Changes to psychiatrists’ diagnostic ‘bible’ hinted at

PsychCentral reports on the likely changes to appear in the DSM-V, the new version of the psychiatrist’s diagnostic manual, due out in 2012 and discussed in a recent presentation in last week’s American Psychiatric Association annual conference.

The most significant change proposed has to do with the inclusion of dimensional assessments for depression, anxiety, cognitive impairment and reality distortion that span across many major mental disorders. So a clinician might diagnose schizophrenia, but then also rate these four dimensions for the patient to characterize the schizophrenia in a more detailed and descriptive manner.

Despite the PR spin that “no limits” were placed on this revision of the DSM, the reality is that there will be very few significant changes from the existing edition of the DSM-IV. While virtually all disorders will be revised, the revisions will, for the most part, be incremental and small. Why? Because the APA recognizes that you can’t retrain 300,000 mental health professionals (not to mention the 500,000 general physicians) in the field to completely relearn their way of diagnosing common mental disorders such as depression, bipolar disorder, ADHD and schizophrenia. Changes are always incremental and tweak the existing system, nothing more.

The inclusion of dimensional ratings owes much to the role of psychometrics in the assessment of mental illness, but it remains to be seen how extensively this is implemented as it could just be a fancy label for sub-categories of degree (slight, moderate, severe etc) rather than the reliance on statistically sound measurements.

The post also mentions that there may be some moving of the diagnostic furniture with some additions and retractions but no major shakeups.

There’s more coverage on MedPage, but bear in mind that as we’re still three years away from publication so it’s worth bearing in mind that some of the final decisions have still to be made.

Link to PsychCentral post ‘Update: DSM-V Major Changes’.
Link to MedPage coverage.

Russian roulette in the medical literature

Photo by Flickr user bk1bennet. Click for sourceI’ve just discovered there’s a small medical literature on deaths by Russian roulette, where people put one bullet in a revolver, spin the chamber, put the gun to their head and pull the trigger.

A recent article from the The American Journal of Forensic Medicine and Pathology has a 10-year case review covering 24 deaths (wow) from the US state of Kentucky alone and serves as a summary of the research into this fate-tempting and most suicidal of games.

It’s a curious set of studies for which the most reliable finding is that people who die by Russian roulette are mostly young men who were drunk or had taken drugs.

On the more unusual side, one study found a link between participation in Russian roulette and “the types and number of tattoos and body piercing”.

The article also briefly describes a number of previous case reports from the literature, including this one which is remarkable for both mathematical and ultimately tragic reasons:

Playing a variation of traditional Russian roulette with his brother and 2 friends, the victim placed 5 live rounds in the cylinder, leaving one empty chamber, of a .357 Traus revolver. He spun the cylinder, put the gun to his right temple, and pulled the trigger. Postmortem blood toxicology revealed an ethanol level of 0.01% and the presence of diazepam and nordiazepam. The decedent had played Russian roulette on 2 occasions in the previous several weeks, each time placing only one live round in the cylinder.

Link to study on Russian roulette and risk-taking behaviour.
Link to DOI entry for same.

Freestyle Lehrer

Edge has an excellent interview with science writer Jonah Lehrer who riffs on consciousness, the joy of discovery, the importance of the marshmallows in psychology and how he fell in love with science.

It’s interesting because rarely do science writers get the opportunity to give their own opinions on the big questions in neuroscience, despite the fact that, as Lehrer mentions, they have a distinct way of looking at the field as a whole.

Writers have a massive influence on politics, economics, business and the arts, to the point where they are actively courted and coerced by those wanting to control the agenda, but there is much less of a tradition of writers influencing science outside the political sphere.

In fact, it’d be interesting to directly ask science writers for their own theories one day, but in the mean time here’s a rare opportunity to see one ‘in action’ on the big issues.

The questions I’m asking myself right now are on a couple different levels. For a long time there’s been this necessary drive towards reductionism; towards looking at the brain, these three pounds of gelatinous flesh, as nothing but a loop of kinase enzymes. You’re a trillion synaptic connections. Of course, that‚Äôs a necessary foundation for trying to understand the mind and the brain, simply trying to decode the wet stuff.

And that’s essential, and we’ve made astonishing progress thanks to the work of people like Eric Kandel, who has helped outline the chemistry behind memory and all these other fundamental mental processes. Yet now we’re beginning to know enough about the wet stuff, about these three pounds, to see that that’s at best only a partial glance, a glimpse of human nature; that we’re not just these brains in a vat, but these brains that interact with other brains and we are starting to realize that the fundamental approach we’ve taken to the mind and the brain, looking at it as this system of ingredients, chemical ingredients, enzymatic pathways, is actually profoundly limited.

The question now is, how do you then extrapolate it upwards? How do you take this organ, this piece of meat that runs on 10 watts of electricity, and how do you study it in its actual context, which is that it’s not a brain in a vat. It’s a brain interacting with other brains. How do you study things like social networks and human interactions?

Link to Jonah Lehrer interview on Edge.

Encephalon 71 welcomes new diners

The 71st edition of the Encephalon psychology and neuroscience writing carnival has just been served in the welcoming surroundings of the stylish Neuroanthropology blog.

A couple of my favourites include a podcast interview with neuropsychologist Chris Frith from the Brain Science Podcast blog, and a post on the development of early language from Babel’s Dawn.

There plenty more on the menu, so you should find something to suit every taste. Bon appétit!

Link to Encephalon 71.

A hostage to hallucination

Photo by Flickr user Meredith Farmer. Click for sourceI’ve just found a morbidly fascinating 1984 study on hallucinations in hostages and kidnap victims.

The paper is from the Journal of Nervous and Mental Disease and contains case studies of people who have been held captive by terrorists, kidnappers, rapists, robbers, enemy troops and, er… UFOs.

The reasoning behind including two ‘alien abductees’ was to compare hallucinations in verified versus unverified hostage situations. Cases of people who were hostages but did not hallucinate are also included.

The study found that one in four hostages had intense hallucinations, and these were invariably people who were in life-threatening situations. Isolation, visual deprivation, physical restraint, violence and death threats also seemed to contribute to the chance of having a hallucinatory experience.

Case 14

A 23-year-old member of a street gang was taken hostage by a rival gang. He was kept in a warehouse, blindfolded and tied to a chair, for 32 hours. He was severely beaten and forced to record ransom demands on a tape recorder. During captivity he became dissociated – “even when they were hitting on me I just tripped out, got out of my body… it was like I was high on Sherms (phencyclidine).” At one point he felt detached from his body and “floated” to the ceiling where he observed himself being beaten and burned with cigarettes but denied having any pain. He saw colorful geometric patterns in the air and flashes of past memories “like a dream, only I kept seeing devils and cops and monsters… nightmares I guess”. Eventually he was released when his gang paid the ransom.

Some of the case studies are a little disturbing, but it’s worth reading the paper in full if you can, or at least from the beginning of the case studies, as it’s a rarely discussed but remarkably striking aspect of human experience.

Link to article on ‘Hostage Hallucinations’.
Link to PubMed entry for same.

On the information alarmageddon

New York Magazine has an article arguing that the concerns about digital technology drastically affecting our minds are just hype. I really wanted to like it but it’s just another poorly researched piece on the psychology of digital technology.

Research has shown that distraction can improve exactly the sorts of skills that the digital doomsayers say will be broken by the high-tech world, but I’ve never seen it mentioned in any of the recent high-profile articles on the predicted digital meltdown.

In fact, there is a fairly sizeable scientific literature on how interruption affects the ability to complete a task, and instant messaging has been specifically studied.

But despite getting lots of opinions from everyone from attention researcher David Meyer to lifehacker Merlin Mann only one single ‘study’ on the distracting effect of technology is mentioned in the New York Magazine article: “people who frequently check their email has tested less intelligent than people who are actually high on marijuana”.

This is quite amazing because not only was the ‘study’ in question not an actual scientific study, it was PR stunt for Hewlett Packard, this isn’t even an accurate description of it (users were interrupted with email during an IQ test and scored worse, big surprise).

The issue actually breaks down into two parts, one is a scientific question: what is the psychological effect of distraction? and the other, a cultural one: have we become a society where high levels of distraction are more acceptable?

As I mentioned, the first question has been very well researched and the general conclusion is that distraction reduces our ability to complete tasks. Essentially, it’s saying that distraction is distracting, which is hardly headline news.

But it also turns out that distraction is most disruptive to stimulus based search tasks, when we are flicking our attention around scanning for bits of information. Perhaps unsurprisingly, when we’re on alert for new and different things, something salient like an instant message grabs our attention and knocks us off course.

More thoughtful tasks involving processing meaning are the least affected. This is interesting because most of the digital doomsayers suggest it is exactly this sort of deep thought that being affected by communication technology.

The other line of argument is that all this distraction makes us less creative because creativity needs focus to flourish.

Although not as well studied, it seems this is unlikely. While we assume that distraction reduces creativity, but lab studies tend to show the reverse.

Distraction has also been found to improve decision making, especially for complex fuzzy decisions – again exactly the sort that the doomsayers say will most be at peril.

These studies find that too much concentration reduces our creative thinking because we’re stuck in one mind-set, deliberately filtering out what we’ve already decided is irrelevant, thereby already discarding counter-intuitive ideas (actually this is something the article does touch on). We can speculate that this may be why a preliminary study found that amphetamine-based concentration drug Adderall reduced creativity.

The cultural issue is perhaps more important, but on an individual level is more easily addressed.

You have control over the technology of distraction. If you can’t concentrate, switch it off. It it is your job to be distracted and it is affecting other essential parts of your role, that is something to take up with your employers.

It’s no different than if you’re being distracted by the sound of traffic and can’t do your job. Maybe you need an office away from the street? If you or your employers can’t do anything about it, maybe that’s just one of the downsides of the job.

What research hasn’t yet shown is that digital technology is having a significant negative influence on our minds or brains. In some cases, it’s showing the reverse.

History has taught us that we worry about widespread new technology and this is usually expressed in society in terms of its negative impact on our minds and social relationships.

If you’re really concerned about cognitive abilities, look after your cardiovascular health (eat well and exercise), cherish your relationships, stay mentally active and experience diverse and interesting things. All of which have been shown to maintain mental function, especially as we age.

Technology has an impact on the mind but it’s a drop in the ocean compared to the influence of your health and your relationships.

I’m constantly surprised that the impact of technology is clearly of such widespread interest to merit headline grabbing articles in international publications, but apparently not interesting enough that journalists will actually use the internet to find the research.

It’s like writing a travel guide without ever visiting the country. I’m just guessing the editors have yet to catch on to the scam.

Link to NYMag article ‘In Defense of Distraction’.

Can’t put the thought genie back into the bottle

Photo by Flickr user kaneda99. Click for sourcePsyBlog has an excellent piece on the counter-intuitive psychology of thought suppression – the deliberate attempt to not think of something that almost invariably backfires.

The article is both fascinating from a scientific point-of-view but also important as a personal mental health resource if you’re one of the many people who intuitively think that the best way of dealing with ‘bad’ thoughts is to try and push them out of the mind.

What psychology research has shown us is that not trying to think of something makes us think of it more frequently (the “don’t think of a pink elephant” phenomenon), and that this counter-productive effect is enhanced for emotion-heavy thoughts and in people with mental illnesses where intrusive thoughts are a problem.

Psychologists often use the metaphor of noisy trains passing through the station. Thought suppression is like standing in the middle of the tracks trying to push the train back. You’re just going to get run over. Instead, people are encouraged to just wait on the platform, observe the train of thought and wait for it to pass.

The ability to act as a ‘detached observer’ to the mind’s distressing thoughts is a useful cognitive skill and one that is cultivated by mindfulness mediation, something that has increasing evidence as a useful treatment for mental health problems.

There’s lots of good research on thought suppression, much of which is covered in PsyBlog article, but this study struck me as particularly inventive:

Wegner and Gold (1995) examined emotional suppression by delving into people’s romantic pasts using a neat comparison between ‘hot flames’ and ‘cold flames’. A ‘hot flame’ is a previous partner who still fires the imagination, while a ‘cold flame’ is a previous partner for whom the thrill is gone. In theory the ‘hot flame’ should produce more intrusive thoughts so people should have more practice suppressing them. Meanwhile because the cold flame doesn’t produce intrusive thoughts, people should have less practice suppressing them.

The results revealed exactly the expected pattern: people found it harder to to suppress thoughts about cold flames presumably because they had less practice.

Link to PsyBlog on ‘Why Thought Suppression is Counter-Productive’.

2009-05-22 Spike activity

Quick links from the past week in mind and brain news:

Neuroanthropology has a great article on identity formation and internet booze show-offs. A neat bit of online anthropology.

Psychopathic traits in children associated with severe deficits in emotional empathy across all ages for males, but not females, finds new study published in Journal of Child Psychology and Psychiatry.

Scientific American has a short but interesting piece on how hand movements during discussion may aid cognition. I would do the ‘sounds a bit handy wavy’ joke but I suspect I’ve been beaten to the punch.

Actually, I’d just like to apologise for the pun in the line above while I have the chance.

Science Daily reports that intelligence and physical attractiveness are both related to income. Which explains a lot about my current situation, actually.

Doctor saves young lad’s life by drilling into his brain with a power drill, reports the Aussie News site. The embedded video seems to have been made by The Onion though.

PsyBlog rounds up its recent excellent series on functions and dysfunctions of attention in one handy place.

Psychiatrist bemoans the ignorance about the benefits of lithium treatment among junior doctors in The New York Times.

Science News reports another in a long line of studies suggesting the benefits of meditation. In this case, that it’s linked to increased grey matter in key emotion areas.

Lacan’s florid and Byzantine model of the unconscious is covered in two posts by Somatosphere.

The Harvard Gazette reports on ‘super-recognisers‘, people with exceptionally good face recognition abilities. See this 1999 study for a report of a super-over-recogniser.

Musicians have better memory not just for music, but words and pictures too, according to a study expertly covered by Cognitive Daily.

The Economist looks at a recent study that finds that living abroad can increase creativity.

Risk of violence in schizophrenia almost entirely explained by illicit drug use, finds new study reported on by PhysOrg.

Science News reports that people who have a higher alcohol tolerance are more likely to become alcoholic.

The summer fundraiser for Phil Dawdy, the world’s only publicly funded psychiatry-dedicated investigative reporter kicks off on Furious Seasons.

The New York Times has an excellent piece on the ‘super memory club‘, people who live beyond the age of 90 with sharp-as-a-razor cognitive abilities.

A study investigates the typical psychological traits of people who believe in conspiracy theories, which is covered by Science News.

Science Daily reports on a freaky ass robot intended to improve social skills, presumably built by researchers who have spent too much time in the lab.

The excellent Situationst blog has a must-read piece on the controversy over implicit bias, one of the most heavily researched aspects of our unconscious.

To the bunkers! Time magazine reports that replicant Ray Kurzweil is still at large.

On a wing and a prayer

Photo by Flickr user Rickydavid. Click for sourceNPR has an interesting audio series on brain function, spiritual experience and the growing field of neurotheology. It’s takes a fairly broad brush approach and has audio, video, an interactive thingy, and plenty of supporting material.

You might get slightly annoyed at some of the section titles (‘The God Chemical’, ‘The God Spot’) but there are some great little audio vignettes in there where people describe their spiritual experiences, whether they’ve been caused by prayer or even psilocybin – the main active ingredient in magic mushrooms.

The project borders on the edge of being a bit hokey at times but it saved by the commentary and interviews with neuroscientists working in the area.

There’s also a good article in June’s Scientific American entitled ‘Why People Believe Invisible Agents Control the World’ which looks at the origin of belief in angels, demons, spirits and the like.

Link to NPR interactive brain / god thingy.
Link to ‘Why People Believe Invisible Agents Control the World’.

Bolt from the blue triggers bizzare hallucinations

I just found this amazing case study of a female mountaineer who was struck by lighting while climbing the Latemar Peak in the Alps and subsequently experienced a series of unusual symptoms.

She was taken off the mountain by helicopter and was so agitated in hospital she had to be put under for three days. On wakening she was having some remarkably bizarre hallucinations.

On 3 September 2004, a 23-year-old healthy woman was hit by a “bolt from the blue” while climbing on a ridge at 2750 m shortly before reaching the Latemar Peak in the Alps from a southern direction. The accompanying climber was about 50 m from the casualty, and reported that at the time of the incident (about 15:00 Central European Time (CET)), the sky was clear and sunny. He heard cracking thunder and was thrown to the ground by a massive shock wave.

The patient was also thrown to the ground, lost consciousness for a few seconds and was confused afterwards. She had no vision, dazzled by a bright light. On arrival of the air rescue team, her Glasgow Coma Scale was 9. She was hospitalised and because of extreme agitation, set to a drug-induced coma for 3 days. The initial CT scan showed bilateral occipital oedema, but no intracerebral or subarachnoid haemorrhages or skull fractures…

In the evening, still awake and 6 h after extubation, strange phenomena occurred. These exclusively visual sensations consisted of unknown people, animals and objects acting in different scenes, like a movie. None of the persons or scenes was familiar to her and she was severely frightened by their occurrence. For example, an old lady was sitting on a ribbed radiator, then becoming thinner and thinner, and finally vanishing through the slots of the radiator.

Later, on her left side a cowboy riding on a horse came from the distance. As he approached her, he tried to shoot her, making her feel defenceless because she could not move or shout for help. In another scene, two male doctors, one fair and one dark haired, and a woman, all with strange metal glasses and unnatural brownish-red faces, were tanning in front of a sunbed, then having sexual intercourse and afterwards trying to draw blood from her.

These formed hallucinations, partially with delusional character, were in the whole visual field and constantly present for approximately 20 h. At the time of appearance, the patient was not sure whether they were real or unreal, but did not report them for fear that she might be considered insane.

Link to PubMed entry for case study.

Tall people have slower nerves, sensory lag

Frontal Cortex has alerted me to an interesting NPR radio segment on the fact that taller people have longer nerves and so will have slight sensory lag in comparison to shorter people.

It prompted me to look up some of the research in the area and I found an eye-opening study looking at a range of factors that can effect nerve conduction.

The researchers found that, after controlling for sex, age and temperature (it turns out your nerves are quicker when you’re warm), there was a 0.27 m/s decrease in the conduction speed of one of the leg nerves (the sural nerve) for each additional centimetre in height.

This is interesting because it is not only a reduction in time because the same speed signal is travelling a longer distance, but it actually seems that nerve signals travel more slower through longer nerves as well, owing to the fact the nerves get thinner the longer they are.

The radio segment suggests that taller people don’t experience the world as any different, because our brains try to make everything seem ‘in sync’.

In fact, this is a problem for everyone, no matter how tall we are, because we know we can update our actions quicker than the sensory signals can reach the brain.

In one of the most popular theories that attempt to explain this it it thought that we have an internal simulation of our actions that we can use to make fast decisions which is updated as and when sensory information arrives.

However, I tried to find some studies on whether taller people actually have slower reaction times, but I couldn’t find any, so let me know if you do.

Link to NPR ‘The Secret Advantage Of Being Short’.
Link to study on nerve conduction factors.
Link to DOI entry for same.

I think I’m losing my walnuts

This page on herbal treatments for amnesia made me laugh out loud:

Amnesia is usually caused by some traumatic event, like an accident or a blow to the head. It may also be caused by taking certain sedatives. Some cases are caused by disease like Alzheimer’s, which directly affects the brain, or because of poor brain circulation. A poor memory may also be exacerbated by a lack of stimulation. Some cases of amnesia are also psychologically based, caused by neurosis or anxiety…

Herbal Treatments

Rosemary ‚Äì taking rosemary tea may help improve the memory as well as support the entire body’s systems. This tea can be taken as needed for forgetfulness…

Walnut ‚Äì this proven memory booster is a good natural remedy for loss of memory. Eating walnuts on a regular basis will help recover memories…

Black pepper ‚Äì mix five finely ground black pepper seeds with a teaspoon of honey and take it twice per day to help the memory and to improve amnesia…

Rosemary, Walnut and Black Pepper? There’s probably some vegan restaurant in San Francisco that’s cured hundreds by now.

Link to herbal cures for amnesia page.

Send a signal to table three please

Photo by Flickr user Rob Lee. Click for sourceThere’s a brief but interesting article in The New York Times about how we use consumer goods to ‘send signals’ to other people. It illustrates this with a fantastic example and then misses the point. Luckily another recent study on unconscious influences on doctors hits the punchline.

The idea that each product has a meaning and that we use our purchases to construct an identity from the ‘language of brands’ is not completely new, indeed, we’ve covered it before on Mind Hacks, but there’s a nice illustration of this in the most recent NYT article:

Most of us will insist there are other reasons for going to Harvard or buying a BMW or an iPhone — and there are, of course. The education and the products can yield many kinds of rewards. But Dr. Miller says that much of the pleasure we derive from products stems from the unconscious instinct that they will either enhance or signal our fitness by demonstrating intelligence or some of the Big Five personality traits: openness, conscientiousness, agreeableness, stability and extraversion.

In a series of experiments [pdf], Dr. Miller and other researchers found that people were more likely to expend money and effort on products and activities if they were first primed with photographs of the opposite sex or stories about dating.

After this priming, men were more willing to splurge on designer sunglasses, expensive watches and European vacations. Women became more willing to do volunteer work and perform other acts of conspicuous charity — a signal of high conscientiousness and agreeableness, like demonstrating your concern for third world farmers by spending extra for Starbucks’s “fair trade” coffee.

Unfortunately, the article then goes on to say that we may do these things because we try and send signals to others but that people don’t notice because who can really remember whether the guy we met the other day was wearing a designer shirt or not?

The reason this misses the point is that the influence can be both dramatic and entirely conscious as nicely demonstrated by a recent study on doctors that was also reported in the NYT and, ironically, seems to have done unnoticed.

Researchers asked medical students about their attitudes to two blockbuster anticholesterol drugs: Lipitor and it’s competitor, Zocor.

The students were tested in two groups, but in one the researchers incidentally used Lipitor branded pens, clipboards and the like – the typical sort of banal junk that drug companies leave scattered around a typical doctor’s office.

The researchers then tested unconscious associations using the IAT and found that students in the condition where researchers used the branded promotional material had much stronger positive associations with Lipitor.

Interestingly, the students reported no explicit preference for the drug, suggesting that the effect of the branding slipped in under the radar of consciousness. The message got through despite it being not being held as a conscious memory.

Social psychology has taught us that we are more much complex than we can understand at any one moment, but many of those messages still get through.

Link to NYT piece on consumer signalling.
Link to NYT piece on small gifts influencing doctors.
Link to full-text of study.

Medical fetish lacks passion

Dr Petra has alerted me to an excellent article in The Boston Globe about a new campaign to get the ‘doctor out of the bedroom’ and de-medicalise sex and sexual problems.

The piece is particularly focused on how sex is being increasingly portrayed in terms of physiology, bodily mechanics and disorders while ignoring the role of psychology and relationships.

This is particularly pertinent at the moment, owing to millions being pumped into the so-far fruitless search for a ‘female Viagra’ intended to increase sexual desire in women.

Eager to replicate the outsized profits that erectile dysfunction drugs have brought, several pharmaceutical firms are in hot pursuit of a women’s version. Because female sexual desire is far less straightforward than men’s, success has been thus far elusive, but there are several candidates in the pipeline. Whether any of them will work well enough – and without significant adverse health effects – to gain FDA approval remains to be seen. (In Europe, a testosterone patch to boost sex drive in post-menopausal women has been approved, but its efficacy is debated.)

For critics, the problem is not whether a women’s Viagra will work, but what happens if it does. They argue that the very concept of “female sexual dysfunction,” the condition that such drugs would be targeting, is not an actual medical condition so much as a creation of the pharmaceutical industry. While surveys show that 20 to 40 percent of women describe themselves as having a lack of interest in sex (the higher figures tend to come from studies funded by pharmaceutical companies), only about a quarter of those women describe that as a problem. It’s hard to call something a disorder or a dysfunction, some sex researchers argue, if the people who experience it don’t tend to see it that way.

The piece looks at a group of sex researchers and clinicians who are arguing for a ‘New View’ that doesn’t think of all sexual difficulties as medical disorders and focuses upon the important role of psychology in sexual arousal, motivation and exploration.

As Petra notes, it’s unusual to see a mainstream article straying from the now well-worn path so get it while it’s, er, hot.

Link to Boston Globe article ‘The New Romantics’.
Link to Dr Petra on the piece.

Numbers up for dopamine myth

Photo by Flickr user the underlord. Click for sourceI’ve just read an elegant study on the neuroscience of gambling that wonderfully illustrates why the dopamine equals pleasure myth, so often thrown around by the media, is too tired to be useful.

I have seen countless news reports that claim that some activity or other causes dopamine to be released; that dopamine is the ‘pleasure chemical’; and that it’s also released by ‘drugs’, ‘sex’, ‘gambling’ and ‘chocolate’ (a quartet I have named the four dopamen of the neurocalypse).

Normally, this breathless attempt to make something sound sexy is followed by a slightly sinister bit where they say that this dopamine activity is also likely to make it ‘addictive’.

Dopamine is involved in drug addiction, but the over-extended clich√© is drivel, not least because the dopamine neurons start firing in the nucleus accumbens when any reward is expected. Whether it be heroin, a glass of water when you’re thirsty, or your favourite book on calculus – if that’s what floats your boat.

And herein lies the subtlety. Our best evidence tells us that while the dopamine system has many functions, it’s not really a reward system – it’s most likely a reward expectancy system of some kind. Theories of exactly what form this takes differ in the details, but it certainly seems to be active when we’re expecting a reward, whether it actually turns up or not.

The study on gambling, led by neuroscientist Luke Clark, demonstrates that this is true even when the actual experience is unpleasant.

The research team looked at the activity differences in the dopamine-rich mesolimbic system in a gambling task – comparing wins, misses and near-misses. Near-misses were where the reels on a slot machine just missed the payout.

It turns out that near-misses activate almost exactly the same dopamine circuits as actual wins – but here’s the punchline – they were subjectively experienced as the most unpleasant outcome, even worse than total misses.

In other words, the dopamine system was firing like a rocket display but the experience was awful.

Interestingly, although near-misses were experienced as aversive they increased the desire to play the game but only when the person had some perception of control, by choosing what the ‘lucky’ picture would be.

Of course, like choosing ‘heads or tails’, it’s only an illusion of control because the outcome is random anyway.

But because of reward expectancy the dopamine system is most active when we think we can control the outcome and modify our strategy next time, even if that sense of control is completely false.

Link to full-text of study on near-misses and dopamine.
Link to good coverage of study from Quirks and Quarks.