Major depression is the most common chronic condition facing the primary care physician today. Of all patients visiting their doctor, 5-9% suffer from this disorder. The prevalence of major depression has increased since the 1950s in all age groups and psychiatrists have for many years debated whether this condition is caused by biological or behavioural factors. The debate has been between the use of drugs or therapies to combat this disorder. This debate has been misguided in so far as many diseases have both a biological and behavioural cause, including major depression. Paul A Kettl, MD Major depression, the forgotten illness.
The characteristic features of depression are feeling low, lethargy, and negative thought processes; sleep disorders and loss of appetite. Depression is more intense and sustained than ordinary sadness and involves feelings of ‘worthlessness, guilt and pessimism. ‘Unipolar depression’ can occur at any age and may appear gradually or suddenly. In Britain around fifty percent of adults between eighteen and seventy-four will experience serious depression. The number of people seeking help from their GPs for depression was nine million in 1998, (Bps 1999).
Bipolar disorder (Mania), generally appears in the early twenties, unlike depression (which is more common in women), Cochrane (1995), bipolar disorder is equal in both men and women, although it is less common than depression. Interestingly there is a disproportionately higher incidence of bipolar disorder among creative people Jamison (1989). For example of forty-seven award winning British writers and artists thirty eight percent were treated for the disorder, the figure in the general population is about one percent.
Genetic factors play a major role in the probability of some people experiencing depression occurring in about one in every hundred people. These genetic traits are not always detrimental to the person, as in some cases the incidence of bipolar disorder can be advantageous to some creative people, Jamison, (1989). The connection between anxiety and depression is almost one hundred percent, Kendler et, al, (1992), which suggests the genes responsible for anxiety are almost certainly responsible for depression also. In general it seems that anxiety results from anticipation of loss whereas depression is a result of loss Hamer and Copeland, (1999). William Scheftner, MD, medical director for research at the (Rush Institute for Mental Well-Being), states that.
‘Inherited depressions are transmitted by genetic material or DNA, which is present at the moment of birth. These genes are located on chromosomes, what isn’t clear is which gene or how many genes are involved. This study is designed to be the first of many steps in identifying the locations of the genes for unipolar major depressive disorder. Once they are located, we can then begin to develop tests that will provide earlier diagnosis and determine how the genes biochemically cause depression’.
The neurotransmitter serotonin appears to play a significant role in depressive disorders. Studies of Vervet monkeys found that the alpha male in the group had levels of serotonin twice as high as lower males in the group, Raleigh, McGuire (1991). When the alpha male lost the position of head of the group the serotonin levels dropped significantly and they showed signs of depression. Anti depressant drugs such as Fluoxetine, (Prozac), can reverse the loss of serotonin and when administered to a random male that male became the new alpha male of the group. This research suggests that serotonin plays a role in the hierarchical system, which leads on to the importance of the position held in the hierarchical system and that some low mood is natural in the hierarchical system.
Some evidence suggests that we may be in an epidemic of depression. Ness and Williams, (1996), examined thirty nine thousand people in five different parts of the world and found that young people have far more episodes of depression than their elders, furthermore, depression is more common in societies with greater degrees of economic development. Reasons cited for this phenomena is worries about environmental change, economic uncertainty and increasing hierarchical competition. The development of mass communication means that we now compete on the world stage and against the best in the world. All these factors are potential triggers for a depressive episode.
An optimistic or pessimistic view of modern society can also play a major role in the onset of depressive disorder. Behavioural explanations focus on the role played by reinforcement, Ferster, (1995). Lewinshon, (1974), argues that the social inactivity of people with depression leads to a concerned attention from loved ones and friends which reinforces the depressed behaviour, after care and attention wane this exacerbates the depression in a cyclic degeneration. Lewinshon also points to positive reinforcement as part of a healthy interactive need in people. Depressed people report having fewer pleasant experiences than non- depressed people. Fewer pleasant reinforcing experiences implies that people who become depressed lower their participation in positive reinforcement.