Steven Lippmann, M.D.

On occasion one encounters patients who misidentify people or things in their environment. It is characterized by delusional degrees of erroneous recognition. Such psychotic manifestations can be a part of traditional mental illnesses in psychiatric practice (e.g., Capgras syndrome). However, the development of misrecognitions may also be associated with non-psychiatric etiologies.

The pathology includes neurological conditions and much more rarely, metabolic dysfunction or toxicities. It is thus important to comprehensively evaluate patients with clinical misidentifications to establish a correct diagnosis, which guides proper treatment. The brain dysfunction may involve disruption between the inferior temporal cortex where recognition occurs and the amygdala which yields the emotional response.

Neurological Causes of Misidentification

• Post-ictal states – spontaneous or induced seizures, e.g., electroconvulsive therapy
• Dementias – Alzheimer’s, Parkinson’s, Lewy body, or vascular dementias, etc.
• Brain disease – trauma, infarction, ischemia, multiple sclerosis, neoplasm, aneurysm, attention deficit disorder

Metabolic/Toxic Causes of Misidentification

• Endocrinopathies (rare) – e.g., diabetes, hypothyroidism, etc.
• Various toxicities (rare) – e.g., alcohol, ketamine, or still more rarely others

Psychiatric Misidentifications *

• Capgras syndrome – an imposter has replaced another person, animal, or object
• Fregoli syndrome – one person’s appearance changes over time
• Cotard delusion – that one is dead or that their body parts are absent or rotting
• Reduplicative paramnesia – someone or some place is duplicated
• Mirrored delusion – one’s image in a mirror is not oneself
• Intermetamorphosis – someone or an object exchanges identities
• Clonal pluralization – that other identical copies of the person exist
• Delusional companions – certain objects are actually living beings
• Doppelganger or Christodoulou syndrome – that there is a double of oneself

                                       * These can present in a variety of different psychotic disorders:
                                           e.g., schizophrenia, bipolar, psychotic depression, etc.

     Proper diagnosis depends on a thorough evaluation. Following the history, physical examination, and mental status assessments, laboratory studies are reviewed that pertain to the individualized case presentation. For example, brain imaging is ordered when new or changed mental status alterations are observed.

     Treatment is directed to the specific primary pathology. Symptomatic therapies are utilized, but remain secondary to the etiology-focused treatments and can co-exist if behaviorally indicated. Psychotherapeutic strategies are beneficial for coping skills and understanding in patients or families suffering with misidentification disorders.