Causes of Depression

by National Institute of Mental Health (NIMH)

(Page 2 of 7)

Co Occurrence of Depression with Other Illnesses

Depression can coexist with other illnesses. In such cases, it is important that the depression and each co occurring illness be appropriately diagnosed and treated.

Research has shown that anxiety disorders-which include post traumatic stress disorder (PTSD), obsessive compulsive disorder, panic disorder, social phobia, and generalized anxiety disorder-commonly accompany depression. Depression is especially prevalent among people with PTSD, a debilitating condition that can develop after exposure to a terrifying event or ordeal in which grave physical harm occurred or was threatened. Traumatic events that can trigger PTSD include violent personal assaults such as rape or mugging, natural disasters, accidents, terrorism, and military combat. PTSD symptoms include: re experiencing the traumatic event in the form of flashback episodes, memories, or nightmares; emotional numbness; sleep disturbances; irritability; outbursts of anger; intense guilt; and avoidance of any reminders or thoughts of the ordeal. In one NIMH supported study, more than 40 percent of people with PTSD also had depression when evaluated at one month and four months following the traumatic event.

Substance use disorders (abuse or dependence) also frequently co occur with depressive disorders.5,6 Research has revealed that people with alcoholism are almost twice as likely as those without alcoholism to also suffer from major depression.6 In addition, more than half of people with bipolar disorder type I (with severe mania) have a co occurring substance use disorder.

Depression has been found to occur at a higher rate among people who have other serious illnesses such as heart disease, stroke, cancer, HIV, diabetes, and Parkinson's. Symptoms of depression are sometimes mistaken for inevitable accompaniments to these other illnesses. However, research has shown that the co occurring depression can and should be treated, and that in many cases treating the depression can also improve the outcome of the other illness.

Causes of Depression

Substantial evidence from neuroscience, genetics, and clinical investigation shows that depressive illnesses are disorders of the brain. However, the precise causes of these illnesses continue to be a matter of intense research.

Modern brain imaging technologies reveal that, in depression, neural circuits responsible for the regulation of moods, thinking, sleep, appetite, and behavior fail to function properly, and critical neurotransmitters-chemicals that brain cells use to communicate- are out of balance. Studies of brain chemistry, including the effects of antidepressant medications, continue to inform our understanding of the biochemical processes involved in depression.

In some families, depressive disorders seem to occur generation after generation; however, they can also occur in people with no family history of these illnesses. Genetics research indicates that risk for depression results from the influence of multiple genes acting together with environmental or other nongenetic factors.

Very often, a combination of genetic, cognitive, and environmental factors is involved in the onset of a depressive disorder. Trauma, loss of a loved one, a difficult relationship, a financial problem, or any stressful change in life patterns, whether the change is unwelcome or desired, can trigger a depressive episode in vulnerable individuals. Later episodes of depression may occur without an obvious cause.

Men and Depression

Researchers estimate that at least six million men in the United States suffer from a depressive disorder every year.3 Research and clinical evidence reveal that while both women and men can develop the standard symptoms of depression, they often experience depression differently and may have different ways of coping with the symptoms. Men may be more willing to acknowledge fatigue, irritability, loss of interest in work or hobbies, and sleep disturbances rather than feelings of sadness, worthlessness, and excessive guilt. Some researchers question whether the standard definition of depression and the diagnostic tests based upon it adequately capture the condition as it occurs in men.

"I'd drink and I'd just get numb. I'd get numb to try to numb my head. I mean, we're talking many, many beers to get to that state where you could shut your head off, but then you wake up the next day and it's still there. Because you have to deal with it, it doesn't just go away. It isn't a two hour movie and then at the end it goes 'The End' and you press off. I mean it's a twenty four hour a day movie and you're thinking there is no end. It's horrible."

— Patrick McCathern, First Sergeant, U.S. Air Force, Retired

Men are more likely than women to report alcohol and drug abuse or dependence in their lifetime; however, there is debate among researchers as to whether substance use is a "symptom" of underlying depression in men or a co occurring condition that more commonly develops in men. Nevertheless, substance use can mask depression, making it harder to recognize depression as a separate illness that needs treatment.

Instead of acknowledging their feelings, asking for help, or seeking appropriate treatment, men may turn to alcohol or drugs when they are depressed, or become frustrated, discouraged, angry, irritable, and, sometimes, violently abusive. Some men deal with depression by throwing themselves compulsively into their work, attempting to hide their depression from themselves, family, and friends. Other men may respond to depression by engaging in reckless behavior, taking risks, and putting themselves in harm's way.

"When I was feeling depressed I was very reckless with my life. I didn't care about how I drove. I didn't care about walking across the street carefully. I didn't care about dangerous parts of the city. I wouldn't be affected by any kinds of warnings on travel or places to go. I didn't care. I didn't care whether I lived or died and so I was going to do whatever I wanted whenever I wanted. And when you take those kinds of chances, you have a greater likelihood of dying."

° Bill Maruyama, Lawyer

More than four times as many men as women die by suicide in the United States, even though women make more suicide attempts during their lives. In addition to the fact that men attempt suicide using methods that are generally more lethal than those used by women, there may be other factors that protect women against suicide death. In light of research indicating that suicide is often associated with depression, the alarming suicide rate among men may reflect the fact that men are less likely to seek treatment for depression. Many men with depression do not obtain adequate diagnosis and treatment that may be life saving.

More research is needed to understand all aspects of depression in men, including how men respond to stress and feelings associated with depression, how to make men more comfortable acknowledging these feelings and getting the help they need, and how to train physicians to better recognize and treat depression in men. Family members, friends, and employee assistance professionals in the workplace also can play important roles in recognizing depressive symptoms in men and helping them get treatment.

About the Author

www.nimh.nih.gov
The National Institute of Mental Health (NIMH) is one of 27 components of the National Institutes of Health (NIH), the Federal government's principal biomedical and behavioral research agency. NIH is part of the U.S. Department of Health and Human Services.