No, this isn’t just a cheap excuse to display a picture of Pamela Anderson.

I just received this from a regular reader:

“Dear Dr Petty,

Have you seen this article Times Online?

“WHEN men meet fair-haired women they really do have a “blonde moment”. Scientists have found that their mental performance drops, apparently because they believe they are dealing with someone less intelligent.

Researchers discovered what might be called the “bimbo delusion” by studying men’s ability to complete general knowledge tests after exposure to different women. The academics found that men’s scores fell after they were shown pictures of blondes.

Further analysis convinced the team that, rather than simply being distracted by the flaxen hair, those who performed poorly had been unconsciously driven by social stereotypes to “think blonde”.

“This proves that people confronted with stereotypes generally behave in line with them,” said Thierry Meyer, joint author of the study and professor of social psychology at the University of Paris X-Nanterre. “In this case blondes have the potential to make people act in a dumber way, because they mimic the unconscious stereotype of the dumb blonde.”

Do you have any comment to make about the research??”

The answer is that I have seen this article all over the Internet, with all kinds of sage comments.

The trouble is that I have not yet been able to read and critique the research. As far as I know, neither the hard copy nor electronic versions are available yet, so I cannot evaluate the report.

This highlights one of the problems of the Internet: news travels across it like the wind, yet a lot of material is passed on without analysis. So the story is fun to read, but until we can see and analyze the data, we cannot comment.

As soon as I get a copy I shall see if I have anything to add to the firestorm of commentary!

I just had a very good question after I published my list of Twelve Tips to Reduce Your Risk of Colorectal Cancer.

Dear Dr. Petty,

“That’s a great list, but I am wondering why you haven’t included aspirin or other non-steroidal anti-inflammatory drugs (NSAIDs)? I thought that they had been shown to reduce the risk of colon cancer.”

This is an excellent question, and I deliberately omitted mention of anti-inflammatories because the research suggests that they may cause more harm than good.

There is a report in today’s edition of the Annals of Internal Medicine from the United States Preventive Services Task Force, a highly regarded and independent panel of experts in primary care and prevention, that confirms that screening for colorectal cancer is still important and everyone over 50 should have it. But they urge caution on taking preventive drugs, saying that on balance the health risks of aspirin outweigh the benefits when it comes to preventing colon cancer. This advice holds even for those people with a family history of the disease, as long as they have only an average risk of colon cancer. (20 per cent of people who get colorectal cancer also have a close relative with the disease, with proportionally more cases among African Americans than other races.)

They found good evidence that high doses of aspirin (i.e. 300 mg a day or more) and possibly ibuprofen protect against colorectal cancer but this comes with increased risk of intestinal bleeding, stroke and kidney failure.

In low doses - under 100 mg a day - the Task Force says that good evidence supports the notion that aspirin protects against heart disease. However, at this dosage it will have no preventive effect on colorectal cancer.

The US Preventive Services Task Force regularly reviews the available research evidence and issues advice based on what they regard the strength of the evidence to be. They use a grades to help guide practice. For example a grade A recommendation is equal to "strongly recommends", while a B is just "recommends", and C is "no recommendation for or against".

In this case the Task Force has issued a grade D "recommends against" to the routine use of aspirin and NSAIDs to prevent colorectal cancer.

So for now I recommend following the Twelve Tips that I published yesterday.

I’ve just received an intriguing article from an individual who’s really been through the mill with an array of psychiatric problems going back to childhood.

The last diagnosis that he attracted was posttraumatic stress disorder (PTSD), and he seems to have cured himself by a combination of omega-3 fatty acids and learning to play the banjo left-handed.

This may sound like a bit of an odd claim, but although the writer did not realize it, there is actually some solid science behind his observation.

For years now we have known that if someone is paralyzed down one side after a stroke, binding the good arm or leg leads to rapid reorganization in the cerebral cortex, as a result of which the paralyzed arm or leg may begin to regain function.

One of the most potent ways to improve the functioning of regions of the brain is to try doing things with the opposite hand: if your are right-handed, brushing your teeth or writing with your left hand or using your knife and fork the other way round can all be very illuminating, and can help train your brain. A common tactic in couple’s therapy is to get people to change some habits, like switching the sides of the bed on which a couple sleeps.

The hippocampus of the brain is involved in many functions, but key amongst them is the laying down of short-term memories. People with several stress-related psychiatric disorders, including PTSD, borderline personality disorder with early abuse, depression with early abuse, alcoholism and dissociative identity disorder all have smaller hippocampi, presumably because this part of the brain is exquisitely sensitive to cortisol: high levels can damage and destroy hippocampal cells. Antidepressant medications and some types of cognitive training are thought to lead to the growth of new cells in the hippocampus. It is also possible that having a small hippocampus may predispose someone to the development of PTSD. There is also some evidence that mixed lateral preferences and parental left-handedness may all predispose someone to the development of PTSD.

In PTSD, the left hippocampus and two other brain regions: the left anterior cingulate cortex and both sides of the insula are all smaller than normal. Regions of this small left hippocampus associated with episodic and autobiographical memory is activated by stimuli that wouldn’t have much effect in people without the problem. Some researchers have also found that if the right hippocampus is smaller and more active, it correlates with the severity of PTSD symptoms.

Adults with PTSD have a higher incidence of mixed laterality with respect to handedness than the rest of the population. This has recently also been found in children: there is a positive correlation between PTSD symptom severity and mixed laterality. This strongly suggests that neurological abnormalities may be related to the severity of symptoms in PTSD.

In PTSD, the right amygdala, a region involved in fear and rapid emotional learning and processing, is smaller than the left. In healthy volunteers it’s the same on both sides.

When people with PTSD recall the traumatic event, especially if it involved assault, they over-activate the right hemisphere of the brain. It is not just cerebral blood flow: recent experimental work has shown that PTSD may be associated with a functional asymmetry of the brain, which favors the right hemisphere.

There are actually a number of therapeutic techniques that involve trying to switch the way in which the hemispheres interact. EMDR (which the writer had tried) is one. It is also amongst the techniques developed by Paul Dennison to aid learning.

I also wonder whether the writer has accidentally happened upon a method for treating psychological reversal.

I do wish the writer well, and I also hope that some of my colleagues in research might be interested in exploring some of these training techniques in PTSD.

Following my recent article about mystical experiences, I had a charming note which included this question:

"Could you kindly give a reference or link to the above quote from Ramana Maharshi?"

This was my response:

"I am traveling at the moment, so I don’t have access to my library.

Happily I remember exactly where the quote came from. It was from someone who taught me a great deal - the late Paul Brunton. I think that Paul probably did more to introduce Ramana Maharshi to the West than anyone else, and he was also a close friend of Aurobindo. He once commented that it was rather convenient that two of the greatest sages of the 20th century only lived 65 miles apart!

He also mentions Ramana’s comment in Chapter 9, paragraph 23 of Volume 16 of The Notebooks of Paul Brunton.

Here’s the exact quote:
"That these differences of view exist even among illumined mystics is a striking but rarely studied fact. Why did Ramana Maharshi poke gentle fun at Aurobindo’s doctrine of spiritual planes?"

I do not know off hand whether there are any websites that specifically discuss their - respectful - differences of opinion.

If that does not give you what you need, please do let me know: I shall be home in a couple of days and I’d be happy to do a bit more digging in my library: I have over 12,000 volumes, and there are quite a lot of lesser known titles in there. Since I raised it, I shall also have a look online when I get home.”

The reason for re-printing this correspondence is this. Regular readers will know that my blog entries are festooned with links, citations and references. That is very deliberate. This blog is a bit different from most of the other medical ones out there in that I try to ensure that you can check everything that I say.

The other day I had the privilege of speaking to the Rotary Club of New York and mentioned that I had written something about five strategies that can dramatically reduce your risk of developing Alzheimer’s disease as well as discussing some of the evidence concerning nutrition and neurogenesis: the production of new neurons. I was asked what they were, and I recommended that people asking the question should check out the article. The reason was simply this: I wanted them to see the evidence for themselves.

I think that we have all had enough of people simply expressing opinions.

Now is the time for people who are writing on line – or anywhere else for that matter – to provide data to support what they are saying.

If you need further reading material on any of the topics that I write about, just let me know: I have access to a great many sources that are not always easy to get at.

I just had a very nice question from someone who had seen my article in which I commented on the way in which I had seen qigong masters treat patients without touching them.

Dear Dr. Petty,
That’s really interesting, and if it’s true, it would be very important for the future of therapy. Is that actually any scientific evidence to support what you said?

Good question, and yes, there is. But not very much of it.

A recent study from South Korea examined the effects of Qi therapy, also known as external qigong. During the study they looked at the effects – if any – of touching the patient. The researchers examined the impact of treatment on anxiety, mood, several hormones and cellular immune function. Whether or not they were touched, the patients showed improvements in anxiety, alertness, depression, fatigue, tension and cortisol levels. Treatment at a distance was just as good as hands-on treatment with one interesting exception: treatment at a distance caused the white blood count to rise slightly, while the effect wasn’t seen in people who were touched.

There is also another type of research in which qigong practitioners have tried to influence either animals or cells in culture. In one recent study practitioners directed their intention toward cultured brain cells for 20 minutes from a minimum distance of 10 centimeters. The first study seemed to show an effect on the proliferation of the cultured cells, but the second did not, showing the difficulty of doing experiments like these.

More experiments like these are underway in centers throughout the world, and I shall continue to report on both the positive and negative studies.