Depression is one of the most common and treatable of all mental illnesses. The term ‘depression’ can be confusing and often referred to describe normal emotional reactions; however it is a widely studied psychological disorder that many people can suffer from. 340 million people in the world suffer from this mental disorder, which no one is immune to. It can happen to anybody from any social class, from any country, of any race.
Everybody can feel ‘down in the dumps’ at times. These feelings of sadness and discouragement are perfectly normal especially during hard times, but a person who constantly feels like this and cannot ‘snap out of it’ may be a sufferer of this illness. Depression can take several other forms. In bipolar disorder, known as manic-depressive illness, a person’s mood swings back and fourth between depression and mania.
People with seasonal effective disorder, suffer from depression normally during the autumn and winter when there are fewer hours of daylight. In dysthymia, people feel depressed, have low-self esteem, and concentrate poorly most of the time. This often lasts for years but is a lot milder than major depression. Mental health Professions use the term ‘clinical depression’ to refer to any of the forms of depression.
Although depression can happen at any age, it usually begins during a persons 20’s or 30’s. There are many symptoms of depression that can be feelings and emotions of everyday life for some people, however for a doctor to decide if somebody is clinically depressed the person must have 5 or more of the symptoms, that have lasted longer than 2 weeks, and be serious enough to cause worry and get in the way if the person’s work, social life or daily life. These symptoms include changes in appetite or weight, change in sleep patterns, restlessness or decreased activity, loss of energy or feeling tired all the time, experiencing a hard time concentrating or making decisions, feelings of worthlessness or guilt or repeated thoughts of death or suicide.
Depressed people might also have problems with digestion, such as a dry mouth, nausea, constipation or diarrhea. Being worried, anxious or irritable all the time could also be hidden signs of depression. In younger children symptoms may include physical complaints such as stomach ache or headaches, as well as irritability, social withdrawal and changes in eating habits. Elderly people with depression usually complain of physical rather than emotional problems, which can sometimes lead to doctors to misdiagnose the disorder. The symptoms can also differ due to different cultures. In Mediterranean cultures, for example, depressed people may complain of headaches or nerves, or in Asian cultures they may complain of weakness, fatigue or imbalance.
Modern medical research has contributed much to our understanding of depression. However scientists do not know the exact mechanism that triggers depressive illnesses. Doctors believed that depression was the result of thoughts and emotions that were troubling a person. Most recently, experts realized that there can be several factors working together that will lead a person to become depressed.
Many brain chemicals and hormones have been linked to the development of depression, meaning a person is depressed because of a biochemical imbalance, usually involved with the functioning of neurotransmitters that help different parts of the brain communicate with each other. There are many neurotransmitters each serving different purposes, but the three important ones that affect a persons mood is serotonin, noradrenalin and dopamine. Low levels of these chemicals have not been proven to cause depression, however, it is believed that elevation of these chemicals can improve the mood of a depressed person.
Suffers of depression were given a treatment in the form of an antidepressant drug that would boost serotonin and noradrenalin levels giving a 60% reduction in depressive symptoms. This shows brain chemicals and hormones are a strong factor, but as it is not proven in every case of depression there must also be other factors to take into consideration, which triggered theorists to conduct studies to try and determine what other factors could be associated with the causes of depression.
McGuffin et al (1996) conducted a study to see if it was possible that genetics was a component for depression. They studied identical (monozygotic, MZ) twins, which share 100% of their genes, with non-identical (dizygotic, DZ) twins who, like normal siblings, share around 50% of their genes. Out of the total of 109 pairs of twins he found that when a MZ twin was diagnosed with depression, there was a 46% chance that the other twin would receive the same diagnoses, whereas the figure for DZ twins was only 20%. The study supports the idea that a higher proportion of identical twins share the disorder, but as the percentage is no where near 100% it shows genetics can play a part but it can not be totally down to genetics.
Bierut et al (1999) conducted a twin study using a significant amount of twin pairs to determine the genetic factor. They used 2662 pairs and found a heritability factor of between 36% and 44%, but claimed environmental factors played a larger role. They also found that gender differences indicating lifetime prevalence of 31% for females and 19% for males, indicating females are more likely to suffer from the disorder.