1. Institute of Neuroscience & Physiology, Department of Psychiatry & Neurochemistry, The Sahlgrenska Academy at the University of Gothenburg, S-431 80 Mölndal, Sweden and Laboratory of Clinical Chemistry, Sahlgrenska University Hospital, S-413 45 Gothenburg, Sweden
2. Institute of Neuroscience & Physiology, Department of Psychiatry & Neurochemistry, The Sahlgrenska Academy at the University of Gothenburg, S-431 80 Mölndal, Sweden and Laboratory of Clinical Chemistry, Sahlgrenska University Hospital, S-413 45 Gothenburg, Sweden and UCL London, Institute of Neurology, Queen Square, London WC1N 3BG, UK.