[11][12][13][6] The term alexithymia was introduced by psychotherapists John Case Nemiah and Peter Sifneos in 1970 to describe a particular psychological phenomenon.
The word is formed by combining the alpha privative prefix ἀ- (a-, meaning 'not') with λέξις (léxis, referring to 'words') and θῡμός (thȳmós, denoting 'disposition,' 'feeling,' or 'rage').
[17] This label reflects the difficulty experienced by individuals with this condition in recognizing, expressing, and articulating their emotional experiences.
[21] Cognitive behavioral and psychoanalytic theorists have proposed conceptualizations, including lists of characteristic signs and symptoms.
Studies that have directly compared these measures have consistently found the PAQ to be the best performing psychometrically, with strong evidence for it providing a comprehensive and reliable alexithymia profile.
[60][61][62][63][64] Several observer-rated or interview-based measures of alexithymia also exist,[65][66] but so far these have been rarely used in research or clinical settings due to long administration times.
[15] Some alexithymic individuals may appear to contradict the above-mentioned characteristics because they can experience chronic dysphoria or manifest outbursts of crying or rage.
In psychotherapy, however, a cognitive disturbance becomes apparent as patients tend to recount trivial, chronologically ordered actions, reactions, and events of daily life with monotonous detail.
[76] The core issue is that people with alexithymia have poorly differentiated emotions, limiting their ability to distinguish and describe them to others.
[15] This contributes to the sense of emotional detachment from themselves and difficulty connecting with others, making alexithymia negatively associated with life satisfaction even when depression and other confounding factors are controlled for.
[80][81] Fitzgerald & Bellgrove pointed out that, "Like alexithymia, Asperger's syndrome is also characterised by core disturbances in speech and language and social relationships".
[82] Note that, Asperger's syndrome has been merged with other conditions into autism spectrum disorder (ASD) and is no longer a diagnosis in the WHO's ICD-11 or the APA's DSM-5-TR.
[83][84][85] Hill & Berthoz agreed with Fitzgerald & Bellgrove (2006) and in response stated that "there is some form of overlap between alexithymia and ASDs".
[90] Higher levels of alexithymia among mothers with interpersonal violence-related PTSD were found in one study to have proportionally less caregiving sensitivity.
[91] This latter study suggested that when treating adult PTSD patients who are parents, alexithymia should be assessed and addressed also with attention to the parent-child relationship and the child's social-emotional development.
[109] Alexithymia is further linked with disorders such as migraine headaches, lower back pain, irritable bowel syndrome, asthma, nausea, allergies and fibromyalgia.
[111][112] An inability to modulate emotions is a possibility in explaining why some people with alexithymia are prone to discharge tension arising from unpleasant emotional states through impulsive acts or compulsive behaviors such as binge eating, substance abuse, perverse sexual behavior or anorexia nervosa.
[110] People with alexithymia also show a limited ability to experience positive emotions leading Krystal[114] and Sifneos (1987) to describe many of these individuals as anhedonic.
Early studies showed evidence that there may be an interhemispheric transfer deficit among people with alexithymia; that is, the emotional information from the right hemisphere of the brain is not being properly transferred to the language regions in the left hemisphere, as can be caused by a decreased corpus callosum, often present in psychiatric patients who have suffered severe childhood abuse.
A study recruiting a test population of Japanese males found higher scores on the Toronto Alexithymia Scale among those with the 5-HTTLPR homozygous long (L) allele.
[127] These links are tentative, and further research will be needed to clarify how these genes relate to the neurological anomalies found in the brains of people with alexithymia.
[128] A single large scale Danish study suggested that genetic factors contributed noticeably to the development of alexithymia.
[136] Due to the inherent difficulties identifying and describing emotional states in self and others, alexithymia also negatively affects relationship satisfaction between couples.
[5][23] In 2018, Löf, Clinton, Kaldo, and Rydén found that mentalisation-based treatment is also an effective method for treating alexithymia.
Mentalisation is the ability to understand the mental state of oneself or others that underlies overt behavior, and mentalisation-based treatment helps patients separate their own thoughts and feelings from those around them.