|Depression and Cancer...(page 3)|
|How is clinical depression diagnosed? |
Current criteria for diagnosing clinical depression rely mostly on the presence of several core symptoms, in particular low mood, loss of interest in usual activities, inability to experience pleasure, sleep disturbance and fatigue. These symptoms should be present for at least two weeks before a diagnosis is made.
However, many doctors who are treating cancer patients favor eliminating the physical symptoms (fatigue, sleep disturbance, low energy, poor appetite) when diagnosing clinical depression, because these symptoms may be caused by cancer or some of the treatments used to combat it. In this way, we can be sure that we are not diagnosing depression when it really does not exist. As an alternative to the physical symptoms, many clinicians rely more on the use of mood, cognitive and behavioral symptoms.
Clinical depression can be mild, moderate or severe. The most severe form is called major depression and it is often quite incapacitating. Patients with major depression have most of the symptoms of clinical depression and they may not be able to carry out their usual responsibilities, such as going to work. Many persons with milder forms of depressive illness are less incapacitated and may not recognize their problem, so they may not seek treatment. Sometimes patients with milder forms of depression blame themselves for "not trying hard enough" and they may be embarrassed about seeking help. An important element of clinical depression as contrasted with sad mood is that because it is a biological disorder, patients with clinical depression usually do not get better with encouragement and social support alone, but often need antidepressant medication.
Can clinical depression cause or worsen cancer?
Studies have shown that clinical depression can worsen the disability caused by cancer. For example, the fatigue caused by depression can worsen the fatigue caused by treatments such as radiation therapy. Clinical depression can also impair the quality of life of cancer patients. It may deprive them of the ability to enjoy life's pleasures at a time when they may be stressed by their illness. It may also affect the motivation needed to endure cancer treatments and the ability to be optimistic and hopeful about the outcome of treatment. Family members may become frustrated by a depressed patient's withdrawal or have difficulty in understanding a patient's negative feelings when they themselves are trying to be optimistic and have a positive outlook about the illness.
At one time it was also believed that there was a relationship between cancer onset and progression and clinical depression. Some early studies suggested that individuals who were more hopeless were thought to have a lowered chance of survival from cancer.
Recent studies appear to have seriously put into question these early observations. For example, a recent study from Denmark showed that among 67,000 women who were treated for depression, there was no increased likelihood of developing breast cancer beyond that which would be expected for each age group. Likewise, a recent review of the literature on depression concluded that the condition does not seem to increase the risk of death from cancer. Although this issue has not completely been laid to rest, these recent findings should provide some reassurance to cancer patients who may have clinical depression or be occasionally demoralized and who are worried about how this will affect their illness.
In summary, while clinical depression is more common in cancer patients, it is by no means universal nor is it "normal" to be clinically depressed. While it is normal to be sad, frustrated or even angry, clinical depression is a treatable biological disorder.
Dr. Baile is chief of psychiatry at M.D. Anderson Cancer Center in Houston.