LSDinduced hallucinogen persisting perception disorder treatment with clonidine an open pilot study

A pilot open study was conducted in order to evaluate the efficacy of clonidine in the treatment of LSDinduced 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 selfreport scale on the severity of symptoms graded 05. Patients scored an average of 5.25 SD 0.46 on the CGI and 4 on the selfreport 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 selfreport scale score was 2, indicating mild symptomatology. LSDrelated flashbacks associated with excessive sympathetic nervous activity may be alleviated with clonidine in some patients.