Category: Medical anthropology

Rats’ visual systems made plastic by anti-depressants

Blogging on Peer-Reviewed ResearchMy mind raced for potential titles to a post when I read the recent report from Science, ‘The Antidepressant Fluoxetine Restores Plasticity in the Adult Visual Cortex,’ by a team headed by José Fernando Maya Vetencourt (abstract), but I’ve opted to be demure, rather than go with some of my other options (like ‘Anti-depressants the “Cocoon” pool for brain?’ or something similarly outrageous).

The research team investigated wither fluoxetine, a selective serotonin reuptake inhibitor (SSRI), could restore plasticity in the visual system of adult rats. They chose fluoxetine because long-term regimens of the drug promote neurogenesis and synaptogenesis in the hippocampus and increased activity of neurotrophin brain-derived neurotrophic factor (BDNF) and its primary receptor, TrkB (close paraphrase to the original article). These effects have been shown essential to the drug’s effect; block one of these processes, and the anti-depressant doesn’t work nearly as well. In order to test plasticity, the team studied how rats responded to monocular deprivation — covering one eye — both the initial shift in ocular dominance and then the recovery of visual function after long-term monocular deprivation. In general, the fluoxetine-treated rats responded in exaggerated fashion to both conditions, suggesting that plasticity was greater with long-term administration of the drug. From the abstract:

We found that chronic administration of fluoxetine reinstates ocular dominance plasticity in adulthood and promotes the recovery of visual functions in adult amblyopic animals, as tested electrophysiologically and behaviorally. These effects were accompanied by reduced intracortical inhibition and increased expression of brain-derived neurotrophic factor in the visual cortex. Cortical administration of diazepam prevented the effects induced by fluoxetine, indicating that the reduction of intracortical inhibition promotes visual cortical plasticity in the adult. Our results suggest a potential clinical application for fluoxetine in amblyopia as well as new mechanisms for the therapeutic effects of antidepressants and for the pathophysiology of mood disorders.

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Antidepressants suppress identity?

Another interesting one from The New York Times, Who Are We? Coming of Age on Antidepressants, by Dr. Richard A. Friedman; I found this one really well done, asking more questions than it answers, but thought-provoking.

The introduction to the article lays out the central existential question posed by long-term treatment with anti-depressants, especially for patients who started on their regimens when very young:

“I’ve grown up on medication,” my patient Julie told me recently. “I don’t have a sense of who I really am without it.”
At 31, she had been on one antidepressant or another nearly continuously since she was 14. There was little question that she had very serious depression and had survived several suicide attempts. In fact, she credited the medication with saving her life.
But now she was raising an equally fundamental question: how the drugs might have affected her psychological development and core identity.

As Friedman points out, the medical testing for these pharmaceuticals doesn’t include long-term research anywhere close to the lengths of time that people are actually spending on the drugs: the longest maintenance study — done on Effexor — lasted two years.

But the more subtle issues that Friedman raises, as far as I’m concerned, are the questions of identity that are clouded by long-term anti-depressant use. He discusses one woman who was concerned about her ‘low sex drive’ and pressure from her boyfriend to have sex after eight years on libido-reducing Zoloft: ‘She had understandably mistaken the side effect of the drug for her “normal” sexual desire and was shocked when I explained it: “And I thought it was just me!”’ I can’t tell from the way Friedman writes this how he feels about the idea that an individual has a ‘normal’ sex drive, something that might exist ‘prior to’ or ‘independent of’ any outside influences, whether that influence be an anti-depressant or a particular life event or the effects of interpersonal dynamics with a partner.

The idea that the ‘anti-depressed’ state might become ‘normal,’ both in the medical sense that intervention seeks to create this state and in the sense that a patient spends so much time in the drug-influenced state that it becomes a kind of reference, suggests yet another way that cultural expectations might become biological ‘nature.’

Moerman’s Placebo

I have been wanting to write a post about the placebo effect for some time, after finding a wonderful YouTube video about getting drunk without being drunk. And then today I saw a very different “placebo effect” that also drives home Dan Moerman’s point when he says that the placebo effect is better thought of as “the meaning response.” (Moerman is an anthropologist, of course.)

The video, How to Get Drunk Without Drinking, shows Derren Brown demonstrating “a method I used at university which allows people to recreate any drug state, adrenaline, alcohol, you name it, without actually taking the drug.” (If it doesn’t play, you can go directly to the YouTube version.) What is so striking about the video is Brown’s use of imagination, embodiment, practice, suggestion, and memory to accomplish the effect, and the ability of the brain to then switch between such different states so quickly. It’s also quite funny!

The other piece, The Cure by Sarah Manguso, is adapted from her forthcoming memoir The Two Kinds of Decay. Manguso writes of being twenty-one, her life in danger from an auto-immune disease, and her desire to make love to someone. Her own antibodies were attacking her body, as she wryly notes, “trying to destroy my nervous system — a misperception that caused me a lot of trouble.” She returned to college with a huge tube sticking out of her chest, a necessary part of the regular blood treatments she needed.

“My blood was removed and cleaned and put back more than 50 times. After that, my hematologist tried another treatment: massive gamma-globulin infusions. The second infusion kept me going for three months, and it was decided I wouldn’t have to have my plasma replaced again. My neurologist said I’d turned a corner, so after 11 1/2 months, my central line was pulled.”

“I believed, though, that I would stop secreting antibodies only after I had sexual intercourse. And though I looked worse than I ever had in my life, thanks to the steroids — I was fat and swollen, covered in acne, and had a gruesomely round face — I thought my legendarily promiscuous musician friend might still be interested.”

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Brain doping poll results in

According to Nature, 20% of scientists in an informal survey admitted to using ‘cognitive enhancing’ drugs: Poll results: look who’s doping. Ironically, the original survey was triggered by an April Fool’s prank played on the scientific community. My initial thought was, Do they count caffeine? Of course, they didn’t. If they did, numbers would obviously be different.

We asked specifically about three drugs: methylphenidate (Ritalin), a stimulant normally used to treat attention-deficit hyperactivity disorder but well-known on college campuses as a ‘study aid’; modafinil (Provigil), prescribed to treat sleep disorders but also used off-label to combat general fatigue or overcome jet lag; and beta blockers, drugs prescribed for cardiac arrhythmia that also have an anti-anxiety effect.

Check out the Nature site for a more complete discussion, but the conclusion is worth repeating:

The most popular of the drugs used by respondents to Nature’s poll seem to have fairly mild neuroenhancing effects, says Chatterjee, who calls the massive media interest in these drugs “neurogossip”. Nevertheless, the numbers suggest a significant amount of drug-taking among academics. As Eisen’s April Fool’s prank spread from blog to blog, it was hard to tell who was in on the joke and who was taking the announcement at face value. Although tricking people was a goal, Eisen had been aiming for something so ridiculous that most would chuckle. Instead, he worries that he might have hit a nerve: “I think it did make it less funny because it is actually too real.”

The initial discussion that led to the poll was referenced by Daniel a while back in a great piece, Brain Enhancement: Beyond Either/Or, that explored this topic in greater detail. If you haven’t checked it out, you should. Daniel talks about the ‘unintended consequences’ that almost always accompany drug use. I don’t have too much to add to that except that, with what we know about neuroplasticity, this should not surprise us at all. The brain and nervous system tend to adapt to any changes in the overall environment they inhabit: the tasks they do, the condition of the environment (which is both inside and outside of the body), any other chemicals introduced into the equation.
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Wednesday Round Up #6

Gaming

Sqrl, Link Between Online Gaming and Violence Killed Off
“People who play violent games online actually feel more relaxed and less angry after they have played”

GameSpot News, Study: Gamers Show Autistic Traits
“the closer gamers were to being addicted to their hobby, the more likely they were to display “negative personality traits.”

Jackie Burrell, Game on Too Long: A Fine Line Separates Addiction, Fun
Relaxed or autistic?! A more balanced consideration of how much is too much

GameSpot News, Video Game Addiction a Mental Disorder?
The comments by gamers—the debate among themselves—provide plenty of insight into the cultural and health issues at stake

Vaughan Bell, Internet Addiction Nonsense Hits the AJP
A critical take on attempts to define internet addiction as a mental illness

Science Daily, Occupational Therapists Use Wii for Parkinson’s Study
The interactive Wii makes for functional fun

Health

Rense Nieuwenhuis, Disentangling the SES-Health Correlation
Poor health and lower class. Going beyond the chicken-or-the-egg to consider pathways

Eric Brunner, Biology and Health Inequality
Online PLOS Biology article: The translation of social differences into biological differences

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Autoimmune epidemic

I’m afraid I don’t have much interesting to say about this link, but I just can’t scrape my jaw off the floor. There’s a story on Alternet about the incidence of autoimmune disorders, The Autoimmune Epidemic: Bodies Gone Haywire in a World out of Balance. I’m simply floored by some of the accounts, the numbers, and the whole phenomenon. I wish I had something to add, but I thought the least I could do was point out the story to some of our readers.

The autoimmune system is of special interest to those of us concerned about how environmental factors affect the development of organisms, including humans, because it is one of the clear cases of a system that gets substantial input from the environment to accomplish basic functions. We also find that it offers all sorts of interesting examples of non-genetic forms of heredity, including influences in utero and the widely-recognized importance of breast feeding for shaping the immune system. Less widely understood are the effects of changing environment on immune system functions in things like allergies.

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