Lethologica is a psychological disorder that inhibits an individual's ability to articulate his or her thoughts by temporarily forgetting key words, phrases or names in conversation.


Lethologica was first identified as a serious, debilitating disorder by Swiss psychiatrist Carl Jung in 1913 in his Wandlungen und Symbole der Libido (The Psychology of the Unconscious). Detailed studies of the disorder were first carried out by American psychiatrists in the 1950s. Current research identifies the ailment as extremely prevalent but also highly variable in its severity of manifestation. According to the American Psychiatric Association, "9 out of 10 Westerners will suffer some form of Lethologica during their lifetimes."

The word lethologica is derived from the Greek language terms for forgetfulness (letho) and word (logos). Letho originates from Greek mythology; the Lethe (or River of Oblivion) was one of the rivers that flowed through the realm of Hades, from which the shades of the dead were forced to drink in order to forget their past lives on earth.


Lethologica's severity amongst sufferers is dependent upon a variety of factors including stress, physical fitness, social interaction and base memory capacity. As such it can be classified as a lifestyle disease which is also affected by individual personality traits. These factors have been shown to affect the temporal lobe which in turn causes the sporadic functioning of episodic and semantic memory capacities. Lethologica afflicts in a manner almost opposite to that of other memory disorders such as Alzheimer's Disease or other forms of dementia in that strenuous mental exercise can precipitate an onset of memory loss.

Clinical findings

The key finding is forgetfulness of words. However, patients suffering from lethologica often portray a wide range of clinical features. The Swiss neurologist and psychiatrist, Dr Constantin von Monakow, described a triad of findings which also aid in the diagnosis, of which 2 of 3 must be present in order to make the diagnosis:

  • Disordered pharyngeal phase of swallowing
  • Increased tone in upper limb muscle groups, exacerbated when attempting to remember specific words
  • Recurrent inappropriate gestures while attempting to remember particular words, e.g. lip smacking

Recent studies demonstrating a close relationship between lethologica and disordered pharyngeal phase of swallowing have made some neurologists postulate that the disease may well affect the X and/or XII cranial nerves, in addition to the temporal lobe.


Unfortunately no effective treatments for the disorder exist. Current research is focussing on the use of electroconvulsive therapy (ECT) as a potential treatment of this pervasive disorder. Scientists and clinicians are also closely investigating the related non-pathological condition, tip of the tongue, to aid in further research into this condition.

See also

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