Synthetic Cannabis Substances (SPS) Use and Hallucinogen Persisting Perception Disorder (HPPD): Two Case Reports

Area of Science:

• Neuroscience
• Psychiatry
• Pharmacology

Background:

• Hallucinogen Persistent Perceptual Disorder (HPPD) is defined by recurring perceptual disturbances post-hallucinogen use.
• Synthetic Cannabis Substances (SCS) are increasingly prevalent, with less understood psychotomimetic effects.

Observation:

• Two patients with prior cannabis and tobacco dependence developed HPPD after using SCS.
• Visual disturbances, including those with stationary and moving objects, were reported during SCS intoxication.
• Patients experienced panic attacks during SCS use, leading to abrupt cessation.

Findings:

• Despite SCS cessation, patients continued to experience HPPD symptoms, notably accompanied by significant anxiety.
• Clonazepam treatment led to marked improvement in HPPD symptoms and associated anxiety.
• A residual focal visual disturbance, without significant anxiety, persisted post-treatment.

Implications:

• These are the first reported cases of HPPD following synthetic cannabis substance use.
• Clinicians should be aware of the potential for HPPD as a side effect of SCS.
• Increased vigilance is necessary due to the rising use of SCS and associated adverse perceptual effects.