G Davis1, N Baboolal2, A McRae1, R Stewart3. 1. Department of Paraclinical Sciences, Faculty of Medical Sciences, The University of the West Indies, St. Augustine Campus, Trinidad, W.I. 2. Department of Clinical Medical Sciences, Faculty of Medical Sciences, The University of the West Indies, St. Augustine Campus, Trinidad, W.I. 3. Department of Psychological Medicine, Institute of Psychiatry, Psychology and Neuroscience, De Crespigny Park, London, UK.