psychotherapy: If you thought depression was caused by low serotonin levels, think again. It looks as if the brain chemistry of a depressed person is much more complex, with mounting evidence suggesting that too much serotonin in some brain regions is to blame.
If correct, it might explain some of the negative side-effects associated with selective serotonin re-uptake inhibitors (SSRIs), antidepressants like Prozac which increase the amount of the neurotransmitter serotonin in some parts of the brain.
The traditional view of depression was largely based on the observation that SSRIs boost mood- although why they do so is unknown. “Because antidepressants increase serotonin in some parts of the brain, people assumed that depression must be the result of low serotonin levels,” says Christopher Lowry of the University of Boulder in Colorado. But the discovery of multiple types of serotonin-releasing neurons in the brain, along with high levels of serotonin recorded in people with depression, is prompting a rethink.
“What’s more likely is that there are subgroups of serotonin neurons that are overactive in depressed patients, rather than underactive as we have all been assuming,” says Lowry.
One of the first clues that something might be amiss with the traditional theory came three years ago, when Murray Esler at the Baker Heart Research Institute in Melbourne, Australia, and colleagues found that the level of serotonin in the brains of people with panic disorder was four times higher than in healthy volunteers (Stress, DOI: 10.1080/10253890701300904), and in depressed people who were not receiving treatment it was two times higher than in volunteers (Archives of General Psychiatry, vol 65, p 38). They also showed that long-term use of SSRIs in people with depression and panic disorder seemed to decrease serotonin levels through an as yet unidentified mechanism.
Now, in studies of rats and mice, Lowry has found that there are multiple types of serotonin neurons that can be independently regulated. He presented his results at the Forum of European Neuroscience in Amsterdam, the Netherlands, last week.
This fits well with findings from other groups that there are two types of serotonin receptor in the amygdala, a brain region linked to emotion and anxiety: 5-HT2A receptors that inhibit anxiety, and 5-HT2C receptors that promote it. The roles of the receptors were identified by injecting drugs that either stimulated or inhibited each receptor and observing the animals’ behavioural response.
Together, the findings might mean that while high levels of serotonin in some brain regions like the prefrontal cortex can lead to improved mood, high serotonin in other regions could have negative effects.
Evidence for this idea comes from Gina Forster at the University of South Dakota in Vermillion and colleagues, who injected a stress-related molecule into the brains of rats and found that it triggered two phases of serotonin release. An initial wave of serotonin appeared to increase fear-like behaviour in the rats, while a second wave decreased this behaviour, possibly because it activated a brain region called the medial prefrontal cortex, which is associated with calming of fears (Neuroscience, vol 141, p 1047).
The new findings have implications for how SSRI drugs work. In the long-term, SSRIs do tend to have a calming effect, although more research is needed to understand how they do this.
However, in the short-term some people taking SSRIs report feeling increased anxiety. This is “almost certainly due to the activation of one of these groups of serotonin neurons”, says Lowry. The suicidal thoughts some people taking SSRIs claim to experience may also be linked to boosting serotonin, as suicide is thought to be associated with increased impulsivity. “It may be that certain types of SSRI are affecting these impulsivity circuits in the brain,” says Lowry.
Learning more about these different groups of serotonin neurons could lead to better treatments for depression and anxiety disorders. “It might be possible to design very specific drugs that can turn on or off specific groups of neurons that are deregulated in anxiety or depression,” says Lowry.
“Only 13 percent of the species on two people’s hands are the same. Only 17 percent of the species living on one person’s left hand also live on the right one.”—How Microbes Defend and Define Us - NYTimes.com http://nyti.ms/csGMOn
Using farmland to make ethanol is ridiculous. We don’t have enough phosphorus or farmland to go around wasting it on inefficient and messy fuels, and phosphorus shortages are likely to cause a food crisis in the next century even if we don’t waste it making ethanol.
Thorium-based nuclear reactors likely represent the future of energy. Compared to uranium-based nuclear reactors we have more fuel available to run them, they’re more efficient, their fuel is cheaper, and they’re safer, all by several orders of magnitude. Plus the small amount of less harmful waste they do create can’t be used to making weapons. In fact, the only downside which seems to warrant not researching and manufacturing thorium reactors but instead creating more antiquated uranium reactors is that uranium reactors would allow us to continue to replenish our nuclear arsenal.
Fluoridated drinking water makes no sense. There’s a reason we’re asked not to swallow fluoride toothpaste and mouthwash. Fluoride works wonders when applied to the mouth, but it’s harmful to the rest of the body. This is why in the past fluoride had to be disposed of at great cost as a toxic, reactive, heavy metal. While there’s not even a fraction of enough fluoride in a cup of fluoridated drinking water for it to reach toxic levels, fluoride is known to bioaccumulate. What this means is that not all of the fluoride to enter the body actually leaves. Instead some of it stays behind, adding up over time to eventually reach toxic levels. In particular fluoride from drinking water is known to accumulate in the thyroid and skeleton and can cause no small amount of harm over the course of decades.
"You get what you pay for" is bullshit. Price tags have a passing connection to the quality of goods at best. Consumers are biased and uninformed, manufacturers are frequently opaque, deceptive, or corrupt, and legally obliged to be sociopathic in their dealings for the sake of their shareholders, and value itself is relative.
Fascist governments don’t really have redeeming qualities. The phrase “At least Mussolini made the trains run on time” was only used ironically when Mussolini was in power. In reality he only released propaganda saying the trains ran on time. They didn’t.
The balance of ecosystems and course of evolution is frequently determined by parasites. For example deer are able to outcompete moose and caribou largely because nearly all deer in some states carry and spread a brainworm which is nonlethal to deer but lethal to caribou and moose communities. In effect deers are winning the game of evolution not through their own positive qualities but because they’ve inadvertently acquired a bioweapon as a teammate and symbiote, similar to Venom from the Spider-Man comics.
…It’s too early to determine conclusively why U.S. creativity scores are declining. One likely culprit is the number of hours kids now spend in front of the TV and playing videogames rather than engaging in creative activities. Another is the lack of creativity development in our schools. In effect, it’s left to the luck of the draw who becomes creative: there’s no concerted effort to nurture the creativity of all children.
Around the world, though, other countries are making creativity development a national priority. In 2008 British secondary-school curricula—from science to foreign language—was revamped to emphasize idea generation, and pilot programs have begun using Torrance’s test to assess their progress. The European Union designated 2009 as the European Year of Creativity and Innovation, holding conferences on the neuroscience of creativity, financing teacher training, and instituting problem-based learning programs—curricula driven by real-world inquiry—for both children and adults. In China there has been widespread education reform to extinguish the drill-and-kill teaching style. Instead, Chinese schools are also adopting a problem-based learning approach.
Plucker recently toured a number of such schools in Shanghai and Beijing. He was amazed by a boy who, for a class science project, rigged a tracking device for his moped with parts from a cell phone. When faculty of a major Chinese university asked Plucker to identify trends in American education, he described our focus on standardized curriculum, rote memorization, and nationalized testing. “After my answer was translated, they just started laughing out loud,” Plucker says. “They said, ‘You’re racing toward our old model. But we’re racing toward your model, as fast as we can.’ ”