Contents lists available at ScienceDirect Psychiatry Research journal homepage: www.elsevier.com/locate/psychres The association between immune markers and recent suicide attempts in patients with serious mental illness: A pilot study Faith Dickerson a, ⁎ , Maria Adamos a , Emily Katsafanas a , Sunil Khushalani a , Andrea Origoni a , Christina Savage a , Lucy Schweinfurth a , Cassie Stallings a , Kevin Sweeney a , Armin Alaedini b , Melanie Uhde b , Emily Severance c , Holly C. Wilcox d , Robert Yolken c a Stanley Research Program, Sheppard Pratt Health System, Baltimore, MD, USA b Department of Medicine, Columbia University, New York, NY, USA c Stanley Neurovirology Laboratory, Johns Hopkins School of Medicine, Baltimore, MD, USA d Department of Psychiatry and Behavioral Sciences, Johns Hopkins School of Medicine, Baltimore, MD, USA ARTICLE INFO Keywords: Suicide Attempted Biomarkers Inflammation Gastrointestinal ABSTRACT Previous studies have identified elevations in markers of gastrointestinal inflammation in schizophrenia and mood disorders but studies have not measured the association between these markers and recent suicide attempts. We assessed 210 patients receiving treatment for schizophrenia, bipolar disorder, or major depression. We employed the Columbia Suicide Severity Rating Scale to identify recent and lifetime suicide attempts (actual, aborted, and interrupted). Psychiatric participants and a control group of 72 individuals without a psychiatric disorder had a blood sample drawn from which were measured specific markers of gastrointestinal inflammation and also C-Reactive protein (CRP). A total of 20 (10%) of psychiatric participants had a suicide attempt in the previous one month and 95 (45%) an attempt during their lifetime but not in the previous one month. The recent attempters had significantly elevated levels of antibodies to yeast mannan from Saccharomyces cerevisiae (ASCA), the food antigen gliadin, and bacterial lipopolysaccharide (LPS) compared with the non-psychiatric group when adjusting for demographic and clinical variables. These markers were not elevated in individuals with a past, but not recent, suicide attempt history. Our study indicates that there is evidence of gastrointestinal inflammation in some individuals who have had a recent suicide attempt. 1. Introduction Psychological autopsy and epidemiological studies indicate that more than 90% of people who die by suicide have a diagnosable psychiatric illness, particularly major depression, bipolar disorder, or schizophrenia (Cavanagh et al., 2003; Nordentoft et al., 2011). Genetic factors, independent of those associated with psychiatric disorders, may also play a role in suicide but genes of large effect have yet to be identified (Mullins et al., 2014). The ability to predict suicide attempts based on clinical factors remains limited (Zalsman et al., 2016). Currently available biomarkers also have limited predictive value (Oquendo et al., 2014). The identification of blood-based markers would provide for more personalized methods for the assessment and treatment, and ultimately prevention, of suicide attempts. Many individuals with schizophrenia and mood disorders have evidence of immune activation suggesting that immune dysregulation may be part of the etiopathology of these disorders (Gibney and Drexhage, 2013; Haapakoski et al., 2016; Leboyer et al., 2016; Severance et al., 2015). Studies by our group and others indicate that the gastrointestinal tract is often the primary source of this immune activation as evidenced by increased levels of markers of gastrointest- inal inflammation in individuals with serious mental illness (Kiecolt- Glaser et al., 2015; Petra et al., 2015; Severance et al., 2015). These markers have varying degrees of prevalence and intercorrelations (Severance et al., 2013, 2014). Furthermore, increased rates of suicide and suicide attempts have been found in some populations of indivi- duals with celiac disease (Ludvigsson et al., 2011) or inflammatory bowel diseases (Gradus et al., 2010). Several of these immune markers have been the focus of our recent investigations. Gliadin is a component of gluten, found in wheat and related cereals. Antibody response to dietary gliadin is associated with celiac disease, an immune-mediated enteropathy, and with non-celiac wheat sensitivity (Uhde et al., 2016) and is thought to indicate intestinal inflammation and/or intestinal barrier dysfunction. We have http://dx.doi.org/10.1016/j.psychres.2017.05.005 Received 20 January 2017; Received in revised form 25 April 2017; Accepted 4 May 2017 ⁎ Corresponding author. E-mail address: fdickerson@sheppardpratt.org (F. Dickerson). Psychiatry Research 255 (2017) 8–12 Available online 09 May 2017 0165-1781/ © 2017 Published by Elsevier Ireland Ltd. MARK