Types of Hallucinations

HyperMnesia and Disturbances of Perception

• HyperMnesia is an exaggerated degree of retention and recall, often seen in certain prodigies, obsessive-compulsive neurosis, paranoia, and mania.
• It can be elicited in a hypnotic trance.
• Macropsia is a condition in which objects appear larger than they really are, often seen in hysteria and delirium states.
• Micropsia is a condition in which objects appear smaller than they really are, often seen in hysteria and as an aura in some cases of epilepsy.

Hypochondriasis and Illusions

• Hypochondriasis is the unshakable belief that physical disease is present, despite all evidence to the contrary.
• Illusions are perceptual misinterpretations of real external sensory experiences.
• Examples of illusions include mistaking a mango tree shadow for a ghost at night.

Hallucinations

• Hallucinations are apparent perceptions of external objects with no corresponding real object.
• Types of hallucinations include:
  • Hypnagogic hallucination (false memory perception during sleep-wake transition)
  • Auditory hallucination (false auditory perception)
  • Visual hallucination (false visual perception)
  • Olfactory hallucination (false perception of smell)
  • Gustatory hallucination (false perception of taste)
  • Tactile haptic hallucination (false perception of touch)
  • Kinesthetic hallucination (false perception of movement or sensation)
  • Lilliputian hallucination (objects, usually people, appear greatly reduced in size, without a stimulus)

Disturbances of Affect

• Affect is the feeling tone, pleasurable or unpleasurable, that accompanies an idea.
• Types of disturbances of affect include:
  • Shallow or inadequate affect (emotional flatness)
  • Inappropriate affect (emotion does not correlate with the stimulus)
  • Labile affect (changeable)

Attitude and Paramnesia

• Attitude refers to the effective state with which a person habitually confronts their environment.
• Pleasurable affects include euphoria, elation, exaltation, and ecstasy.
• Euphoria is a feeling of emotional and physical well-being, but can be indicative of mental disorder if in an inappropriate setting.
• Paramnesia is a distortion of recall, often including false details or wrong temporal relationships.
• Fausse reconnaissance (false recognition) is the feeling of certainty that one is recalling accurately something that is patently inaccurate.

Distortions of Memory

• Retrospective falsification is a type of paramnesia, where false details, meanings, and recollections of real memory are created in response to emotional needs.
• Confabulation is the unconscious filling in of gaps in memory by imagined experience that the patient believes, although they have no basis in fact.
• Pseudo-reminiscence incorporates both confabulation and retrospective falsification.
• Déjà vu is an illusion of recognition in which a new situation is incorrectly regarded as a repetition of a previous memory.
• Jamais vu is a false feeling of unfamiliarity with a real situation that one has experienced.
• Déjà entendu is a false sense of familiarity with a comment never heard before.
• Déjà pensé is a false sense of familiarity with a thought never entertained before.