Does anxiety increase impulsivity in patients with bipolar disorder or major depressive disorder? Marcella Bellani a, b, * , John P. Hatch c, d , Mark A. Nicoletti a , Astrid E. Ertola e , Giovana Zunta-Soares a , Alan C. Swann a , Paolo Brambilla f, g , Jair C. Soares a a UT Center of Excellence on Mood Disorders, Department of Psychiatry and Behavioral Sciences, UT Houston Medical School, Houston, TX, USA b Department of Public Health and Community Medicine, Section of Psychiatry and Clinical Psychology, Inter-University Centre for Behavioural Neurosciences (ICBN), University of Verona, Verona, Italy c Department of Psychiatry, The University of Texas Health Science Center at San Antonio, USA d Department of Developmental Dentistry, The University of Texas Health Science Center at San Antonio, USA e School of Psychology, Fielding Graduate University, CA, USA f DISM, Inter-University Center for Behavioural Neurosciences (ICBN), University of Udine, Udine, Italy g IRCCS “E. Medea” Scientific Institute, Udine, Italy article info Article history: Received 6 August 2011 Received in revised form 18 November 2011 Accepted 12 January 2012 Keywords: Anxiety Impulsivity Bipolar disorder Major depressive disorder abstract The objective of this study was to examine whether anxiety increases impulsivity among patients with bipolar disorder (BPD) and major depressive disorder (MDD). Subjects comprised 205 BPD (mean age Æ SD 36.6 Æ 11.5 y; 29.3% males) and 105 with MDD (mean age Æ SD 38 Æ 13.1 y; 29.5% males) diagnosed using the DSM-IV-SCID. Impulsivity was assessed with the Barratt Impulsivity Scale and anxiety with the Hamilton Anxiety Rating Scale. Comorbid anxiety disorders were present in 58.9% of the BPD and 29.1% of MDD. BPD were significantly more impulsive than MDD (p < 0.001), and both BPD and MDD subjects showed significantly higher impulsivity when anxiety was present either as a comorbidity (p ¼ 0.010) or as a symptom (p ¼ 0.011). Impulsivity rose more rapidly with increasing anxiety symptoms in MDD than in BPD. The presence of anxiety, either as a comorbid disorder or as current anxiety symptoms, is associated with higher impulsivity in subjects with either BPD or MDD. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Bipolar disorder (BPD) and major depressive disorder (MDD) are the two most prevalent major mood disorders with a prevalence of about 1% and 6.7%, respectively (Kessler et al., 1994; Waraich et al., 2004). Psychiatric comorbidities are common in both disorders. Two-thirds of patients with BPD are estimated to have a second Axis 1 disorder (McElroy et al., 2001), with anxiety disorders being one of the most burdensome and frequent comorbidities (Simon et al., 2004; Goldstein and Levitt, 2007). The presence of comor- bid anxiety often complicates the presentation and the course of BPD. For instance, BPD patients with a comorbid anxiety disorder have a lower quality of life (Kauer-Sant’Anna et al., 2007), more severe symptoms (Gaudiano et al., 2005), poorer treatment response (Feske et al., 2000) especially to mood stabilizers (Zutshi et al., 2006), increased rates of hospitalization, and longer recovery time from depression (Otto et al., 2004; Coryell et al., 2009). In addition, anxiety disorders in BPD predict suicidal ideation, suicidal attempts and completed suicide (Engstrom et al., 2004; Simon et al., 2007a,b). Comorbid anxiety is also common in patients with unipolar depression. Nearly 50% of MDD patients also meet criteria for anxiety disorders (Zimmerman et al., 2000). MDD frequently is worsened by the presence of a comorbid anxiety disorder (Otte, 2008) and is associated with longer admissions, lower psychoso- cial functioning (Petersen et al., 2009; Brown et al., 1996), poorer response to antidepressants (Farabaugh et al., 2005), and higher rate of suicidal ideation (Fava et al., 2004). Moreover MDD and generalized anxiety disorder (GAD), are known to share most of their genetic risk factors (Kendler, 1992). In addition to comorbid anxiety disorders, anxiety symptoms themselves are strongly associated with suicidality after controlling for different comorbid psychiatric diagnoses (Diefenbach et al., 2009; Saaren et al., 2005). However, the role of anxiety in mood disorders has mostly been studied as a comorbidity, and less is known about the role of anxious symptoms in mood disorders. * Corresponding author. Department of Public Health and Community Medicine, Section of Psychiatry and Clinical Psychology, University of Verona, Piazzale L.A. Scuro, 10, 37134 Verona, Italy. Fax: þ39 045 802 7498. E-mail address: marcella.bellani@univr.it (M. Bellani). Contents lists available at SciVerse ScienceDirect Journal of Psychiatric Research journal homepage: www.elsevier.com/locate/psychires 0022-3956/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.jpsychires.2012.01.016 Journal of Psychiatric Research 46 (2012) 616e621