Possession Trance, Epilepsy, and Primary Psychosis: the Challenges in Diagnosis and Management

To the Editor: ‘Trance’ derives from the Latin words transitus (a passage) and transpire (to pass over). The most common clinical features of a trance state are amnesia, emotional disturbances and loss of identity.¹ It is clinically challenging to differentiate behavior changes resulting from epilepsy, functional psychosis, and culturally sanctioned ‘possession’ states. These two cases illustrate this challenge.

Case Report #1

X is a 56-year-old Chinese woman with no significant medical or psychiatric history. She came from a deeply religious background and prayed daily at the altar at her home. She presented with episodes of bizarre behavior—erratic movements of all four limbs, mumbling to herself, unresponsiveness, and staring blankly. She had been experiencing this twice a year for two decades. She believed that her body was taken over by a Taoist God and would speak and gesture as she was asked to. She retained no memory of these events. She was admitted to the intensive care unit following a similar episode to rule out status epilepticus. Extensive physical examination and investigations, including brain imaging and electroencephalograms, were however normal.

Case Report #2

Y is a 51-year-old Chinese man with a background medical history of epilepsy diagnosed at age 20 with multiple admissions for breakthrough seizures because of partial adherence to his antiepileptic drugs. His seizures were usually brought on by reading and looking at television or computer screens. He sustained a head injury following a generalized tonic-clonic seizure 2 years ago, resulting in increased seizure frequency and duration despite medication adherence. Y typically had a period of postictal confusion lasting minutes to several hours when he was disoriented.

He also experienced distinct episodes where he would take on the persona of a Taoist God—speak, gesture, chant, and perform rituals; heard the voices and saw images of other Gods. He retained no memory of these episodes. These episodes had begun 6 years ago since he became involved with temple rituals as a means to help control his seizures. Initially, it would occur in a religious context, but recently, they occurred spontaneously and more frequently. Y did not always have control over the onset of these episodes. There was no clear pattern between the frequency of seizures and trance states. Recent MRI of the brain showed gliosis in the left frontal and temporal lobes. An electroencephalogram done during a trance state was normal. There were concerns that his hallucinatory experiences were part of a psychotic illness.

Discussion

Dissociative possession states —illness or cultural?

Possession states manifest in various different ways depending on the local culture and beliefs. Bourguignon et al² found that 90% of a worldwide sample of 488 societies displayed trance and/or possession— it appears that this phenomenon, although not very well documented in the literature, is in fact common.

Singapore is a multiracial country. According to the 2012 national population census,³ Chinese form the majority at 74%, followed by the Malays with 13%, and the Indians with 9.2%. All three of these dominant ethnic groups have deeply rooted spiritual beliefs. The Chinese believe that there are two types of spirits and ghosts—one that looks after the welfare of the living and those that do harm if not appeased. Spirit mediums are revered and thought of as gifted individuals who have the special ability to communicate with spiritual beings. The Malays too encounter trance states—main petri (Kelantanese healing ceremony), ilmu pencak silat (malay martial arts), and kuda kepang (horse possessions) are some examples. Thaipussam is a major religious festival for the Hindus that involve fire-walking and carrying kavadi. Worshippers are usually in a trance state.

In a local study of possession-trance states,⁴ what was notable was that there were significant similarities in phenomenology across the different races despite markedly different cultural backgrounds. The study also noted that stiffening of limbs and jerking occurred most commonly and possession-trance states appeared to be precipitated by fear/anxiety.

At present, according to the DSM-IV TR,⁵ dissociative trance disorder comes under Dissociative Disorders Not Otherwise Specified. There are differences in phenomenology between a trance and a possession state. The latter involves the replacement of personal identity with a new identity, which is attributed to a ‘spirit, power, deity, or another person.’ Possession states are commonly more elaborate.

In regions of the world where brief dissociative states in culturally and religiously sanctioned contexts occur frequently in the absence of other psychiatric illnesses, it gives rise to diagnostic conflict. When do we call it a mental illness? Griffith and Ruiz⁶ suggested that possession becomes abnormal when: 1) it lasts too long; 2) there is no perceivable stimulus or condition; and 3) it has a negative orientation.

Moving forward, DSM V has proposed that trance and possession trance be treated as separate entities and possession trance to be subsumed as a dissociative identity disorder (DID).⁷ The reasons for this move have been discussed—possession trance and trance states are phenomenologically different and should not be lumped together; possession trance states are phenomenologically similar to DID, and it is probably a cultural variant; emerging link between trauma and possession trance and because of its cultural bias it is currently being under-diagnosed and under-treated.⁷

Dissociative states and epilepsy

Dissociative disorders and epilepsy share many clinical features including amnesia, fugue, depersonalization, derealization, and identity change making it a diagnostic challenge. Studies of patients with epilepsy and dissociative states show that organic fugue states are also common. When postictal personality changes occur, they are usually time limited and not complex.

Dissociative symptoms can be misdiagnosed as epilepsy in the absence of an ictal EEG; conversely epilepsy can be misdiagnosed as a dissociative disorder if there is a normal non-ictal EEG. Patients with temporal lobe epilepsy may present with psychiatric symptoms and have nonspecific EEG changes. Even those patients with overt clinical manifestations of a seizure disorder may have a normal EEG. In patients with dissociative disorders, abnormal EEG’s are seen in 30%‒44%, and comorbid epilepsy is seen in 10%.⁸ This is higher than the general population, however, there is no definite etiological link making an increased awareness among neurologists essential.

A clearer diagnosis of epilepsy versus dissociation can be made using video-EEG monitoring, which should be normal in dissociative states not related to seizure activity. This is, however, labor intensive, expensive, and not without false positives/negatives.

Both cases had similar presenting features albeit somewhat more complex phenomenology in Y’s case echoing what is already known in the local literature. They both had deeply rooted religious beliefs predating the onset of dissociative states and rigorous investigations were negative. What enabled us to ascertaining diagnoses and care planning was a clear history that was taken with an understanding of culturally sanctioned behavior.

Conclusions

The distinction between an epileptic phenomenon, functional psychosis, and possession- trance state is not easy to make. Awareness of cultural nuances, careful history taking, strict adherence to diagnostic criteria, use of structured interviews, neurological investigations, and longitudinal follow-up facilitates accurate diagnosis and appropriate care.