Hallucinogen Persisting Perception Disorder (HPPD)
The definition of hallucinogen persisting perception disorder is shown in the following DSM-IV-TR Criteria.
It is not uncommon for a patient suffering from HPPD to consult multiple clinicians before a diagnosis is made. Because the symptoms are primarily perceptual, an HPPD subject may consult an ophthalmologist, neurologist, or psychologist before seeing a psychiatrist. Often patients come for help having made their own diagnoses using the DSM-IV or internet chat groups devoted to HPPD. Despite a patient’s certainty about their diagnosis, the clinician is obligated to rule out other sources of chronic organic hallucinosis, including other drug toxicities, strokes, CNS tumors, infections and head trauma. Magnetic resonance images of the brain are usually negative. Quantitative electroencephalography shows accelerated alpha and visual evoked potentials, especially in the posterior cerebrum.
Treatment at the present time is palliative. Benzodi-azepines, olanzepine, sertraline, naltrexone and clonidine have anecdotally been reported to help in selected cases. Risperidone has been reported to exacerbate HPPD symptoms Marijuana can chronically induce an exacerbation of HPPD. Because HPPD is also exacerbated by CNS arousal, affect, stress and stimulants, these are to be reduced or avoided. HPPD is worse with one’s eyes closed, or when entering a dark environment. Thus, sun-glasses, which serve to reduce the difference between outdoor and indoor luminance, may reduce HPPD symptoms when the patient enters an interior space.