出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/07/26 19:15:15」(JST)
Alexithymia /ˌeɪlɛksəˈθaɪmiə/ is a personality construct characterized by the sub-clinical inability to identify and describe emotions in the self.[1] The core characteristics of alexithymia are marked dysfunction in emotional awareness, social attachment, and interpersonal relating.[2] Furthermore, individuals suffering from alexithymia also have difficulty in distinguishing and appreciating the emotions of others, which is thought to lead to unempathic and ineffective emotional responding.[2] Alexithymia is prevalent in approximately 10% of the general population and is known to be comorbid with a number of psychiatric conditions.[3]
The term "alexithymia" was coined by psychotherapist Peter Sifneos in 1973.[4][5] According to the OED, the word comes from the Greek words λέξις (lexis, "speech") and θυμός (thumos, "soul, as the seat of emotion, feeling, and thought") modified by an alpha privative, literally meaning "no words for emotions".
Alexithymia is considered to be a personality trait that places individuals at risk for other medical and psychiatric disorders while reducing the likelihood that these individuals will respond to conventional treatments for the other conditions.[6] Alexithymia is not classified as a mental disorder in the DSM-IV. It is a dimensional personality trait that varies in severity from person to person. A person's alexithymia score can be measured with questionnaires such as the Toronto Alexithymia Scale (TAS-20), the Bermond-Vorst Alexithymia Questionnaire (BVAQ),[7] the Online Alexithymia Questionnaire (OAQ-G2)[8] or the Observer Alexithymia Scale (OAS).[6]
Alexithymia is defined by:[9]
In studies of the general population the degree of alexithymia was found to be influenced by age, but not by gender; the rates of alexithymia in healthy controls have been found at: 8.3% (2 of 24 persons); 4.7% (2 of 43); 8.9% (16 of 179); and 7% (4 of 56). Thus, several studies have reported that the prevalence rate of alexithymia is less than 10%.[10] A less common finding suggests that there may be a higher prevalence of alexithymia amongst males than females, which may be accounted for by difficulties some males have with "describing feelings", but not by difficulties in "identifying feelings" in which males and females show similar abilities.[11]
Psychologist R. Michael Bagby and psychiatrist Graeme J. Taylor have argued that the alexithymia construct is strongly related (negatively) to the concepts of psychological mindedness[12] and emotional intelligence[13][14] and there is "strong empirical support for alexithymia being a stable personality trait rather than just a consequence of psychological distress".[15] Other opinions differ and can show evidence that it may be state-dependent.[16]
Bagby and Taylor also suggest that there may be two kinds of alexithymia, "primary alexithymia" which is an enduring psychological trait that does not alter over time, and "secondary alexithymia" which is state-dependent and disappears after the evoking stressful situation has changed. These two manifestations of alexithymia are otherwise called "trait" or "state" alexithymia.[15]
Typical deficiencies may include problems identifying, describing, and working with one's own feelings, often marked by a lack of understanding of the feelings of others; difficulty distinguishing between feelings and the bodily sensations of emotional arousal;[4] confusion of physical sensations often associated with emotions; few dreams or fantasies due to restricted imagination; and concrete, realistic, logical thinking, often to the exclusion of emotional responses to problems. Those who have alexithymia also report very logical and realistic dreams, such as going to the store or eating a meal.[17] Clinical experience suggests it is the structural features of dreams more than the ability to recall them that best characterizes alexithymia.[4]
Some alexithymic individuals may appear to contradict the above mentioned characteristics because they can experience chronic dysphoria or manifest outbursts of crying or rage.[18][19][20] However, questioning usually reveals that they are quite incapable of describing their feelings or appear confused by questions inquiring about specifics of feelings.[9]
According to Henry Krystal, individuals suffering from alexithymia think in an operative way and may appear to be superadjusted to reality. 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.[21][22] In general, these individuals lack imagination, intuition, empathy, and drive-fulfillment fantasy, especially in relation to objects. Instead, they seem oriented toward things and even treat themselves as robots. These problems seriously limit their responsiveness to psychoanalytic psychotherapy; psychosomatic illness or substance abuse is frequently exacerbated should these individuals enter psychotherapy.[9]
A common misconception about alexithymia is that affected individuals are totally unable to express emotions verbally and that they may even fail to acknowledge that they experience emotions. Even before coining the term, Sifneos (1967) noted patients often mentioned things like anxiety or depression. The distinguishing factor was their inability to elaborate beyond a few limited adjectives such as "happy" or "unhappy" when describing these feelings.[23] The core issue is that alexithymics have poorly differentiated emotions limiting their ability to distinguish and describe them to others.[4] 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.[24]
It is unclear what causes alexithymia, though several theories have been proposed. There is evidence both for a genetic basis, meaning some people are predisposed to develop alexithymia, as well as for environmental causes.
Early studies showed evidence that there may be an interhemispheric transfer deficit among alexithymics; that is, the emotional information from the right hemisphere 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.[25] A neuropsychological study in 1997 indicated that alexithymia may be due to a disturbance to the right hemisphere of the brain, which is largely responsible for processing emotions.[26] In addition, another neuropsychological model suggests that alexithymia may be related to a dysfunction of the anterior cingulate cortex.[27] These studies have some shortcomings, however, and the empirical evidence about the causes of alexithymia remains inconclusive.[28] French psychoanalyst Joyce McDougall objected to the strong focus by clinicians on neurophysiological at the expense of psychological explanations for the genesis and operation of alexithymia, and introduced the alternative term "disaffectation" to stand for psychogenic alexithymia.[29] For McDougall, the disaffected individual had at some point "experienced overwhelming emotion that threatened to attack their sense of integrity and identity", to which they applied psychological defenses to pulverize and eject all emotional representations from consciousness.[30] A similar line of interpretation has been taken up using the methods of phenomenology.[31]
McDougall has also noted that all infants are born unable to identify, organize, and speak about their emotional experiences (the word infans is from the Latin "not speaking"), and are "by reason of their immaturity inevitably alexithymic".[32] Based on this fact McDougall proposed in 1985 that the alexithymic part of an adult personality could be "an extremely arrested and infantile psychic structure".[32] The first language of an infant is nonverbal facial expressions. The parent's emotional state is important for determining how any child might develop. Neglect or indifference to varying changes in a child's facial expressions without proper feedback can promote an invalidation of the facial expressions manifested by the child. The parent's ability to reflect self-awareness to the child is another important factor. If the adult is incapable of recognizing and distinguishing emotional expressions in the child, it can influence the child's capacity to understand emotional expressions.[4]
Although environmental, neurological, and genetic factors are each involved, the role of genetic and environmental factors for developing alexithymia is still unclear.[33] The results from a large population-based sample of Danish twins suggested that genetic factors contributed noticeably to the development of alexithymia. While the results suggested a moderate influence of environmental factors that were shared between twin pairs, the authors found that non-shared environmental influences had the greatest impact on psychological traits, which was consist with earlier findings.[further explanation needed][33] One hypothesized environmental cause is head injury; persons suffering a traumatic brain injury are six times more likely to exhibit alexithymia.[34]
In 2011, the International Journal of Men's Health published a study which found that circumcised men were approximately 60% more likely to score highly on a standardized alexithymia test. The authors hypothesized that the trauma of the procedure may contribute to personality disorders later in life. The abstract reads:
"Three hundred self-selected men were administered the Toronto Twenty-Item Alexithymia Scale checklist and a personal history questionnaire. The circumcised men had age-adjusted alexithymia scores 19.9 percent higher than the intact men; were 1.57 times more likely to have high alexithymia scores; were 2.30 times less likely to have low alexithymia scores; had higher prevalence of two of the three alex-ithymia factors (difficulty identifying feelings and difficulty describing feelings); and were 4.53 times more likely to use an erectile dysfunction drug. Alexithymia in this population of adult men is statistically significant for having experienced circumcision trauma and for erectile dysfunction drug use." [2]
Alexithymia creates interpersonal problems because these individuals tend to avoid emotionally close relationships, or if they do form relationships with others they usually position themselves as either dependent, dominant, or impersonal, "such that the relationship remains superficial".[35] Inadequate "differentiation" between self and others by alexithymic individuals has also been observed.[36]
In a study, a large group of alexithymic individuals completed the 64-item Inventory of Interpersonal Problems (IIP-64) which found that "two interpersonal problems are significantly and stably related to alexithymia: cold/distant and non-assertive social functioning. All other IIP-64 subscales were not significantly related to alexithymia."[35]
Chaotic interpersonal relations have also been observed by Sifneos.[37] Due to the inherent difficulties identifying and describing emotional states in self and others, alexithymia also negatively affects relationship satisfaction between couples.[38]
In a 2008 study[39] alexithymia was found to be correlated with impaired understanding and demonstration of relational affection, and that this impairment contributes to poorer mental health, poorer relational well-being, and lowered relationship quality.[39] Individuals high on the alexithymia spectrum also report less distress at seeing others in pain and behave less altruistically toward others.[2]
Some individuals working for organizations in which control of emotions is the norm might show alexithymic-like behavior but not be alexithymic. However, over time the lack of self-expressions can become routine and they may find it harder to identify with others.[40]
Alexithymia frequently co-occurs with other disorders. Research indicates that alexithymia overlaps with autism spectrum disorders.[8][41] In a 2004 study using the TAS-20, 85% of the adults with ASD fell into the impaired category; almost half of the whole group fell into the severely impaired category. Among the normal adult control, only 17% was impaired; none of them severely.[41][42] Fitzgerald & Bellgrove pointed out that, "Like alexithymia, Asperger's syndrome is also characterised by core disturbances in speech and language and social relationships".[43] Hill & Berthoz agreed with Fitzgerald & Bellgrove (2006) and in response stated that "there is some form of overlap between alexithymia and ASDs". They also pointed to studies that revealed impaired theory of mind skill in alexithymia, neuroanatomical evidence pointing to a shared etiology and similar social skills deficits.[44] The exact nature of the overlap is uncertain. Alexithymic traits in AS may be linked to clinical depression or anxiety;[42] the mediating factors are unknown and it is possible that alexithymia predisposes to anxiety.[45]
There are many more psychiatric disorders that overlap with alexithymia. One study found that 41% of Vietnam War veterans with post-traumatic stress disorder were alexithymic.[46] Other single study prevalence findings are 63% in anorexia nervosa,[47] 56% in bulimia,[47] 45%[16] to 50%[48] in major depressive disorder, 34% in panic disorder,[49] 28% of social phobics,[49] and 50% in substance abusers.[50] Alexithymia also occurs more frequently in individuals with acquired or traumatic brain injury.[51][52][53]
Alexithymia is correlated with certain personality disorders,[54] substance use disorders,[55][56] some anxiety disorders,[57] and sexual disorders,[58] as well as certain physical illnesses, such as hypertension,[59] inflammatory bowel disease,[60] and functional dyspepsia.[61] Alexithymia is further linked with disorders such as migraine headaches, lower back pain, irritable bowel syndrome, asthma, nausea, allergies, and fibromyalgia.[62]
An inability to modulate emotions is a possibility in explaining why some alexithymics 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.[63] The failure to regulate emotions cognitively might result in prolonged elevations of the autonomic nervous system (ANS) and neuroendocrine systems which can lead to somatic diseases.[62] Alexithymics also show a limited ability to experience positive emotions leading Krystal (1988) and Sifneos (1987) to describe many of these individuals as anhedonic.[5]
|
||||||||||||||||||||||||||||||||||||
| リンク元 | 「失感情症」「alexithymia」 |
-alexithymia
-アレキシサイミア