1. ¹Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
2. ²Stanley Foundation Research Center in Japan, Hamamatsu, Shizuoka, Japan
3. ³Department of Psychological Medicine, Institute of Psychiatry, London, UK
4. ⁴Department of Radiology, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan

Correspondence: Dr N Takei, Department of Psychiatry and Neurology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Hamamatsu, 431-3192 Shizuoka, Japan. Tel: +81 53 435 2295; Fax: +81 53 435 3621; E-mail address: ntakei@hama-med.ac.jp

Received 4 August 2003; Revised 23 January 2004; Accepted 27 January 2004; Published online 24 March 2004.

Abstract

Long-term toluene abuse causes a variety of psychiatric symptoms. However, little is known about abnormalities at the neurochemical level in the living human brain after long-term exposure to toluene. To detect neurochemical changes in the basal ganglia of subjects with a history of long-term toluene use, proton magnetic resonance spectroscopy (¹H MRS) was performed in 12 abstinent toluene users and 13 healthy comparisons with no history of drug abuse. N-acetylaspartate (NAA), creatine plus phosphocreatine (Cr+PCr), choline-containing compounds (Cho), and myo-inositol (MI) levels were measured in the left and right basal ganglia. The Cho/Cr+PCr ratio, a marker of membrane metabolism, was significantly increased in the basal ganglia of toluene users in comparison to that of the control subjects. Furthermore, the increase in the Cho/Cr+PCr ratio was significantly correlated with the severity of residual psychiatric symptoms. These findings suggest that long-term toluene use causes membrane disturbance in the basal ganglia, which is associated with residual psychiatric symptoms that persist even after long-term abstinence from toluene use.