), and it can be substance or medication-induced.

Delusions

Delusions are fixed, false beliefs that persist despite evidence to the contrary and that do not make sense within the context of an individual's cultural background.

They can be categorized as either bizarre or nonbizarre. A nonbizarre delusion is a false belief that is plausible but is not true. Example: “The neighbors are spying on me by reading my e-mail.” A bizarre delusion is a false belief that is impossible. Example: “Aliens are spying on me through a Wi-Fi connection in my brain.”

Delusions can also be categorized by theme:

• Delusions of persecution/paranoid delusions: Irrational belief that one is being persecuted. Example: “The Central Intelligence Agency (CIA) is monitoring me and tapped my cell phone.”

• Delusions of reference: Belief that cues in the external environment are uniquely related to the individual. Example: “The TV characters are speaking directly to me.”

• Delusions of control: Includes thought broadcasting (belief that one's thoughts can be heard by others) and thought insertion (belief that outside thoughts are being placed in one's head).

• Delusions of grandeur: Belief that one has special powers beyond those of a normal person. Example: “I am the all-powerful son of God and I shall bring down my wrath on you if I don’t get my way.”

• Delusions of guilt: Belief that one is guilty or responsible for something. Example: “I am responsible for all the world's wars.”

• Somatic delusions: Belief that one has a certain illness or health condition. Example: A patient believing she is pregnant despite negative pregnancy tests and ultrasounds.

Perceptual Disturbances

• Illusion: Misinterpretation of an existing sensory stimulus (such as mistaking a shadow for an evil spirit).

• Hallucination: Sensory perception without an actual external stimulus.

  • Auditory: The most common modality experienced by patients with schizophrenia.

  • Visual: Occurs in schizophrenia and other psychotic disorders, but less common. May accompany drug intoxication, drug and alcohol withdrawal, or delirium.

  • Olfactory: Usually an aura associated with epilepsy.

  • Tactile: Usually secondary to drug intoxication (e.g., cocaine or psychostimulants) or alcohol withdrawal.

Differential Diagnosis of Psychosis

• Psychotic disorder due to another medical condition.

• Substance/Medication-induced psychotic disorder.

• Delirium/Major neurocognitive disorder (dementia).

• Bipolar disorder, manic/mixed episode.

• Major depressive disorder with psychotic features.

• Brief psychotic disorder.

• Schizophrenia.

• Schizophreniform disorder.

• Schizoaffective disorder.

• Delusional disorder.