New research discovers how antidepressants really work - they heal the brain

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New research discovers how antidepressants really work - they heal the brain

Prozac can work for people, but its success is because of a reason that no one ever realised. It literally heals the brain and stops it from dying.

Like many other antidepressants, Prozac increases the brain's supply of serotonin, a neurotransmitter. The drug's effectiveness inspired an elegant theory, known as the chemical hypothesis: Sadness is simply a lack of chemical happiness. The little blue pills cheer us up because they give the brain what it has been missing.

There's only one problem with this theory of depression: it's almost certainly wrong, or at the very least woefully incomplete.

Experiments have since shown that lowering people's serotonin levels does not make them depressed, nor does it worsen their symptoms if they are already depressed.

In recent years, scientists have developed a novel theory of what falters in the depressed brain. Instead of seeing the disease as the result of a chemical imbalance, these researchers argue that the brain's cells are shrinking and dying.

This theory has gained momentum in the past few months, with the publication of several high profile scientific papers.
The effectiveness of Prozac, these scientists say, has little to do with the amount of serotonin in the brain. Rather, the drug works because it helps heal our neurons, allowing them to grow and thrive again.

In this sense, Prozac is simply a bottled version of other activities that have a similar effect, such as physical exercise. They aren't happy pills, but healing pills.

These discoveries are causing scientists to fundamentally reimagine depression. While the mental illness is often defined in terms of its emotional symptoms - this led a generation of researchers to search for the chemicals, like serotonin, that might trigger such distorted moods - researchers are now focusing on more systematic changes in the depressed brain.

... Quote:
The best way to think about depression is as a mild neurodegenerative disorder. Your brain cells atrophy, just like in other diseases [such as Alzheimer's and Parkinson's]. The only difference with depression is that it's reversible. The brain can recover.
"says Ronald Duman, a professor of psychiatry and pharmacology at Yale.

One of the first cracks in the chemical hypothesis of depression came from a phenomenon known as the "Prozac lag." Antidepressants increase the amount of serotonin in the brain within hours, but the beneficial effects are not usually felt for weeks.

This led neuroscientists to wonder if something besides serotonin might be responsible. Duman, for instance, began to study a class of proteins known as trophic factors, which help neurons grow and survive. Trophe is Greek for nourishment; what sunlight and water do for trees, trophic factors do for brain cells.

Numerous studies had shown that chronic stress damages the brain by suppressing the release of trophic factors. In a series of influential papers published earlier this decade, Duman demonstrated that the same destructive hallmark is seen in depression, so that our neurons are deprived of what they need.
... Quote:
The mental illness occurs when these stress mechanisms in the brain spiral out of control.

Once that happens, the brain begins to shut itself down, suppressing all but the most essential upkeep. Not only do neurons stop growing, but the brain seems to stop creating new cells.
he said.

A recent study by Italian researchers, published in the journal Science, helps to reveal another mechanism by which antidepressants reverse the damage of depression.

The scientists were interested in seeing if fluoxetine, the active ingredient of Prozac, could increase the potential of brain cells in the adult rat.

They studied animals with severe cases of "lazy eye," a condition characterized by poor vision in one eye due to underdevelopment of the visual cortex. The scientists showed that fluoxetine gave brain cells the ability to take on new roles and form new connections, which erased the symptoms of the disorder.

... Quote:
The drug appears to make brain cells quite young. Even five years ago, this would have seemed like a very strange idea
says Jose Vettencourt, a lead author. The scientists are currently repeating the experiment with humans, raising the possibility that fluoxetine will soon be used to treat lazy eye and related conditions.

It is jarring to think of depression in terms of atrophied brain cells, rather than an altered emotional state. It is called "depression," after all. Yet these scientists argue that the name conceals the fundamental nature of the illness, in which the building blocks of the brain - neurons - start to crumble. This leads, over time, to the shrinking of certain brain structures, like the hippocampus, which the brain needs to function normally.

In fact, many scientists are now paying increased attention to the frequently neglected symptoms of people suffering from depression, which include problems with learning and memory and sensory deficits for smell and taste.

Other researchers are studying the ways in which depression interferes with basic bodily processes, such as sleeping, sex drive, and weight control. Like the paralyzing sadness, which remains the most obvious manifestation of the mental illness, these symptoms are also byproducts of a brain that's literally withering away.

More on the topic
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By netchicken: posted on 9-7-2008

Nice find! I've been learning a lot about mental illness lately, but I didn't realize it might go that deep. I can definitely see how being in a stressful, poor environment would strangle learning.
By peregrine: posted on 1-8-2008








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