Experts initially thought that depression must be caused by low levels of neurotransmitters in the brain, in part because the first antidepressant drug — accidentally discovered in the 1950s — increased circulating amounts of the chemicals. Further research suggested that serotonin played an especially important role in mood. This so-called “chemical imbalance” theory gained a foothold in the cultural psyche and was promoted by ads for the medications.
However, starting in the 1990s, researchers began to understand that depression was much more complicated and that serotonin played only a nominal role. For one thing, S.S.R.I.s increase serotonin levels immediately, but it takes several weeks before people start to feel better. Studies also started to emerge showing that another brain system played a role: People with depression consistently have less volume in an area called the hippocampus that’s important for regulating mood.
The current prevailing theory, Dr. Hellerstein said, is that chronic stress can cause the loss of connections — called synapses — between cells in the hippocampus and other parts of the brain, potentially leading to depression. Antidepressants are now thought to work at least in part by helping the brain form new connections between cells. Researchers aren’t exactly sure how increasing serotonin with an S.S.R.I. causes these synapses to regrow. One possibility is that the medications also increase levels of other brain chemicals, called growth factors, that help those connections form and spread.
A paper published earlier this year made headlines for presenting several decades’ worth of evidence that people with depression don’t have less serotonin than people who are not depressed. To most psychiatrists, the paper didn’t reveal anything new, and it didn’t mean antidepressants aren’t effective (a widely held misinterpretation of the paper). Instead it revealed a fundamental disconnect between how the public viewed depression and how the experts thought about it.
Antidepressants Don’t Work the Way Many People Think
The most commonly prescribed medications for depression are somewhat effective — but not because they correct a “chemical imbalance.”
I was feeling in my mind a sensation close to, but indescribably different from, actual pain. This leads me to touch again on the elusive nature of such distress. That the word “indescribable” should present itself is not fortuitous, since it has to be emphasized that if the pain were readily describable most of the countless sufferers from this ancient affliction would have been able to confidently depict for their friends and loved ones (even their physicians) some of the actual dimensions of their torment, and perhaps elicit a comprehension that has been generally lacking; such incomprehension has usually been due not to a failure of sympathy but to the basic inability of healthy people to imagine a form of torment so alien to everyday experience. For myself, the pain is most closely connected to drowning or suffocation—but even these images are off the mark. William James, who battled depression for many years, gave up the search for an adequate portrayal, implying its near-impossibility when he wrote in The Varieties of Religious Experience: “It is a positive and active anguish, a sort of psychical neuralgia wholly unknown to normal life.”
And one of the most unendurable aspects of such an interlude was the inability to sleep. It had been my custom of a near-lifetime, like that of vast numbers of people, to settle myself into a soothing nap in the late afternoon, but the disruption of normal sleep patterns is a notoriously devastating feature of depression; to the injurious sleeplessness with which I had been afflicted each night was added the insult of this afternoon insomnia, diminutive by comparison but all the more horrendous because it struck during the hours of the most intense misery. It had become clear that I would never be granted even a few minutes’ relief from my full-time exhaustion.
Often, when Dr. Rosenthal talked about his research, someone would approach him to say that the same thing happened to them — but in the summer. In 1987, he and his colleagues published a report of 12 people who experienced a pattern of seasonal depression between March and October. This and subsequent work suggested that summer SAD presented differently than its winter counterpart, and might have different causes.
“Summer SAD is more of an agitated depression,” said Dr. Rosenthal, a clinical professor of psychiatry at the Georgetown University School of Medicine. While those with winter SAD tend to oversleep and overeat, summer SAD often shows up with insomnia and lowered appetite.
Seasonal Affective Disorder Isn’t Just for Winter
Feeling blue even though everyone seems to be basking in perfect summer weather? There might be a good reason for that.
In February of 1820, on learning that his good friend, Lady Georgiana Morpeth, was suffering from a bout of depression, noted essayist and clergyman Sydney Smith sent her the following precious letter, in which he listed twenty pieces of advice to help her overcome “low spirits.”
Foston, Feb. 16th, 1820
Dear Lady Georgiana,
Nobody has suffered more from low spirits than I have done – so I feel for you.
1st. Live as well as you dare.
2nd. Go into the shower-bath with a small quantity of water at a temperature low enough to give you a slight sensation of cold, 75° or 80°.
3rd. Amusing books.
4th. Short views of human life—not further than dinner or tea.
5th. Be as busy as you can.
6th. See as much as you can of those friends who respect and like you.
7th. And of those acquaintances who amuse you.
8th. Make no secret of low spirits to your friends, but talk of them freely—they are always worse for dignified concealment.
9th. Attend to the effects tea and coffee produce upon you.
10th. Compare your lot with that of other people.
11th. Don’t expect too much from human life—a sorry business at the best.
12th. Avoid poetry, dramatic representations (except comedy), music, serious novels, melancholy sentimental people, and every thing likely to excite feeling or emotion not ending in active benevolence.
13th. Do good, and endeavour to please everybody of every degree.
14th. Be as much as you can in the open air without fatigue.
15th. Make the room where you commonly sit, gay and pleasant.
16th. Struggle by little and little against idleness.
17th. Don’t be too severe upon yourself, or underrate yourself, but do yourself justice.
18th. Keep good blazing fires.
19th. Be firm and constant in the exercise of rational religion.
20th. Believe me, dear Georgiana, your devoted servant, Sydney Smith
(Source: The Selected Writings of Sydney Smith)
In fact, your thoughts often have much more to do with how you feel than what is actually happening in your life.
This isn’t a new idea. Nearly two thousand years ago the Greek philosopher, Epictetus, stated that people are disturbed “not by things, but by the views we take of them.” In the Book of Proverbs (23: 7) in the Old Testament you can find this passage: “For as he thinks within himself, so he is.” And even Shakespeare expressed a similar idea when he said: “for there is nothing either good or bad, but thinking makes it so” (Hamlet, Act 2, Scene 2).
Burns M.D., David D.. Feeling Good: The New Mood Therapy