A Quantitative Review of Cognitive Functioning in Homeless AdultsDepp, Colin A. PhD*†; Vella, Lea MS‡; Orff, Henry J. PhD*§; Twamley, Elizabeth W. PhD*§The Journal of Nervous and Mental Disease: February 2015 - Volume 203 - Issue 2 - p 126–131 doi: 10.1097/NMD.0000000000000248 Original Articles Abstract Author Information Homeless people experience elevated rates of risk factors for cognitive impairment. We reviewed available peer-reviewed studies reporting data from objective measures of cognition in samples identified as homeless. Pooled sample-weighted estimates of global cognitive screening measures, full-scale intelligence quotient (IQ), and premorbid IQ were calculated, in addition to pooled sample characteristics, to understand the representativeness of available studies. A total of 24 unique studies were identified, with 2969 subjects. The pooled estimate for the frequency of cognitive impairment was 25%, and the mean full-scale IQ score was 85, 1 standard deviation below the mean of the normal population. Cognitive impairment was found to be common among homeless adults and may be a transdiagnostic problem that impedes rehabilitative efforts in this population. Comparatively little data are available about cognition in homeless women and unsheltered persons. *Department of Psychiatry, University of California, San Diego; †Psychology Service, VA San Diego Healthcare System, California; ‡San Diego State University/University of California, San Diego, Joint Doctoral Program in Clinical Psychology; and §Center of Excellence for Stress and Mental Health, VA San Diego Healthcare System, California. Send reprint requests to Colin A. Depp, PhD, Department of Psychiatry (0664), University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0664. E-mail: firstname.lastname@example.org. Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.