Everyone occasionally feels blue or sad, but these feelings are usually fleeting and pass within a couple of days. When a person has a depressive disorder, it interferes with daily life, normal functioning, and causes pain for both the person with the disorder and those who care about him or her. Depression is a common but serious illness, and most who experience it need treatment to get better.
Many people with a depressive illness never seek treatment. But the vast majority, even those with the most severe depression, can get better with treatment. Intensive research into the illness has resulted in the development of medications, psychotherapies, and other methods to treat people with this disabling disorder.
Major depressive disorder, also called major depression, is characterized by a combination of symptoms that interfere with a person’s ability to work, sleep, study, eat, and enjoy once – pleasurable activities. Major depression is disabling and prevents a person from functioning normally. An episode of major depression may occur only once in a person’s lifetime, but more often, it recurs throughout a person’s life.
People with depressive illnesses do not all experience the same symptoms. The severity, frequency and duration of symptoms will vary depending on the individual and his or her particular illness. Symptoms include:
Persistent sad, anxious or “empty” feelings
Feelings of hopelessness and/or pessimism
Feelings of guilt, worthlessness and/or helplessness
Loss of interest in activities or hobbies once pleasurable, including sex
Fatigue and decreased energy
Difficulty concentrating, remembering details and making decisions
Insomnia, early-morning wakefulness, or excessive sleeping
Overeating, or appetite loss
Thoughts of suicide, suicide attempts
Persistent aches or pains, headaches, cramps or digestive problems that do not ease even with treatment
Depression often co-exists with other illnesses. Such illnesses may precede the depression, cause it, and/or be a consequence of it. It is likely that the mechanics behind the intersection of depression and other illnesses differ for every person and situation. Regardless, these other co-occurring illnesses need to be diagnosed and treated.
Anxiety disorders, such as post-traumatic stress disorder (PTSD), obsessive-compulsive disorder, panic disorder, social phobia and generalized anxiety disorder, often accompany depression. People experiencing PTSD are especially prone to having co-occurring depression. PTSD is a debilitating condition that can result after a person experiences a terrifying event or ordeal, such as a violent assault, a natural disaster, an accident, terrorism or military combat.
People with PTSD often re-live the traumatic event in flashbacks, memories or nightmares. Other symptoms include irritability, anger outbursts, intense guilt, and avoidance of thinking or talking about the traumatic ordeal. In a National Institute of Mental Health (NIMH) – funded study, researchers found that more than 40 percent of people with PTSD also had depression at one-month and four-month intervals after the traumatic event.
Alcohol and other substance abuse or dependence may also co-occur with depression. In fact, research has indicated that the co-existence of mood disorders and substance abuse is pervasive among the U.S. population.
Depression also often co-exists with other serious medical illnesses such as heart disease, stroke, cancer, HIV/AIDS, diabetes, and Parkinson’s disease. Studies have shown that people who have depression in addition to another serious medical illness tend to have more severe symptoms of both depression and the medical illness, more difficulty adapting to their medical condition, and more medical costs than those who do not have co-existing depression. Research has yielded increasing evidence that treating the depression can also help improve the outcome of treating the co-occurring illness.
There is no single known cause of depression. Rather, it likely results from a combination of genetic, biochemical, environmental, and psychological factors.
Research indicates that depressive illnesses are disorders of the brain. Brain-imaging technologies, such as magnetic resonance imaging (MRI), have shown that the brains of people who have depression look different than those of people without depression. The parts of the brain responsible for regulating mood, thinking, sleep, appetite and behavior appear to function abnormally. In addition, important neurotransmitters – chemicals that brain cells use to communicate – appear to be out of balance. But these images do not reveal why the depression has occurred.
Some types of depression tend to run in families, suggesting a genetic link. However, depression can occur in people without family histories of depression as well. Genetics research indicates that risk for depression results from the influence of multiple genes acting together with environmental or other factors.
In addition, trauma, loss of a loved one, a difficult relationship, or any stressful situation may trigger a depressive episode. Subsequent depressive episodes may occur with or without an obvious trigger.
Once diagnosed, a person with depression can be treated with a number of methods. The most common treatments are medication and psychotherapy.
Several types of psychotherapy – or “talk therapy” – can help people with depression. Some regimens are short-term (10 to 20 weeks) and other regimens are longer-term, depending on the needs of the individual.
Two main types of psychotherapies – cognitive behavioral therapy (CBT) and interpersonal therapy (IPT) – have been shown to be effective in treating depression. By teaching new ways of thinking and behaving, CBT helps people change negative styles of thinking and behaving that may contribute to their depression. IPT helps people understand and work through troubled personal relationships that may cause their depression or make it worse.
For mild to moderate depression, psychotherapy may be the best treatment option. However, for major depression or for certain people, psychotherapy may not be enough. Studies have indicated that for adolescents, a combination of medication and psychotherapy may be the most effective approach to treating major depression and reducing the likelihood for recurrence. Similarly, a study examining depression treatment among older adults found that patients who responded to initial treatment of medication and IPT were less likely to have recurring depression if they continued their combination treatment for at least two years.