5-METHOXY-N,N-DIISOPROPYLTRYPTAMINE-INDUCED FLASHBACKS

To the Editor:

The drug 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT) has
hallucinogenic and mild euphoric properties, similar to
those of other tryptamine compounds (1).
Hallucinogen-persisting perception disorder is
characterized by the transient recurrence of perceptual
symptoms experienced while intoxicated with the
hallucinogen, often called "flashbacks." LSD-induced
flashbacks are well known. It is also reported that
hallucinogen-persisting perception disorder is induced
by cannabis and methamphetamine. However, to our
knowledge, there are no published reports of
5-MeO-DIPT-induced hallucinogen-persisting perception disorder.

Mr. A, a 35-year-old Japanese man without a previous psychiatric
history, was seen with perceptual disturbances. One month before his
evaluation, he had stopped using 5-MeO-DIPT because of a so-called bad
trip--anxiety, palpitations, auditory oversensitiveness, and visual
distortion--after six or seven times using between 15 mg and 30 mg of
5-MeO-DIPT over 5 months. He was bisexual and had used the drug to
enhance intercourse with a male partner. A few days before his
evaluation, after the announcement of his father's diagnosis of a
brain tumor, his 5-MeO-DIPT-induced phenomena of a "bad trip"
returned, although he had not taken 5-MeO-DIPT.

There was no evidence of CNS infection or organic brain disease.
Amphetamine was not detected in Mr. A's urine. He was not clinically
depressed. Schizophrenia-like symptoms, such as delusions or auditory
hallucinations, were not present. He was given oral risperidone, 1
mg/day. Within 3 days, his perceptual disturbances remarkably
decreased, and 7 days later, they had almost completely disappeared.
Given his clinical features and history of drug ingestion, we made a
diagnosis of hallucinogen-persisting perception disorder induced by
5-MeO-DIPT. Mr. A was discharged 1 month later. Although this
medication was maintained for 4 months and then terminated, he has had
no relapse.

The disturbances of serotonergic function may be a factor in
hallucinogen-persisting perception disorder, although the
pathophysiology remains unclear. Regarding the treatment of
LSD-induced flashbacks, the choice of medication is still
controversial. The use of various agents, including neuroleptics,
serotonin reuptake inhibitors (SSRIs), anticonvulsants, and
benzodiazepines, has met with limited success (2). Some researchers
report that risperidone, which is a serotonin-dopamine antagonist,
exacerbates symptoms of hallucinogen-persisting perception disorder
(3). Others note that SSRIs exacerbate flashbacks (4). In this case,
his perceptual disturbance symptoms responded to risperidone treatment.

For public safety, 5-MeO-DIPT is a controlled substance in several
countries. However, it is available in many areas, and the patient
obtained it through the Internet quite easily. We are concerned that
the abuse of 5-MeO-DIPT may be more widespread than previously
thought. We believe that studies are needed to verify the relationship
between 5-MeO-DIPT and hallucinogen-persisting perception disorder and
to call public attention to the toxicity of 5-MeO-DIPT.

References

Meatherall R, Sharma P: Foxy, a designer tryptamine hallucinogen. J
Anal Toxicol 2003; 27:313--317[Medline]

Strassman RJ: Adverse reactions to psychedelic drugs. J Nerv Ment Dis
1984; 172:577--595[Medline]

Morehead DB: Exacerbation of hallucinogen-persisting perception
disorder with risperidone. J Clin Psychopharmacol 1997;
17:327--328[CrossRef][Medline]

Markel H, Lee A, Holmes RD, Domino EF: LSD flashback syndrome
exacerbated by selective serotonin reuptake inhibitor antidepressants
in adolescents. J Pediatr 1994; 125:817--819[Medline].

Akifumi Ikeda, M.D., Kanako Sekiguchi, M.D., Kenichi Fujita, M.D.,
Ph.D., Hiroshi Yamadera, M.D., Ph.D., And Yoshihiko Koga, M.D., Ph.D.

Tokyo

Japan