December 7, 2021

I, Science

The science magazine of Imperial College

A sad soul kills you quicker than a germ. The science behind the healing power of the mind.

The mind is its own place, and in itself
Can make a heaven of Hell, a hell of Heaven.

– John Milton, Paradise Lost

Neuro-psycho-biology is the lengthy name awarded to the up and coming field of psychology-cum-genetics where researchers are taking tentative steps into understanding the healing, or not-so-healing, power of the human mind.

Patient expectations play a large part in determining the outcome of treatment; those who think mordantly experience more post surgical pain than those who don’t. Furthermore not only do optimists live longer, they experience fewer symptoms (subjectively and objectively). Short of imminently fatal events like a knife through the heart, a cheerful, relaxed attitude to health has repeatedly been shown to be beneficial. Anecdotally, this is obvious. How many of us have heard phrases similar to “she’s a fighter”? However, only recently are we starting to understand why this might be, and the implications for health.

A substantial proportion can be boiled down to the nature vs. nurture paradigm. In fact, nurture impacts nature, all through the devious fingers of epigenetics. Epigenetics describes what turns genes from a monotonous script into a living, 3D functional organism. It includes chemical changes to genes themselves, their packaging proteins and their modification machinery, that ultimately switches them on and off. Epigenetics helps to explain why identical twins are not identical and when it comes to health, it can also explain the mind’s power over the body.

Our early life has a fierce effect on future illness, namely through interaction with the stress response. McGowan et al. made headlines when they discovered that adoring rat mums increased the expression of the glucocorticosteroid receptor in their offspring’s brains (steroids are the ‘stress hormones’). Ultimately, these lucky pups were better at toning down their stress response than their peers, who received no licking, grooming and attention from their mothers. The mechanism involved an epigenetic regulatory mechanism called methylation – the addition of a methyl group to gene packaging proteins. When this process was chemically inhibited, the improved stress response vanished. Brains of suicide victims show similar methylation changes.

Stress has an important two-way interaction with the immune system. Stress hormones literally kill immune cells, and chemicals realised by the immune system affect our mood. It’s well known we’re more likely to get ill when stressed and run down, e.g. before exams or an appraisal. Strikingly, depression is associated with a 50% higher incidence of heart disease.

One study found that pleasant odours and photos evoked higher secretions of immunoglobulin in subjects, whilst yet another found happy people produced more antibodies when vaccinated for flu. An additional study showed that circulating antibodies in medical students fell just before exams.

Thus, there is a patent case for keeping calm and carrying on. In addition to suppressing the immune system, stress can induce degeneration in brain areas like the hippocampus, involved in memory and learning. Antidepressants increase levels of BDNF, a brain growth factor, in rats. In humans, anti-depressants require 4-6 weeks to become effective, an appropriate time period if gene expression is involved.

So, can we really think ourselves better? Does being happy mean we can fall back on a flourishing, bubbly pool of immune cells? Heather Whitestone, former Miss USA, deaf from 18 months, said “the most handicapped person is a negative thinker”. And sadly, no, some diseases are too far gone for anything to hold them back. Much as we’d like to, we can’t communicate with our bodies to direct immune cells to tumours or ask our hearts to build new valves.

But if we measure life in terms of quality and not quantity, which we mere mortals ought to, then ‘positivity’ reduces the impact of illness the world over. Not only can we accomplish more, but illness must confront a tougher opponent, from the immune system to the spirit. And just maybe, the result will be more time.

Cancer sufferers are sometimes known to reflect that the meaning of life experiences, which used to take months and years to understand, become almost instantaneous. Similarly, the Japanese mend broken objects with gold in their belief that damage can become beautiful.

Hence it is becoming more and more obvious that even if not precisely mind-over-matter and that optimism cannot conquer all, mental health wields an extraordinary amount of power over our physical well-being.

Moreover, if medical care continues to understand how much attitude improves health, it may reduce medication. Ideal for the patients, who experience fewer side effects. Ideal for the state, who can divert funds elsewhere.

“A sad soul can kill you quicker than a germ” said Steinbeck. With depression predicted to be the leading cause of disability by 2050, perhaps we should all be taking him seriously.

Image from