Depression, clinically speaking by the Harvard Medical School definition is depression results from a chemical imbalance. Research indicates that as many as 50 percent of Veterans experience significant difficulty acclimating with a third developing mental health problems including depression.

But experts contend this definition of depression doesn’t capture how complex the disease is. More research suggests that depression doesn’t originate from having too much or too little of certain brain chemicals. Rather, there are numerous possible causes of depression, including faulty mood regulation by the brain, genetic vulnerability, stressful life events, medications, and medical problems. It’s believed that several of these forces interact to bring on depression. For more information, click HERE.

The U.S. Army said depression includes stress, bereavement, pain, sleep apnea, anemia, thyroid disorders, medication side effects, and genetic factors and since there are so many causes and contributing factors, it is important to discuss changes in mood, energy, or motivation with a medical professional, the Army said.

Anxiety is closely related to depression and people with depression may experience increases in their anxiety levels. Males also tend to display irritability as a presenting symptom of depression.