LSD-induced hallucinogen persisting perception disorder treatment with clonidine: an open pilot study

A small pilot open study tested whether clonidine, a drug that reduces sympathetic nervous activity, could help people with hallucinogen persisting perception disorder (HPPD) caused by LSD. Eight patients who had had HPPD for at least three months and had been drug-free for at least three months took a low dose of clonidine (0.025 mg three times daily) for two months. Two patients dropped out. Among the six who completed the study, scores on the Clinical Global Impression Scale dropped from an average of 5.25 (severe) to 2.5 (mild), and self-reported symptom severity fell from 4 to 2 on a 0-5 scale. The findings suggest that clonidine may alleviate LSD-related flashbacks linked to excessive sympathetic nervous activity in some patients.

Study at a glance

Abstract

A pilot open study was conducted in order to evaluate the efficacy of clonidine in the treatment of LSD-induced hallucinogen persisting perception disorder (HPPD). Eight patients fulfilled entrance criteria. All complained of HPPD for at least 3 months and were drug free at least 3 months. They received fixed low doses of clonidine, 0.025 mg, three times a day for 2 months. They were evaluated by the Clinical Global Impression Scale (CGI) and a self-report scale on the severity of symptoms (graded 0-5). Patients scored an average of 5.25 (SD = 0.46) on the CGI and 4 on the self-report scale at baseline, indicating marked psychopathology. One patient dropped out at week 3 and a second patient dropped out at week 5. Of the six patients remaining at the end of 2 months, the average CGI score was 2.5 (SD = 0.55) and the self-report scale score was 2, indicating mild symptomatology. LSD-related flashbacks associated with excessive sympathetic nervous activity may be alleviated with clonidine in some patients.