It turns out many ordinary medications don’t just affect our bodies – they affect our brains. Why? [Why? Seriously?!]

…One reason medications can have such psychological clout is that the body isn’t just a bag of separate organs, awash with chemicals with well-defined roles – instead, it’s a network, in which many different processes are linked.

…The world is in the midst of a crisis of over-medication, with the US alone buying up 49,000 [tons] of [acetaminophen] every year – equivalent to about 298 [acetaminophen] tablets per person – and the average American consuming $1,200 worth of prescription medications over the same period.

…There was shockingly more evidence than I had imagined,” she says. For one thing, she uncovered findings that if you put primates on a low-cholesterol diet, they become more aggressive.

…There was even a potential mechanism: lowering the animals’ cholesterol seemed to affect their levels of serotonin, an important brain chemical thought to be involved in regulating mood and social [behavior] in animals. Even fruit flies start fighting if you mess up their serotonin levels, but it also has some unpleasant effects in people – studies have linked it to violence, impulsivity, suicide and murder.

If statins were affecting people’s brains, this was likely to be a direct consequence of their ability to lower cholesterol.  

…There’s much more of an emphasis on things that doctors can easily measure,” she says, explaining that, for a long time, research into the side-effects of statins was all focused on the muscles and liver, because any problems in these organs can be detected using standard blood tests.

…“There is a remarkable gap in the research actually, when it comes to the effects of medication on personality and behaviour,” he says. “We know a lot about the physiological effects of these drugs – whether they have physical side effects or not, you know. But we don’t understand how they influence human behaviour.”

Mischkowski’s own research has uncovered a sinister side-effect of [acetaminophen.] For a long time, scientists have known that the drug blunts physical pain by reducing activity in certain brain areas, such as the insular cortex, which plays an important role in our emotions. These areas are involved in our experience of social pain, too – and intriguingly, paracetamol can make us feel better after a rejection.

…Recent research has revealed that this patch of cerebral real-estate is more crowded than anyone previously thought, because it turns out the brain’s pain centres also share their home with empathy.

For example, fMRI (functional magnetic resonance imaging) scans have shown that the same areas of our brain become active when we’re experiencing “positive empathy” –pleasure on other people’s behalf – as when we’re experiencing pain.

…The results revealed that [acetaminophen] significantly reduces our ability to feel positive empathy – a result with implications for how the drug is shaping the social relationships of millions of people every day. Though the experiment didn’t look at negative empathy – where we experience and relate to other people’s pain – Mischkowski suspects that this would also be more difficult to summon after taking the drug.

…Empathy doesn’t just determine if you’re a “nice” person, or if you cry while you’re watching sad movies. The emotion comes with many practical benefits, including more stable romantic relationships, better-adjusted children, and more successful careers.

…Scientists have known for a while that the medications used to treat asthma are sometimes associated with [behavioral] changes, such as an increase in hyperactivity and the development of ADHD symptoms.

…Back in 2009, a team of psychologists from Northwestern University, Illinois, decided to check if antidepressants might be affecting our personalities. [Isn’t that how they work?] In particular, the team were interested in neuroticism. This “Big Five” personality trait is [epitomized] by anxious feelings, such as fear, jealousy, envy and guilt.

…“We found that massive changes in neuroticism were brought about by the medicine and not very much at all by the placebo [or the therapy],” says Robert DeRubeis, who was involved in the study. “It was quite striking.”

The big surprise was that, though the antidepressants did make the participants feel less depressed, the reduction in neuroticism was much more powerful – and their influence on neuroticism was independent of their impact on depression. The patients on antidepressants also started to score more highly for extroversion.

…There’s solid evidence that the drug L-dopa, which is used to treat Parkinson’s disease, increases the risk of Impulse Control Disorders (ICDs) – a group of problems that make it more difficult to resist temptations and urges.

Consequently, the drug can have life-ruining consequences, as some patients suddenly start taking more risks, becoming pathological gamblers, excessive shoppers, and sex pests. 

…The association with impulsive behaviours makes sense, because L-dopa is essentially providing the brain with a dose of extra dopamine – in Parkinson’s disease the part of the brain that produces it is progressively destroyed – and the hormone is involved in providing us with feelings of pleasure and reward.

Experts agree that L-dopa is the most effective treatment for many of the symptoms of Parkinson’s disease, and it’s prescribed to thousands of people in the US every year. This is despite a long list of possible side effects that accompanies the medication, which explicitly mentions the risk of unusually strong urges, such as for gambling or sex.

The medications that change who we are – BBC Future

hmmm