So many people love eating chocolate, and believe it is a mood-influencing food giving pleasure plus a lift in mood – a happyfood!
Now research suggests that many depressed people really do eat more chocolate. These findings came from both men and women who scored high on a psychometric depression scale but who were not receiving medication. There were no reported increases in other antioxident-rich foods, or other sources of caffeine, fat or sugar, between these depressed adults and non-depressed adults, just the increased chocolate consumption. What is not known is why the chocolate intake increased.
The evolutionary hypothesis explains our liking of chocolate as a combination of pleasures – the sweetness, the creamy texture in the mouth perhaps in some way reminiscent of breast milk – with the high energy-denseness of this food. But there is a complete lack of evidence that breast milk, even in mothers who do eat a lot of chocolate, has any chocolate flavour! So this does not explain why consumption of chocolate rather than any other sweet and creamy food increased in depressed people. Is it the pleasure which is the key factor? Or is it the cultural perception of chocolate as a reward food? Or is there another reason?
Whilst it’s been known for years that lithium drugs help many bipolar patients to manage their disorder, it hasn’t been known how lithium acts. But now there is a clue! Laboratory studies show a link between lithium and an enzyme known as PO*. This enzyme controls a group of genes which affect brain cells’ sensitivity to lithium. And one of those genes, ImpA2, is also associated with bipolar disorder in some sufferers. So possibly there is a functional connection between ImpA2 and bipolar disorder, which can be mediated by lithium. Understanding this link could lead the way to better treatments for bipolar depression.
We’ve known for ages that far more females than males suffer from depression and anxiety disorders, but it is frequently hypothesised that this is not the true state of things. This is because, in Western industrialised cultures, it is more acceptable to admit vulnerability especially psychological vulnerability if one is female, not male. The macho nature of these cultures is, if you like, a confounding variable. However, there could be more to this than social and cultural relativism.
A recent interesting finding in rats shows that females are definitely more sensitive to stress. Their brain cells respond far more strongly to the precursor to corticosteroid stress hormones, a neurochemical called corticotropin-releasing factor, CRF. Female rat neurons are activated by CRF, male rat neurons adapt to it and less stress hormones are produced.
But does this rat behaviour also happen in humans? Well, we don’t know; but we do know that CRF regulation gets disrupted in human stress-related psychological disorders, so there could be a similarity, although one needs always to be very careful in generalising between species.
Three recent small studies (see here or here) looked at the effects of various 12-16 week exercise programmes on sufferers from schizophrenia. The types of exercise varied from more physically strenuous ones, such as strength training and jogging, to less energetic yoga.
There were small improvements in physical health but greater improvements were found in mental states. Improvements in anxiety and depression from exercise were greater than similar improvements in standard care without an exercise component.
These studies support the findings of two earlier studies, which suggests the importance of further research into the effects of exercise programmes in the treatment of schizophrenia plus initiatives looking into how to implement such programmes and engage sufferers in taking part.
Some sleep disorders are well known – sleep-walking for example. But in very unusual cases people who sleepwalk behave in a highly unusual way, this is a very rare form of the disorder somnambulism when they commite violent acts.
In 2008 in the UK a middle aged man with a long history of sleep disorders actually killed his wife whilst they were both asleep. This tragedy happened when they were on holiday and the man in question had decided not to take his medication. He had a nighmare, thought he was struggling with assailants, but when he woke he found his wife dead. There is no reason to suspect that the couple were not happy together, and sleep disorder experts and the police accept that this unhappy case is one of temporary “insane automatism”.
Long-time depression researcher Eva Redei recently reported some of her latest findings. She has spent decades breeding rats who are severely depressed (mating depressed rats with depressed rats so you get ‘who are believed to be the most depressed rats in the world’ (!!)). This meant she could identify genes linked to depression. Next she exposed a different group of rats to stressful situations for two weeks which enabled her to identify the genes that consistently were associated with a poor response to stress.
The big news is that there was no overlap between the depression genes and the stress genes. This suggests that the idea that stress causes depression may be wrong. And, furthermore, she claims the reason antidepressants are often ineffective is because they treat stress and not depression and she has now shown that the two are not linked, though they may co-occur. So that’s one reason why antidepressants only work for some people (those suffering from stress and depression). Before you say ‘ah well, this is just an effect in rats’, Redei claims that rat brains are very similar to human brains, so it is reasonably to draw analogies. It also may explain why we like cheese. (No, that last bit was a joke).
“Some products that have been on the market for decades, like Prozac, are faltering in more recent follow-up tests. In many cases, these are the compounds that, in the late 90s, made Big Pharma more profitable than Big Oil. But if these same drugs were vetted now, regulators might not approve some of them. Two comprehensive analyses of antidepressant trials have uncovered a dramatic increase in placebo response since the 80s. One estimated that the so-called effect size (a measure of statistical significance) in placebo groups had nearly doubled over that time. It’s not that the old meds are getting weaker, drug developers say. It’s as if the placebo effect is somehow getting stronger.”
Many of you will be familiar with the excellent BBC radio series called Mind Changers which has included programmes on Milgram, Piaget, Ainsworth, Bartlett, Kohlberg, Zimbardo, Harlow, Asch. Some of these are currently available as podcasts here or you can go to PsychBLOG where Jamie has downloaded some and there are also some available on Spokenword (free subscription for teachers).
