Fugue-Like State and Psychosis in the Context of Chronic Cannabis Use

Occurring in 0.2%–7.2% of the general population, dissociative amnesia is one of three disorders listed in the DSM-5 under dissociative disorders (1). The disorder refers to a heterogeneous collection of psychological presentations, distinctive in the dimensions of content and timing (2). It is characterized by an inability to recall autobiographical information that may occur after an inciting traumatic event (3). The amnesia can be complete (generalized amnesia) or limited to a life event (localized amnesia). It is usually retrograde with an identifiable onset and termination. Dissociative amnesia involving purposeful travel or arbitrary wandering is termed dissociative fugue, a DSM-5 specifier that occurs in approximately 0.2% of the general population (1). Although the ICD-10 lists a dissociative fugue as a unique diagnosis, clinical and neuroimaging research findings support its new designation in the DSM-5 (4).

Retrospective and prospective studies tend to support a pathopsychological model implicating antecedent psychological stressors (5). It is commonly diagnosed in survivors of child abuse, sexual abuse, natural disasters, and war. A time lag may exist between the inciting trauma and the dissociative amnesia. Functional neuroimaging studies, which compared patients during amnesic episodes to age-matched healthy controls, have demonstrated hypometabolism in the right inferolateral prefrontal cortex in patients, implicating this region in the neural basis of dissociative amnesia (6). Dissociative amnesia usually remits spontaneously after removal from the traumatic situation. Hospitalization is required for patients who pose a danger to themselves or others and also offers separation from the stressful situation. Psychotherapy is the cornerstone of management for persistent cases. Hypnosis or drug-facilitated interviews may be helpful to recover lost memories and to manage the impact of resurfaced ones (2).

Case

“Mr. A” is a 51-year old Caucasian male brought in by police after being found sleeping outside a 7-Eleven 200 miles from his home in a neighboring state. According to initial police statements, the patient was unable to recall his name, home address, or the date. Throughout the interview, the patient was tearful, hostile, delusional, and tangential, often forgetting the initial question. The patient endorsed recent auditory hallucinations but refused to provide details. He denied visual hallucinations.

The patient had a history of aggravated sexual assault on a minor for which he served 20 years in prison. During his time in prison, he reported having experienced auditory hallucinations and was treated with risperidone. He refused to go into further detail about his time in prison but did endorse increased stress and the onset of numerous gaps in his memory. He explained that he lives with his ex-wife and works at a local car wash. He refused to discuss his childhood or family life, including any emotional, physical, or sexual abuse. The patient endorsed daily cannabis use since 15 years old.

Upon arrival, his dress and personal hygiene were poor. His eye contact and motor activity were normal. His behavior was threatening and restless. When attempting to complete a Mini Mental State Examination, the patient was unfocused, easily distracted, and uncooperative, refusing to answer several questions. He was disoriented to name, date, location, and situation. His physical examination was insignificant, and he was found to be in good physical health. Laboratory results were significant for an AST of 53 IU/L and ALT of 59 IU/L. His serum alcohol level was negative. His urine drug screen was positive for cannabis but did not detect other substances. An initial diagnosis of other psychotic disorders was made based on the presence of auditory hallucinations of unknown duration based on DSM-5 criteria. Additionally, the patient was diagnosed with cannabinoid use disorder based on patient history and a positive urine drug screen.

Once admitted to the unit, the patient was started on olanzapine (10 mg p.o. daily) for psychosis. Later that day, he had an episode of acute psychosis requiring chemical restraints, including haloperidol (10 mg via intramuscular injection once), diphenhydramine (50 mg via intramuscular once), and lorazepam (1 mg via intramuscular once).

The following day, the patient was tearful as he revealed details of an emotionally distressing altercation with a work associate that resulted in his manager threatening to fire him. He recalled waking up days later and “needed to do something important,” which led to his cross-state trip. Over the subsequent days, the patient slowly began to regain pieces of his amnesic episode. He was able to recall driving a distance, abandoning his car once it broke down, and hitching a ride from “evil individuals.”

Olanzapine was changed to an oral disintegrating form at 10 mg p.o. q.h.s. Over the following 3 days, the patient's mood and cognition improved, as did his acute psychosis. He attended several therapy sessions aimed at developing coping skills. He continued to refuse to discuss his past auditory hallucinations in detail or his time in prison and was never able to regain complete memory of the events during his fugue-like state. The patient met his treatment goals and was discharged in stable condition.

Discussion

The presence of a fugue-like state in the context of psychosis and cannabis use is rarely discussed in recent literature. A differential diagnosis of dissociative amnesia with dissociative fugue must be considered despite cannabis use and as an explanation for what were originally considered fugue-like symptoms. The patient in the above case was found far from his hometown, initially unable to recall important autobiographical information, which caused significant distress and impairment, resulting in his mental health detainment. It has been demonstrated that cannabis along with 3,4-methylenedioxy-methamphetamine, cocaine, and other substances can cause and increase dissociative symptoms (7) and that cannabis and other substances can elicit psychotic symptoms (8). The literature has discussed a possible link between dissociative symptoms and psychotic symptoms in patients with a history of sexual child abuse (9) or certain medications (10). A 2013 case report described a 43-year-old male who entered a fugue-like state during an acute psychotic episode after initiating tacrolimus (10). After treating the acute psychotic episode and discontinuing tacrolimus, his condition improved.

In our case, the patient's history of regular cannabis use precludes a DSM-5 diagnosis of dissociative amnesia due to criterion C of dissociative amnesia; however, his dissociative symptoms do meet criteria for unspecified dissociative disorder. In addition, due to his cannabis use and psychotic symptoms, he meets all criteria in the DSM-5 for substance-induced psychotic disorder. While cannabis use has been shown to independently cause either psychosis or dissociation in patients (7, 8), we propose further exploration into the role of cannabis, as it may highlight common neurobiological mechanisms underlying both dissociative and psychotic symptoms. Understanding the mechanism by which cannabis produces these symptoms might enhance our current understanding of both and aid in the management of these patients.

Key Points/Clinical Pearls