Text Size :

Causes of Dissociative Disorders

Trauma and Dissociation

On describing her experiences of being abducted and repeatedly raped, one victim explained, "it's like a story that happened to someone else." It seems that when the mind is confronted with horribly disturbing and traumatic experiences, one way of coping with these events is to separate the awareness of them from the rest of one's consciousness.

This is the currently accepted theory of what causes major dissociative symptoms and disorders. Splitting-off these awarenesses from one's consciousness can take many forms, such as dissociating the memories completely, or censoring the feelings and realness that would normally be attached those memories. Dissociation also allows people to cope with traumatic events in real-time, by splitting-off their awareness of pain or fear, or causing them to feel removed from the situation.

Research has demonstrated clear links between highly traumatic experiences and dissociative symptoms and disorders [ref]. It is believed that the more extensive and repetitive the traumatic events are, and the earlier in life that they occur, the more profound and pervasive will be the ensuing dissociative problems. Dissociative Identity Disorder (Multiple Personality Disorder), which is considered to be the most severe form of Dissociative Disorder, has been likened to Complex PTSD [ref]

Personality Traits and Proneness to Dissociation

However, probably not all people who experience dissociative experiences have necessarily endured highly traumatic experiences, and people probably differ in the amount of trauma that would be required to make them dissociate. It has been suggested that certain people may be more prone than others to having dissociative experiences, and that these tendencies may be related to being easily hypnotized and also to having an ability to become highly absorbed in one's experiences [ref].

Hypnosis involves having one's thoughts, perceptions, sensations and behaviors strongly influenced and altered by suggestion, that is, by someone else's instructions. The hypnotized person seems to allow their mental functions to be controlled by another person rather than by their own will and intentions. People differ in the extent to which they can be hypnotized.

Absorption is a personality trait that involves the ability to "lose oneself in an experience," that is, to become completely absorbed in an experience to the point where one begins to lose an awareness of the self, or where the boundaries between the self and the outer world become blurred [ref]. Many people can experience this on certain occasions, such as watching a gripping movie, or having an intense mystical or religious experience. Trance states, or meditation, are other examples of situations where the boundaries between the self and the world can become blurred. Yet some individuals with strong absorption traits seem to have a capacity to do this under many circumstances, and can often lose themselves in their vivid imaginations.

There is some evidence that people with Dissociative Disorders tend to be highly hypnotizable; that easily hypnotizable people have strong absorption traits; and that having prominent absorption traits is associated with a tendency for experiencing dissociative symptoms [ref]. In other words, these features may all be related in some way, and may represent a constellation of mental functions that form a normal and important part of the human mind.

One possibility is that these mental functions exist in order help people bond and coalesce with each other into social groups by allowing individuals to lose a bit of their self-awareness and to feel merged with the collective. For example, trance states can be induced by intense communal rituals, and groups may also use various drugs and substances to bring-on altered states of consciousness among the members. Adolescents tend to have dissociative experiences more often than adults [ref], and also tend to experiment frequently with psychoactive substances, which may be in keeping with this stage of life when group-building is important. Social bonding and action can be an effective way for people to manage stressful situations, and this may explain part of the association between traumatic experiences and dissociative symptoms. The use of physical pain in the rituals of certain groups, especially initiation rites, may also serve as a way to induce dissociative states and thus foster group bonding and cohesion.

The Biology of Dissociation

If dissociative symptoms reflect a normal and common feature of human psychology, then one would expect that they would have some genetic underpinnings. There is some evidence that genetic factors do account for about half of the risk of having dissociative experiences [ref, ref].

The hippocampus is the part of the brain that is responsible for encoding and retrieving memories, and also for building mental maps of time and space. There is some evidence that altered hippocampal activity plays a key role in the experience of dissociation [ref]. Classic studies revealed that patients undergoing neurosurgery while still conscious would have powerful dissociative symptoms, including depersonalization and derealization, when their hippocampi were stimulated [ref]; this phenomenon may be a result of a disruption of a person's sense of themselves in time and space. It is also well known that under stressful situations, stress hormones like cortisol can alter the functioning of the hippocampus and impair memory encoding and retrieval, which may account for dissociative amnesia [ref].

Certain drugs, like Ketamine, PCP and hallucinogens are known to cause dissociative symptoms. The precise ways in which these substances have their effects is not fully known, but Ketamine and PCP seem to modulate glutamate receptors in the brain, while some hallucinogens may affect the serotonin system.


prev | next


Course & Prevalence