Dissociative identity disorder (DID) is a psychiatric diagnosis
and describes a condition in which a person displays multiple distinct identities (known as alters or parts),
each with its own pattern of perceiving and interacting with the environment.
In the International
Statistical Classification of Diseases and Related Health Problems the name
for this diagnosis is multiple personality disorder. In both systems of
terminology, the diagnosis requires that at least two personalities (one may be
the host) routinely take control of the individual's behavior with an
associated memory loss that goes beyond normal forgetfulness; in
addition, symptoms cannot be the temporary effects of drug
use or a general medical condition. DID is less common than other dissociative disorders, occurring in
approximately 1% of dissociative cases, and is often comorbid
with other disorders.
There is a great deal of controversy
surrounding the topic of DID. The validity of DID as a medical diagnosis has
been questioned, and some researchers have suggested that DID may exist
primarily as an iatrogenic adverse effect of therapy. DID is diagnosed
significantly more frequently in North America than in the rest of the world.
Signs
and symptoms
Individuals diagnosed with DID
demonstrate a variety of symptoms with wide fluctuations across time;
functioning can vary from severe impairment in daily functioning to normal or
high abilities. Symptoms can include:
- Disruption of identity characterized by two
or more distinct personality states
- Multiple mannerisms, attitudes and beliefs
- Pseudoseizures or other conversion symptoms
- Somatic symptoms that vary across identities
- Distortion or loss of subjective time (a long
time)
- Current memory
loss of everyday events
- Depersonalization
- Derealization
- Depression
- Flashbacks of abuse/trauma
- Sudden anger without a justified cause
- Frequent panic/anxiety attacks
- Unexplainable phobias
Patients may experience a broad
array of other symptoms that may appear to resemble epilepsy, schizophrenia,
anxiety
disorders, mood disorders, post traumatic stress disorder, personality disorders, and eating
disorders.
Physiological
findings
Reviews of the literature have
discussed the findings of various psychophysiologic
investigations of DID. Many of the investigations include testing and
observation in a single person with different alters. Different alter states
have shown distinct physiological markers and some EEG studies have shown distinct differences
between alters in some subjects, while other subjects' patterns were consistent
across alters.
Neuroimaging studies of
individuals with dissociative disorders have found higher than normal levels of
memory encoding and a smaller than normal parietal
lobe.
Another study concluded that the
differences involved intensity of concentration, mood changes, degree of muscle
tension, and duration of recording, rather than some inherent difference
between the brains of people diagnosed with DID. Brain imaging studies have
corroborated the transitions of identity in some DID sufferers. A link between epilepsy and
DID has been postulated but this is disputed. Some brain
imaging studies have shown differing cerebral blood flow with different alters, and
distinct differences overall between subjects with DID and a healthy control
group.
A different imaging study showed
that findings of smaller hippocampal volumes in patients with a history of
exposure to traumatic stress and an accompanying
stress-related psychiatric disorder were also demonstrated in DID. This study
also found smaller amygdala volumes. Studies have demonstrated various changes
in visual parameters between alters. One twin study
showed heritable factors were present in DID.
Causes
This disorder is theoretically
linked with the interaction of overwhelming stress, traumatic antecedents, insufficient
childhood nurturing, and an innate ability to dissociate
memories or experiences from consciousness.
A high percentage of patients report child abuse.
People diagnosed with DID often report that they have experienced severe
physical and sexual abuse, especially during early to mid
childhood. Several psychiatric rating scales of DID sufferers suggested that
DID is strongly related to childhood trauma rather than to an underlying electrophysiological
dysfunction.
Others believe that the symptoms
of DID are created iatrogenically by therapists using certain treatment
techniques with suggestible patients, but this idea is not universally
accepted. Skeptics have suggested that a small subset of doctors are
responsible for the majority of diagnoses that a small number of therapists
were responsible for diagnosing the majority of individuals with DID.
Psychologist Nicholas Spanos and others skeptical of the
condition have suggested that in addition to iatrogenesis, DID may be the
result of role-playing rather than separate personalities, though
others disagree, pointing to a lack of incentive to manufacture or maintain separate
personalities and point to the claimed histories of abuse of these patients.
Development
theory
Severe sexual, physical, or
psychological trauma in childhood by a primary
caregiver has been proposed as an explanation for the development of DID.
In this theory, awareness, memories and feelings of a harmful action or event
caused by the caregiver is pushed into the subconscious
and dissociation becomes a coping mechanism for the individual during times of
stress. These memories and feelings are later experienced as a separate entity,
and if this happens multiple times, multiple alters are created.