Although anxiety and depression are different disorders, they often produce similar symptoms, such as nervousness, irritability, trouble concentrating and problems sleeping.

Anxiety disorders are the most common mental illness in the United States, affecting 40 million adults (18 percent of the population) aged 18 and older. As for depression, in 2015, an estimated 16.1 million adults aged 18 or older in the U.S. had at least one major depressive episode in the past year, representing 6.7 percent of all adults.

We all may have an occasional bout of depression and/or anxiety, but when these feelings are persistent, they affect many aspects of our lives — even cardiac health.

Studies have shown that major depressive disorder (MDD) increases the risk of cardiovascular morbidity and mortality by about 80 percent, independent of other risk factors. Among those with heart disease, 20 percent to 40 percent have elevated depressive symptoms, and 15 percent to 20 percent suffer from MDD. Over 50 percent of patients with heart failure have elevated rates of anxiety, with 13 percent having anxiety disorder.

A recent article in Psychiatric Times highlights the associations between psychiatric illness and cardiac health, along with diagnostic approaches in this patient population and treatments that are safe and effective.

Depression is associated with the development of atherosclerosis and heart failure, and the evidence for cardiac health is so strong that the American Heart Association (AHA) labeled depression a risk factor for poor medical outcomes following acute coronary syndrome. Anxiety disorders such as generalized disorder (GAD), panic disorder and post-traumatic stress disorder (PTSD) have also been associated with increased risk for coronary artery disease and heart failure.

Depression, anxiety and cardiovascular diseases may frequently co-occur because of related drivers such as unhealthy lifestyles, autonomic dysregulation, hypothalamic-pituitary-adrenal (HPA) axis dysregulation, endothelial dysfunction and inflammation.

Studies show that those with anxiety and depression are more likely to smoke and drink known risk factors for cardiovascular disease and that they are less likely to exercise. People suffering from depression consume more calories daily and often are deficient in vitamins D and B12, possibly contributing to metabolic dysregulation. Chronic stress may lead to inflammation.

Because there may be an overlap of cardiac and psychiatric symptoms, it is important to evaluate patients both medically and psychiatrically (DSM-5 diagnostic criteria) to make a true psychiatric disorder diagnosis and ensure that underlying medical disorders are not misdiagnosed. The AHA has developed guidelines that outline a screening pathway for depression in patients with cardiac disease.

The mainstays of pharmacologic interventions in treating depression and anxiety in cardiac disease include antidepressant medications, especially selective serotonin reuptake inhibitors (SSRIs) rather than tricyclic antidepressants (TCAs), which can have significant cardiovascular adverse effects. However, psychotherapy is often an alternative treatment for depression and anxiety in patients with cardiac disease in an effort to avoid medication interactions and possible adverse events.

While depression and anxiety disorders are common and concerning in patients with cardiovascular disease because of poor outcome, an accurate clinical diagnosis followed by safe and effective treatments are critical to improving not only psychiatric health but also patients' daily living as well as functional and cardiac outcomes.