INTERNATIONAL JOURNAL OF GERIATRIC PSYCHIATRY Int J Geriatr Psychiatry 2002; 17: 549–556. Published online in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/gps.641 The relationship between delusions and depression in Alzheimer’s disease Medhat M. Bassiony 1 , Andrew Warren 2,3 , Adam Rosenblatt 2,3 , Alva Baker 2,3 , Martin Steinberg 2,3 , Cynthia D. Steele 2,3 , Jeannie-Marie E. Sheppard 2 and Constantine G. Lyketsos 2,3 * 1 Department of Psychiatry, Faculty of Medicine, Zagazig University, Egypt 2 Neuropsychiatry Service, Department of Psychiatry and Behavioral Sciences, School of Medicine, The Johns Hopkins University, USA 3 Copper Ridge Institute, Sykesville, Maryland, USA SUMMARY Objectives The aim of this investigation was to study the relationship between delusions and depression in Alzheimer’s disease (AD). Design This was a cross-sectional, case control study. Setting Neuropsychiatry Service, the Johns Hopkins School of Medicine, USA. Participants 303 community-residing patients with probable AD according to NINCDS/ADRDA criteria were included in the study. Seventy-five patients with delusions only were compared to a control group of 228 patients who had neither delusions nor hallucinations. Patients with only hallucinations or both delusions and hallucinations were excluded. Measures Patients were assessed clinically for the presence of delusions using the DSM-IV glossary definitions. They were also rated on standardized measures of depression, cognitive impairment, staging of dementia, general medical health, and functional impairment. Results There was an association between delusions and depression among patients with AD. Before adjustment for other variables, the presence of depression conferred a 1.8-fold (95% confidence intervals (CI) ¼ 1.0–3.1; p ¼ 0.04) higher risk of delusions. After adjustment for multiple other variables, this risk increased further to 6.8-fold (95% CI ¼ 2.1–21.6; p ¼ 0.001). Conclusions Delusions in AD are strongly associated with depression after statistical adjustment for all confounding variables, which might distort this association. This finding has implications for our understanding of the etio-pathogenesis and management of delusions and depression in AD. Copyright # 2002 John Wiley & Sons, Ltd. key words — delusions; depression; Alzheimer’s disease; dementia INTRODUCTION Psychotic symptoms (delusions and hallucinations) occur commonly in Alzheimer’s disease (AD) (Wragg and Jeste, 1989; Ballard and Oyebode, 1995). These symptoms predict early institutionaliza- tion (Haupt and Kurz, 1993), worsen patient well being, and increase caregiver burden (Haupt and Kurz, 1996). Estimates for the prevalence of psychosis in dementia have varied from 16% (Burns et al., 1990) to 43% (Forstel et al., 1993). The reported pre- valence of delusions in AD patients has ranged from 10% to 73% (median 33.5%) (Wragg and Jeste, 1989). These estimates vary because of the different ways by which delusions and dementia have been diagnosed in different studies. Delusions in AD have been associated with older age (Cooper et al., 1991; Devanand et al., 1992; Ballard et al., 1995), male gen- der (Burns et al., 1990; Rockwell et al., 1994), less Received 6 January 2002 Copyright # 2002 John Wiley & Sons, Ltd. Accepted 6 January 2002 *Correspondence to: Dr C. G. Lyketsos, Osler 320, The Johns Hopkins Hospital, Baltimore, MD 21287, USA. Tel: 410-955-6158. Fax: 410-614-8760. E-mail: kostas@jhmi.edu Contract/grant sponsor: Depression in Alzheimer Disease Study (DIADS); contract/grant number: 1R01-MH56511.