Depression is a mental disorder. It is more than just a low mood and is a serious condition that affects your physical and mental health.The causes may include a chemical imbalance in the brain or stressful life events. Now Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body. It can be said that people have depression before and after cancer, but could depression cause the cancer?
To answer this, we must first have an understanding as to what causes cancer. The majority of cancers, some 90–95% of cases, are due to environmental factors. The remaining 5–10% are due to inherited genetics.
The environmental factors include tobacco, diet and obesity, infections, radiation, stress, lack of physical activity and environmental pollutants. Hence there is no known evidence that depression can cause cancer but then again it is clear that a lot of factors that cause cancer could be associated with depression.
Some examples are:
==>Depressed individuals often have a tendency for reduced physical activity. Physical inactivity is believed to contribute to cancer risk, not only through its effect on body weight but also through negative effects on the immune system and endocrine system.
==>Victims of this mental illness also have an increased predisposition to smoking, alcoholism and substance abuse. Tobacco smoke causes 90% of lung cancer. It also causes cancer in the larynx, head, neck, stomach, bladder, kidney, esophagus and pancreas. Drinking alcohol regularly can increase the risk of at least 7 different cancers.
⇒ Depressed individuals are also subjected to a considerable amount of psychological stress. Psychological stress describes what people feel when they are under mental, physical, or emotional pressure. Although stress can cause a number of physical health problems, the evidence that it can cause cancer is weak. Some studies have indicated a link between various psychological factors and an increased risk of developing cancer, but others have not. One study even found that high stress levels can actually reduce the risk of breast cancer, by lowering oestrogen levels. And even in the event that stress and cancer are linked, the effects would be very small compared to other factors such as lifestyle, age or family history.
==>A team at Ohio State University say our own bodies help turn cancer against us by turning on a 'master switch' gene known as ATF3 which is expressed in response to stressful conditions in all types of cells,It is unclear exactly how, but the gene promotes the immune cells to act erratically and give cancer an escape route to other areas of the body.
Hence research does not exactly show a direct role of depression in the causation of cancer but the vice versa could be true.