The USA seems to be the world leader in both incidence and prevalence of major depression, and if anything, the rate is increasing.
In an Op-ED piece in today's New York Times, "Our Great Depression", Andrew Solomon argues that "We need a network of depression centers, much like the cancer centers established in the 1970s." He says:
DEPRESSION is the leading cause of disability worldwide, according to the World Health Organization. It costs more in treatment and lost productivity than anything but heart disease. Suicide is the 11th most common cause of death in the United States, claiming 30,000 lives each year...
Following this model, the National Institute of Mental Health should coordinate and subsidize a national network of depression centers, ideally based at research universities with good hospitals and departments devoted to the subject.
The University of Michigan, host to the country’s first national depression center, which opened its doors last month, has been a pioneer in this regard. More than 135 experts on depression and bipolar disorder will collaborate there, about half of them psychiatrists. The center has a large clinical treatment program and a genetic database that will house samples from tens of thousands of depressed and bipolar patients. It is sponsoring social and biological research and pressing for policy initiatives related to mental illness.
And finally adds "(Full disclosure: my father is the chief executive of a pharmaceutical company that manufactures antidepressants.)" His facts may be correct, but he is not an unbiased observer. And, the U of Michigan depression center certainly supports Cognitive Behavioral Therapy as much it supports pharmaceutical "solutions," so it is not just a thinly-disguised retail outlet for the largest company in Ann Arbor, Pfizer.
Still, while it is clear that "psychosocial factors" such as depression, isolation, and social support have a dramatic predictive value on the outcomes of "medical" disorders, such as cardiovascular disease, it is less clear to what extent depression is itself largely predicted by, or in some causal loop with these other social factors.
(See "Depression, Isolation, Social Support, and Cardiovascular Disease in Older Adults" by Heather M. Arthur, Journal of Cardiovascular Nursing, Vob 21, No. 55, pp S2-S7 for some links into the literature on the former subject.)
A different viewpoint can be found in literature off the continent, that is less supported by the pharmaceutical industry. Here's an example from the National Medical Journal of India
The cultures of depression.Jacob, KS
Department of Psychiatry, Christian Medical College, Vellore 632002, Tamil Nadu, India. firstname.lastname@example.org
Diverse frameworks, models and 'cultures' of depression have been postulated and promoted by psychiatrists, the pharmaceutical industry, general practitioners, primary care psychiatrists and the general population.
Psychiatrists and the pharmaceutical industry endorse the medical model while general practitioners and the public subscribe to social and psychological frameworks. [emphasis added]
These models are partial truths and should be viewed as complementary rather than competitive, some more valid in a specific context than others. The issues that need to be resolved include: (i) reexamination of the validity of the psychiatric diagnosis of depression in the primary care context; (ii) a review of the adequacy of a single label of depression to describe the diverse human context of distress; (iii) acknowledging the problems of using a symptom checklist in diagnosing depression; (iv) recognizing the need for psychosocial diagnostic formulations which clearly state the context, personality factors, acute and chronic stress and coping; (iv) highlighting the fact that antidepressant medication should be reserved for severe forms of distress; (v) re-emphasizing the need to manage stress and alter coping strategies in the treatment of people with such presentations; (vi) de-emphasizing medicalization of all forms of personal and social distress; (vii) focusing on other underlying causes of human misery including poverty, unmet needs and lack of rights. Clinically, there is a need to look beyond symptoms and explore personality, life events, situational difficulties and coping strategies in order to comprehensively evaluate the role of vulnerability, personality factors and stress in the causation of depression.
Possibly, however, we have simply run into the largest single reason to be considering systems thinking - namely, the occurrence of feedback in models of causation.
Standard statistical techniques are fine at dealing with open-loop causality, where A "causes" B, or B causes A, and there is a clearly defined start and end point. The General Linear Model covers that reasonably nicely.
But, as soon as you close that loop, so that A causes B which in turn causes A, that model breaks down. This behavior (a feedback loop) is very common in engineering, and no big deal, but it remains not only perplexing, but almost heretical in the epidemiological community. Even the mention of "psychosocial factors" for medical disorders causes tempers to flare and voices to be raised. The battles go on between arguments such as "bullets cause death" versus "guns cause death" versus "angry people who just happen to have guns at hand cause death" versus "bad economic and political situations cause massive unemployement and unhappiness and anger, which ultimately express themselves in gunshots which cause death."
Still, it seems a reasonable hypothesis to me that social factors, such as isolation and loneliness and lack of social support, result in depression; and, then that depression results in further actions or non-actions that increase isolation and lack of support; and, etc. in a mutually reinforcing feedback loop.
This is "hard to study" in the sense that people don't have desktop software that lets them compute such things as a "p-value" to distinguish whether they are being too credible, or not credible enough when looking at this possible causal loop to explain observational data.
The lack of such software is, of course, precisely the type of gap that the R21 research request for proposals I mentioned in earlier posts is designed to address. (I'm available to work on such a project if there are others also interested in a joint proposal.)
Why does this matter? It matters because it can completely change the interventions required to address the problem. If depression is largely an internal phenomenon, caused by genetics and bad wiring in the brain, that leads to one type of intervention - drugs and CBT. If depression is largely a social phenomenon, related to the well-documented collapse in social interaction documented by Putnam and the group at Duke, then personal intervention will simply deal with symptoms, and result in an ever growing prevalence of drug-dependent victims of social dysfunction - precisely the observation we find about the USA today.
In the latter case, what we need to address is why people are losing the ability to make friends, to keep friends, and to be a friend -- because it is that low-level breakdown that is emerging on a national scale as an epidemic of "depression."
The Duke study is "Social Isolation in America: Changes in core discussion networks over two decades" by Miller McPherson, Lynn Smith-Lovin and Matthew E. Brashears, American Sociological Reviews , (2006), vol 71, June (p 353-375)
Putnam's famous book is Bowling Alone: The Collapse and Revival of American Community by Robert D. Putnam (New York , Simon and Schuster, 2000).
As that site says,
In a groundbreaking book based on vast new data, Putnam shows how we have become increasingly disconnected from family, friends, neighbors, and our democratic structures-- and how we may reconnect.Sphere: Related Content
Putnam warns that our stock of social capital - the very fabric of our connections with each other, has plummeted, impoverishing our lives and communities. Putnam draws on evidence including nearly 500,000 interviews over the last quarter century to show that we sign fewer petitions, belong to fewer organizations that meet, know our neighbors less, meet with friends less frequently, and even socialize with our families less often. We're even bowling alone. More Americans are bowling than ever before, but they are not bowling in leagues. Putnam shows how changes in work, family structure, age, suburban life, television, computers, women's roles and other factors have contributed to this decline.