What a Long, Strange Trip It’s Been: Trauma in Hallucinogen-persisting Perception Disorder

This session is not available for CE credit.

Abstract
Hallucinogen-persisting perception disorder (HPPD) refers to a condition in which an individual who has consumed a mind-altering substance continues to experience aberrant false sensory impressions long after the substance has left their body. Lingering effects typically occur sporadically and are often described as visual images. The most frequently reported impressions include visual snow, flashes of color, color intensification, trailing images from moving objects (tracers), after images, geometric figures, haloes, micropsia, and macropsia.

While it has been espoused that HPPD is relatively rare, some 4% of users of LSD-25 will develop the condition. Considering the recent resumed and growing popularity of hallucinogen use, it seems probable that HPPD will become more prevalent in the coming years, constituting a rising public health concern. At present, literature concerning the condition is relatively scant, and there is a dearth of published research on etiology that ventures outside the realm of biological reductionism. While conspicuously high psychiatric comorbidities have been established, until this point, no studies have thoroughly investigated the role of trauma and the function of dissociation in the development and maintenance of HPPD.

Importantly, there are two variants of the disorder. Individuals diagnosed with type I HPPD report to experience their symptomatology as fairly benign, short-lived, and characteristically deny having encountered any noteworthy distress during the hallucinogenic experience that ostensibly produced their lingering perceptual experiences. Other individuals (type II HPPD) often report to have experienced what are commonly termed “bad trips,” in which an altered state of consciousness encountered while under the effects of a hallucinogen, including false sensory impressions, accompanies a profoundly unpleasant affective experience, often described as terrifying or horrific. Individuals diagnosed with type II HPPD typically experience symptomatology for many months, if not years, or even decades, producing considerable distress and impaired functioning.

Contemporary etiological theories of HPPD, consistently residing in the realm of chemical imbalance models, will be described. These approaches have produced high quality research that has illuminated certain mechanisms putatively at play in the development of the disorder, but, because such research is geared toward identifying targets for pharmacological treatment, it is limited to a linked level of analysis. Current theories are seemingly divorced from any notion that lingering pathology observed in HPPD may be directly produced by affective experience, later cued by external stimuli, modulated by defensive processes, or remediated through psychotherapeutic means.

Results of a new study involving a sample of individuals experiencing type II HPPD will be discussed. Participants recruited from an online support forum, with members globally distributed, completed a series of measures, including the PTSD Checklist for DSM-5 (PCL-5), Dissociative Experience Scale-II (DES-II), the Adverse Childhood Experiences (ACEs) questionnaire, and an assessment of current HPPD symptoms. While the chief intentions of the presentation are to suggest a traumatogenic theory of the development of type II HPPD, and to describe the role of dissociative processes in maintaining the subsequent pathology, implications for psychotherapeutic treatment of the condition will also be discussed, as, heretofore, psychopharmacological interventions have been touted as the treatment of choice.