Hallucinogen persisting perception disorder (HPPD) is a rare psychiatric diagnosis encompassing a range of perceptual disturbances caused by the lingering effects of hallucinogens. There are two major subtypes of the disorder: HPPD I and II. HPPD II is considered a more severe form that is generally longer-term, distressing, and requiring more intense treatment. In the limited available literature, many of the affected patients have multiple psychiatric comorbidities. The following case describes a 24-year-old college student, WA, who was diagnosed with HPPD II along with comorbid bipolar I disorder and generalized anxiety disorder. WA presented with an escalation of manic symptoms, psychosis, and two lysergic acid diethylamide (LSD) uses prior to hospitalization. He was treated with olanzapine, leading to mood stabilization and remission of psychosis. Post treatment, WA continued to experience perceptual disturbances and "visual snow." Medications clonidine and clonazepam were trialed for HPPD. While symptoms fluctuated in severity, they never fully resolved. Despite this, WA achieved acceptance of his symptoms, mood stability, and a functional recovery. WA's case is an example of the clinical complexity in accurate diagnosis and treatment of HPPD, including the distinction of the symptoms from psychosis. As LSD-assisted therapies continue to be investigated for conditions such as anxiety and depression, recognition and management of persistent adverse effects such as HPPD are becoming increasingly important in both psychiatric and general medical practice. This case demonstrates the limited effectiveness and lack of knowledge on HPPD treatments as well as the need for longitudinal assessments in management.
