Abstract: Objective: The implantable cardioverter defibrillator (ICD) is used to treat life-threatening ventricular arrhythmias and in the prevention of sudden cardiac death. A significant proportion of ICD patients experience psychological symptoms including anxiety, depression or both, which in turn can impact adjustment to the device. The objective of this systematic review was to assess the prevalence of anxiety and depression or symptoms of anxiety and depression among adults with ICDs.Methods: Search of MEDLINE®, CINAHL®, PsycINFO®, EMBASE® and Cochrane® for English-language articles published through 2009 that used validated diagnostic interviews to diagnose anxiety or depression or self-report questionnaires to assess symptoms of anxiety or depression in adults with an ICD.Results: Forty-five studies that assessed over 5000 patients were included. Between 11% and 28% of patients had a depressive disorder and 11–26% had an anxiety disorder in 3 small studies (Ns=35–90) that used validated diagnostic interviews. Rates of elevated symptoms of anxiety (8–63%) and depression (5–41%) based on self-report questionnaires ranged widely across studies and times of assessment. Evidence was inconsistent on rates pre- versus post-implantation, rates over time, rates for primary versus secondary prevention, and for shocked versus non-shocked patients.Conclusion: Larger studies utilizing structured interviews are needed to determine the prevalence of anxiety and depression among ICD patients and factors that may influence rates of anxiety and depressive disorders. Based on existing data, it may be appropriate to assume a 20% prevalence rate for both depressive and anxiety disorders post-ICD implant, a rate similar to that in other cardiac populations.