1. ¹Molecular Neuropsychiatry Section, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA
2. ²Treatment Section, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, USA

Correspondence: Dr RI Herning, Molecular Neuropsychiatry Section, National Institute on Drug Abuse/IRP, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA. Tel: +1 410 550-1551; E-mail: rherning@intra.nida.nih.gov

Received 24 February 2002; Revised 11 September 2002; Accepted 16 September 2002.

Abstract

Opiate replacement therapy has been useful in reducing heroin use and in keeping patients in treatment programs. However, neuropsychological and neurophysiological effects of this treatment regimen have not been evaluated systematically. To determine whether methadone treatment reduces the magnitude of cerebral blood flow alternations in polysubstance (heroin and cocaine) abusers, we compared blood flow parameters in control subjects (n=26), polysubstance abusers (n=28) maintained on methadone for 24 weeks, and polysubstance abusers (n=22) who were not seeking treatment. Blood flow velocity was recorded from the anterior and middle cerebral arteries using transcranial Doppler sonography on an outpatient visit. The pulsatility index, a measure of cerebrovascular resistance, was significantly (p<0.05) increased in both groups of polysubstance abusers compared to control subjects. Increased pulsatility in the two groups of substance abusers suggests constriction of the small cortical arteries. Nevertheless, the methadone-maintained polysubstance abusers had significantly lower pulsatility values than the nontreatment substance-abusing group. These findings suggest that maintenance on methadone might have significant beneficial neurovascular effects on this population of patients.