Archive Page 3

Ritalin

I’ve been reading a lot about methylphenidate lately. Commonly known as Ritalin and Adderal, drugs that are supposed to be prescribed for attention deficit disorders and, less commonly, narcolepsy are apparently all the craze for overachieving high school and college students. The statistics are alarming:

  • According to a 1996 Drug Enforcement Agency (DEA) study of three states (Wisconsin, South Carolina, and Indiana), roughly 30-50 percent of adolescents in drug treatment centers reported “non-medical” use of methylphenidate. However, it wasn’t identified as their primary drug of abuse.
  • In the last 10 years, the number of preschoolers taking ADD/ADHD drugs has tripled; the number of school-age children has multiplied by 20. More than 2 million American children are prescribed drugs for ADD/ADHD. Adderall represents about a quarter of the market.
  • Last year, Nature published a commentary which looked into the ethics of such drugs and sparked off a heated debate in a Nature Network forum and among fellow bloggers. More recently, the magazine released the results of an informal survey of over 1,400 readers, which showed that about 20% admitted to using cognitive enhancers for non-medical reasons and a far higher proportion approved of such use.

Ritalin is, in many ways, a time machine. It offers the means to cram a weeks worth of studying into one infinitely productive night. Kickstart My Heart, a well written article for n+1 magazine, is easily the best Ritalin abuse memoir I’ll ever read. If you have ten minutes and enjoy good prose or valuable insights, read the whole thing:

The feeling begins about twenty minutes after you take the pill: a mental tightening, as though someone had refined your scope of vision into a narrow and penetrating line. All peripheral distractions disappear (you would make a very poor hunter or soccer player). There is a slight fluttering of the heart, and gentle, persistent waves of warmth that are not distracting unless it is hot outside. This is how I experienced Adderall; some people have panic attacks and others feel nothing at all.

Any actual amount of time spent under the influence is hard to describe, because time passes very quickly. It’s a euphoric drug, but also an alienating one. If I took a pill with my morning coffee, it would wear off by early evening. All of my work for the coming week would be finished, and I could take an aspirin, shower, and go to bed. Having missed the transition from day to night as well as all three meals, my dreams would be hysterical, but I always woke the next day feeling chipper and accomplished.

Surprisingly, Ritalin’s mechanism of action is poorly understood. We understand what happens physiologically but we’ve no clue how the physiological processes result in focused attention.

Volcow et al. published a recent paper in PLoS reported on by Ed from Not Exactly Rocket Science. Ed explains:

To test this idea, Volkow used a PET-scanner to measure the amount of glucose (sugar) used by the brains of 23 volunteers as they did some mathematical calculations. The volunteers were injected with either methylphenidate or a placebo and asked to solve simple arithmetical problems, whose difficulty had been tailored to their individual abilities. As a control, they were asked to look at, but not respond to, images of scenery.

When faced with the pretty pictures, the volunteers brains behaved in the same way regardless of what they were injected with. It was only when they had to do the more complex mental task that the effects of methylphenidate were revealed. The brains of both groups burned up more glucose but while those that had been shot up with placebo used up 21% extra sugar, those that were drugged with methylphenidate only needed half as much – an extra 11%.

These figures suggest that the drug is indeed focusing the brain’s activity and dramatically reducing its energy demands.[…]

Volkow’s work could help to explain why cognitive enhancers like methylphenidate can hone brain performance in some people and some contexts, but be equally detrimental in others. Sleep-deprived individuals, or those with ADHD, may benefit from a chemical that deploys their brain’s resources in a more efficient way. People whose brains are already working at their best could suffer from being focused any further.

So there it is, Methylphenidate, the stimulant that makes the brain work less.

Alcohol and Epigenetics

A recent article in the Journal of Neuroscience provides insight as to why alcoholics may experience withdrawl anxiety. Neuroscientifically Challenged explains:

Previous research has pointed to the importance of a neuropeptide transmitter called neuropeptide Y (NPY) in managing anxiety, and in modulating alcohol consumption. Low levels of NPY, specifically in the amygdala, have been found in animals that have a preference for alcohol. Additionally, knockout mice who are engineered to lack NPY receptors exhibit an increased proclivity for alcohol.

The aforementioned study explores how those changes occur via epigenetic mechanisms. Epigenetics, literally “on top of” or “in addition to” genetics, studies how genetic packaging affects gene (and subsequently protein) expression.

There are two general avenues of investigation. The first is chromatin remodeling and the second individual gene promoter methylation. These investigators focused on the former.

The complex of DNA and associated nuclear proteins is called chromatin. Chromatin can be densely packed to minimize gene expression or loosely packed to maximize it. Histones, the proteins the DNA wraps around, are methylated when “closed” and acetylated when “open”.

Histone deacetylase inhibitors (HDACs) remove acetyl groups from the histones and lead to a general downregulation in gene expression. The investigators found that alcohol inhibits HDACs and subsequently upregulates NPY gene expression in areas where it has an anxiolytic capacity. Withdrawl, then, upregulated HDACs, downregulated NPY, and caused stress. Administration of a HDAC inhibitor before and during the withdrawl eliminated observable stress.

There are claims that they may have found a novel treatment for alcoholism. I, however, remain skeptical. The anxiolytic effect of the HDAC inhibitor probably has to do with an upregulation of GABA (the primary inhibitory neurotransmitters in the brain) since it is widely reported that HDAC inhibitors have an effect on GABAergic transmission. HDACs are are just too unspecific and, in many ways, carpet bomb gene expression at large. NPY, while certainly a significant part of the picture, may be overshadowed by the HDAC inhibitor induced GABA upregulation.

Nonetheless, it’s a noteworthy article.

Free Will?

Libet’s readiness potential experiments are old hat. In them, Libet measured a spike of characteristic neuronal activity up to 300ms before the decision to push a button. Even though Libet himself thought that free will acts as a veto faculty sometime after the rediness potential his data were (and are still at times) heralded by biological determinists and materialist polemicists as a denunciation of free will.

Regardless of the controversy surrounding Libet’s contribution to the free will debate, his experiment’s notoriety alone begs additional investigation. Nature Neuroscience published an interesting article by a group at the Max Planck Institute for Human Cognitive and Brain Sciences in Germany that elaborates on his studies using fMRI.

There has been a long controversy as to whether subjectively ‘free’ decisions are determined by brain activity ahead of time. We found that the outcome of a decision can be encoded in brain activity of prefrontal and parietal cortex up to 10 s before it enters awareness. This delay presumably reflects the operation of a network of high-level control areas that begin to prepare an upcoming decision long before it enters awareness.

Siong Soon et al’s findings contrast Libet’s in that they pinpoint a different and higher level control area that dictates the occurrence of the readiness potential.

These findings are a good indicator of the existence of unconscious processes that influence decision making; however, they are not a significant addition to the materialist’s bag of tricks. They do not denounce free will. They simply suggest that, as we would’ve anticipated, decision making processes have something to do with cortical neuronal activity.

Libet passed away in late 2007.

Cookie Monster

I laughed really hard when I read this introspection by the Cookie Monster probing what makes him a monster. It makes you wonder what it means to be “abnormal” in the clinical psychology sense.

Enjoy.

(via Mind Hacks)

Natalie Portman

While perusing through MindHacks’ archives I happily stumbled on  an amazing piece of investigative reporting. Turns out Natalie Portman ( <3 ) did some neuroscience research while she was at Harvard.

Click here to see the paper she helped publish.

Happy Friday =).

Video Game Addiction

An editorial in this month’s American Journal of Psychiatry makes an argument for why Internet Addiction should be included in the new DSM.

MindHacks is critical:

Apart from the fact that these and most other supposed criteria make no distinction between using the internet and what the person is using the internet for, it’s easy to see that they don’t describe anything unique to the net.

Rather curiously, the editorial mentions the figure that 86% of people with ‘internet addiction’ have another mental illness. What this suggests is that heavy use of the internet is not the major problem that brings people into treatment.

Firstly, the author posits a diagnosis involving an explicit distinction about what people are using the computer for (not just the internet):

Conceptually, the diagnosis is a compulsive-impulsive spectrum disorder that involves online and/or offline computer usage (1, 2) and consists of at least three subtypes: excessive gaming, sexual preoccupations, and e-mail/text messaging (3).

He’s more concerned about the sheer magnitude of time young people spend on their computers and the negative ramifications thereof.

The average South Korean high school student spends about 23 hours each week gaming (8), another 1.2 million are believed to be at risk for addiction and to require basic counseling.

Furthermore, it’s not like the DSM shouldn’t have any overlap. Comorbidty is rather common. Spending 23 hours a week is obviously abnormal. If the individual feels like they’re addicted and they’re distressed by it I don’t see why we wouldn’t treat it. If they are willing to spend their time and money working out their issues and a mental health professional is willing to improve their quality of life… why not?

Not all disorders are as concrete as schizophrenia or bipolar.  I, for one, think Video Game Addiction is a worthwhile inclusion.

AugCog

I was interested to learn that:

The Pentagon is working on a series of computers that monitor and adapt to a person’s brain:

Augmented Cognition relies on the idea that people have more than one kind of working memory, and more than one kind of attention; there are separate slots in the mind for things written, things heard and things seen. By monitoring how taxed those areas of the brain are, it should be possible to change a computer’s display to compensate. If people are getting too much visual information, send them a text alert. If they are reading too much at once, present some of the data visually — in a chart or map.

They are also working on technology to “tap the firings of the subconscious mind to sort through satellite pictures quickly. Early tests have shown as much as a six-fold increase in the analysts’ efficiency, when the computer and the brain work together.”

(via Clusterflock)