Posts Tagged ‘ Mental health ’

Vaccines and Autism – Media Report Card


Just got sent this link by the irrepressible Aimee, a “Not great” article about the Vaccines vs Autism “Debate”.

Here’s my Media Score Card for this article:

Much rubbish, a few good points. I give her a C-.

‘vaccinate at any cost’ = Strawman
Court decisions =/= Science
Incomplete knowledge = No knowledge = Fail
Anecdote =/= Good Evidence
“acceptable risk” argument simplifies risk/benefit assessment = Fail
“Teh Toxins” = Fail
Injection = Unnatural = Fail
“canaries in the coalmine” = Fail.   Can someone say “Mommy instinct”?

Respectful discussion = Win
Pro-information = Win
Complex topic = Win.

All-in-all a reasonable person sucked into the Vaccine -> Autism perspective.

Pity.

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How Narcissistic are You?


Haven’t posted anything for a while, I’m wrapped up in the warm embrace of procrastination. Thought this was interesting though and an easy post. Take the online Narcissism test.

Despite all evidence to the contrary I only scored a 4. If you score greater than 20 you probably have a mirror in your pocket right now.

Some quiz answering music for you….

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Gamblers Rewarded by Near Misses


ResearchBlogging.orgEarlier this year a study published in the Journal of Neuroscience looked at the brains of compulsive gamblers and concluded that when the the gamblers suffered “near-miss” losses their brains reacted as if they had won. Another study published slightly later in the Journal of the Experimental Analysis of Behaviour also looked at the brains of gamblers but included a control groups of non-gamblers as well. The results were interesting.

First off, what exactly is a near-miss loss? The experiments were performed with slot machine type visual stimuli so in this case lines that contained two out of three matching symbols were considered near-misses. Now from a practical stand point, as the out put is meant to be random a line like this is no closer to winning than one with three different symbols and does not predict any greater likelihood of winning in the future. Although people might realise this from an intellectual stand point it’s still hard not to think “Almost got it that time”.  Hence “near-miss”.

The second study did indeed find that gamblers reacted to the near misses more like they were wins, they also found that non-gamblers reacted to the near misses more as if they were true losses. The thing I found interesting though was that the reactions of gamblers to winning while consistent within the gambling group had nothing in common with the reaction in the non-gambling group.

A further interesting finding was that although the non-gambler group had neural responses more similar to losses when confronted with near-misses, they gave similar answers as the gamblers when asked how close they were to a win. In other words they also rated a near-miss as closer to winning than a more random looking output.

By comparing the neural activation of gamblers and non-gamblers the researchers were able to see that non-gamblers had stronger reactions to losing outcomes than did the gamblers. This makes sense in several ways, humans are generally quite loss averse. We will tend to think of a loss as more negative than a similar gain is positive ie a win of a certain amount versus a loss of the same amount do not cancel out, there is a larger negative emotional balance. In contrast, problem gamblers would be expected to view losses as less damaging over all otherwise continuing losses would result in ceasing gambling activities.

In addition the study authors linked this work with a previous study, suggesting that problem gamblers are activating regions  of their brains associated with impulsive behaviour when wins are experienced while non-gamblers activate regions associated with reflective behaviour when experiencing losses. This part of the study discussion is very interesting and worth a read in itself.

The current study is insufficient to establish the causal direction in the relationship between compulsive gambling behaviour and the network of neural activation that accompanies gambling wins. Even so it is tempting to view the brain response as predisposing a person to becoming a compulsive gambler.  If the “high” for a win is greater in certain individuals because of this difference in brain response then this might lead them to gambling abuse behaviour. I hardly think though that there will ever be wide-scale screening programmes to identify potential gamblers.

The more we learn about the functioning of the brain in these sort of situations though the better equipped we will be to effectively help those who are affected by problem gambling.

 

OpenLab2010 Submit To Open Laboratory 2010(What’s This?)


Chase, H., & Clark, L. (2010). Gambling Severity Predicts Midbrain Response to Near-Miss Outcomes Journal of Neuroscience, 30 (18), 6180-6187 DOI: 10.1523/JNEUROSCI.5758-09.2010

Habib, R. & Dixon, M.R. (2010). Neurobehavioral evidence for the “near-miss” effect in pathological gamblers JOURNAL OF THE EXPERIMENTAL ANALYSIS OF BEHAVIOR, 93 (3), 313-328 : 10.1901/jeab.2010.93-313

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Is there a Biochemical Marker for Suicide?


Suicide is a sensitive subject, by it’s very nature it seems we are obliged to treat it with kid gloves. In public it is virtually taboo to even mention suicide, in news media euphemisms are employed in order to avoid explicit use of the “S” word. Attitudes are beginning to change, with more vocal discussion about mental illness and euthanasia in both this country and abroad.

One of the key issues is whether a person is capable of deciding to end their own life or if such a decision automatically excludes them from the definition of mentally competent. I found myself pondering these things as I attempted to come up with a way to introduce the research that is ostensibly the focus of this post.

Regardless of your moral position on the subject of suicide I think we can mostly agree that identifying persons at risk of suicidal tendencies would be helpful in alleviating the pain that accompanies this choice (if indeed it can be described as such). This is where a paper published recently in PLoSONE comes in. The study authors point out in the introduction that previous work has been able to correlate increased blood brain barrier permeability with suicide in patients with prior mental disorder.

Perhaps at this point I should take a step back and provide a little more information on what we are discussing here. The blood brain barrier (BBB) is a system of control that restricts what can and cannot pass between the normal circulatory system and the cerebrospinal fluid (CSF) or the bath that your brain sits in.

In practical terms this means tight connections between the cells of your capillaries to prevent leaks and transport systems to get nutrients back and forth across the barrier. Imagine a dam made of tightly packed stones with channels for the controlled movement of water and you have the basic idea.

Anyway, if the BBB becomes more permeable then it is reasonable to suppose that proteins found in the CSF would be found in higher concentrations in the blood than would normally be expected. If the permeability of the BBB is also correlated with suicidal behaviour then the presence of these proteins become an indirect test for suicidal tendencies.

This is the hypothesis that the research then tested, ie. does the presence of proteins in the blood normally found in the CFS correlate with suicidal tendencies? This study looked specifically at a protein known as S100B, primarily associated with certain cells in the brain and spinal cord. Included in the study were 64 adolescents (average age ~14.5 yrs) diagnosed with either psychosis or mood disorders and 20 healthy control subjects.

The subjects were evaluated and their suicidality was ranked from 1-7*, Blood tests then determined the levels of S100B. The findings showed that levels of S100B significantly correlated with suicidality in the subjects. Looking at the data accompanying the study it seems there is a wide margin of uncertainty on these readings. With a relatively small number of subjects I’m not particularly surprised by this but I would be looking to see more investigation into this approach to determine it’s reliability.

Obviously this technique will not replace psychiatric evaluation, it may prove useful though in helping identify those that are most at risk of suicidal behaviour. If I may return to the broader issues I raised at the start of this post, I would also find it interesting if this test (once extensively validated) could separate those who wish to end their lives due to illness into groups consisting of those with suicidal thoughts because of mood disorders and those who are otherwise of sound mind.

Something to think about.

* 1-no suicidality is present, 2-very mild (thoughts when angry), 3-mild (occasional thoughts), 4-moderate (thoughts present in the last week), 5-moderately-severe (recurrent thoughts present almost daily), 6-severe (current suicidal plan), 7-extremely severe (patient attempted suicide within the last week)

Falcone T, Fazio V, Lee C, Simon B, Franco K, Marchi N, & Janigro D (2010). Serum S100B: a potential biomarker for suicidality in adolescents? PloS one, 5 (6) PMID: 20559426

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Is there Something Fishy about Psychosis?


ResearchBlogging.org

Psychosis is a scary word, conjuring images of people who have so lost touch with reality that they are unable to integrate with society. As with most everything else this condition exists on a continuum, mild symptoms may pose no problem for the sufferer1 nor be outwardly visible. Previous studies have seen correlations between the intake of polyunsaturated fatty acids (with the cute acronym PUFA2) and increased severity of psychotic symptoms, with this in mind a study was performed in Sweden looking at the dietary intake of fish and the incidence of psychosis symptoms in the general population.

In total 33,623 women completed the study which covered the period between 1991/92 to 2002/03 (with questionnaires at the beginning and end of this period). This group was then classified based on their answers to the questionnaires into 3 groups: Low, middle and high frequency of symptoms, where the low group included women with no symptoms. This gave a split of 18,411, 14,395 and 817 women in the groups respectively. The first question I had reading this study is how do you classify someone with psychotic symptoms? The women in the study completed two questionnaires to provide the information for this part.

The first was the Community Assessment of Psychic Experiences (CAPE, another cool acronym), this contained questions ranging from those looking at emotional states such as “Do you ever feel sad?”, to those that address personal perception like “Do you ever feel pessimistic about everything?”. Also included are the questions that we would more easily recognise as relating to psychosis such as “Do you ever feel as if a double has taken the place of a family member, friend or acquaintance?” or “Do you ever see objects, people or animals that other people cannot see?”.

There are also questions that might seem to generate positive answers from a wide range of the population that we would not consider psychotic such as “Do you ever think that people can communicate telepathically?”, a belief that if I can take what I see in the media seriously is becoming more widespread. And “Do you believe in the power of witchcraft, voodoo or the occult?” which thinking back to the furore that arose around the Harry Potter books is a view that is held by a disturbing number of people3.

Quite obviously simply answering affirmatively to these questions does not place you in the psychotic camp, it is the aggregate of these answers that matter as well as further variables that relate to these answers such as how these thoughts and experiences make you feel. The experience of seeing or hearing a loved one that has died is quite widespread but I don’t think general conclusions about the sanity of the general population can be reached using this information.

The second questionnaire was a variation on the Peters et al. Delusions Inventory (PDI, and the good acronyms come to an end). There is significant overlap between the questions asked in the PDI and the CAPE questionnaires, the main difference seems to be how each question is followed up. The CAPE approach simply asks how distressed the respondent feels if they answered affirmatively to a question (with a 4 point scale, Not distressed to Very distressed) while the PDI covers this aspect as well as asking how much the respondent thinks about it and how much they believe it is true.

Now how do the categories that I mentioned above (low, middle and high) relate to the results of the questionnaires? Rather than attempt to paraphrase the study I’ll just quote that bit:

“The “low level symptoms group” included women with no or few experiences of psychotic-like symptoms (≤3 “sometimes” and no “almost always” and “often” answers to any of the questions). The “high level symptoms group” included women with frequent experiences of psychotic-like symptoms (≥3 “almost always” or “often” answers). The “middle level symptoms group” was defined as participants not included in the low level or high level groups.”

Fairly simple, not as nuanced as I expect an in-depth psychological evaluation might be but that’s the limitation of performing a large scale study.

Finally, what were the results of the study regarding fish consumption and symptoms of psychosis? Interestingly the authors did not see a simple relationship between the two variables, there was no clear protective effect with increasing intake of fatty fish (those with high levels of PUFAs). Instead there was an optimal intake that was correlated with low (or no) symptoms, higher intake actually correlated with increased symptoms. The authors are unsure what could account for this effect stating:

“This puzzling finding may be due to unknown or known unhealthy constituents of fatty fish. For instance, environmental pollutants such as polychlorinated biphenyls (PCB) and dioxins are known to accumulate in fatty fish. Another possible explanation may be that the frequent intake of fish and PUFA may be advantageous in lower doses but disadvantageous in higher doses.”

The authors also caution that the study was not geared to determine a causal relationship between the variables merely how these were correlated4. Another interesting finding was that high levels of psychotic symptoms are also correlated with women who are both overweight and are smokers (and also for some reason migration to Sweden5).

Bottom line? Hard to say really, the results of this study are indicative but not definitive. The take home message in my book looks to be that it is a balanced diet which is most beneficial, including fish in your meals between 1 and 3 times a week or so. For those of us who aren’t keen on fish, supplements might be the answer but that’s really another question.

OpenLab2010 Submit To Open Laboratory 2010(What’s This?)

1. Indeed they may not even consider themselves to be suffering from anything untoward.

2. You might recognize Omega-3 as representative of this group.

3. For me that number is 5.

4. Remembering the adage: Correlation does not equal Causation.

5. So should the tourism board adopt the slogan “Sweden: You don’t have to be crazy to move here, but it helps”? Too insensitive?


Hedelin M, Lof M, Olsson M, Lewander T, Nilsson B, Hultman CM, & Weiderpass E (2010). Dietary intake of fish, omega-3, omega-6 polyunsaturated fatty acids and vitamin D and the prevalence of psychotic-like symptoms in a cohort of 33 000 women from the general population. BMC psychiatry, 10 (1) PMID: 20504323

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