Suspiciousness as a speci®c risk factor for major depressive episodes in schizophrenia Erick Messias a , Brian Kirkpatrick a, * , Ranganathan Ram b , Allen Y. Tien c,d a Maryland Psychiatric Research Center, Department of Psychiatry, University of Maryland, Baltimore, MD, USA b Department of Psychiatry, State University of New York at Buffalo, Buffalo, NY, USA c Department of Psychiatry, Johns Hopkins University, Baltimore, MD, USA d Medical Decision Logic, Inc., Baltimore, MD, USA Received 19 November 1999; accepted 24 January 2000 Abstract Objective: Serious depression is a common and important complication of schizophrenia. In a prospective, population- based study, we tested the hypothesis that suspiciousness increases the risk for the later development of depression in schizophrenia. Method: Data came from the Epidemiological Catchment Area (ECA) study. Baseline clinical and demo- graphic features were used to predict the onset of new episodes of depression at 1 year follow-up. As ECA diagnoses were based on lay interviews, which may have low sensitivity compared with clinical diagnoses, two overlapping groups of putative schizophrenia patients were de®ned. Results: Suspiciousness was associated with an increased risk of new episodes of depression in both patient groups, after accounting for demographic variables. There was no association between an increased risk of depression and either disorganization or hallucinations and delusions. Conclusions: Suspicious- ness appears to be a speci®c risk factor for depression in psychotic groups. Interventions that decrease suspiciousness, or mitigate its isolating effects, might decrease the risk of serious depression and suicide. q 2001 Elsevier Science B.V. All rights reserved. Keywords: Depression; Risk factor; (Schizophrenia); Suspiciousness 1. Introduction Serious depression is one of the many painful consequences of schizophrenia. Not only are depressive episodes common among people who suffer from schizophrenia, but these episodes prob- ably make a major contribution to the high rate of suicide found in this group of patients (Wassink et al., 1999; Inskip et al., 1998; Hintikka et al., 1998), and depression may increase the risk of psychotic relapse (Mandel et al., 1982). Many factors associated with schizophrenia probably contribute to the etiology of depression. Schizophrenic patients frequently have serious, chronic stresses, including problems in developing and maintaining relationships (Addington et al., 1998), as well as dif®culties in functioning in other areas. It has also been proposed that abnormalities in brain dopaminergic systems play a more direct role in the etiology of depression in this group (Vijayakumar and Meti, 1999). The variance in clinical features, long-term Schizophrenia Research 47 (2001) 159±165 0920-9964/01/$ - see front matter q 2001 Elsevier Science B.V. All rights reserved. PII: S0920-9964(00)00030-X www.elsevier.com/locate/schres * Corresponding author. Tel.: 11-410-402-7662; fax: 11-410-402-7198. E-mail address: bkirkpatr@aol.com (B. Kirkpatrick).