* Supported by a Veterans Affairs Merit Review grant to Eileen M. Martin. We thank Roxanna Farinpour, Terri Harris, Mary Ellen Menken, Greg Renck, Lisa Sworowski, and Vibha Sabharwal for data collection and preparation; Gail Snukst-Torbeck and Gerald Nunnally for patient referrals; Alice Pau for pharmacologic data; and John Lackey for computer programming. Portions of the data were presented at Neuroscience of HIV-1 Infection: Basic and Clinical Frontiers, August 2-5, 1994, Vancouver, British Columbia. Address correspondence to: Eileen Martin, Department of Psychiatry (M/C 913), University of Illinois, 912 S. Wood St., Chicago, IL 60612, USA. E-mail: emartin@psych.uic.edu. Accepted for publication: July 7, 1999. Journal of Clinical and Experimental Neuropsychology 1380-3395/99/2105-730$15.00 1999, Vol. 21, No. 5, pp. 730-735 © Swets & Zeitlinger Reaction Times are Faster in HIV-Seropositive Patients on Antiretroviral Therapy: A Preliminary Report* Eileen M. Martin 1,3 , David L. Pitrak 2,3 , Richard M. Novak 2,3 , Kenneth J. Pursell 2,3 , and Kathleen M. Mullane 2,3 Departments of 1 Psychiatry and Neurology, 2 Medicine-Section of Infectious Disease, University of Illinois, Chicago, and 3 VA-Chicago Health Care System-West Side Division ABSTRACT We evaluated subclinical mental and motor slowing in 142 HIV-seropositive patients without dementia, using computerized simple and choice reaction time tasks and self-report measures of psychological dis- tress. Patients on antiretroviral therapy at the time of testing (n = 79) had significantly faster choice reac- tion times (p < 0.05), indicating faster mental processing speed, than untreated patients (n = 63). These faster RTs could not be attributed to differences in age, education, risk factors, degree of immunosuppres- sion, substance abuse history, peripheral neuropathy, or psychological distress. Reaction time tasks should be investigated further as potential outcome measures in clinical trials, particularly for subjects with few or no overt cognitive deficits. Mental slowing is a prominent characteristic of HIV-related dementia (Navia, Jordan & Price, 1986). Reaction time (RT) tasks developed in cognitive psychology are sensitive measures of subclinical HIV-related mental slowing. Perfor- mance on RT measures reliably discriminates HIV-seropositive gay men (E.M. Martin et al., 1992; Miller, Satz & Visscher, 1991; Wilkie et al., 1990) and injection drug users (E.M. Martin et al., 1995) without dementia from cohort- matched seronegative controls. Slowed RT per- formance correlates with CSF levels of quino- linic acid (A. Martin et al., 1992), which has been implicated in the pathophysiology of HIV- related dementia, and with decline in CD4 lym- phocyte counts (Bornstein et al., 1990). How- ever, there are few data available on reaction time performance of HIV-seropositive patients as a function of antiretroviral treatment status. Zidovudine (ZDV) crosses the blood-brain barrier (Klecker et al., 1987), and neuropsycho- logical and neurological studies confirm that ZDV therapy is associated with improved neuro- behavioral function. Schmitt et al. (1988) first reported that HIV-seropositive subjects’ neuro- psychological test performance improved during ZDV therapy. Investigators have since reported amelioration of symptoms of AIDS dementia complex in adults (Sidtis et al., 1993) and of HIV encephalopathy in children (Brouwers et al., 1990; Pizzo et al., 1988) during ZDV ther- apy. Patients on ZDV therapy also show im-