For some time, it has been widespread medical practice to treat a range of psychological conditions, including depression and anxiety, with what might be called mind-altering drugs, namely selective serotonin reuptake inhibitors (SSRIs), which, as the name suggests, affect levels of serotonin in the brain. But there’s one mental category that isn’t considered appropriate for any kind of biomedical intervention. It’s arguably the most talked about of all human states, the cause of much of our finest art, literature and music, and it is celebrated or, depending on your view, commercially exploited once again on Friday: love.

It may be a many splendoured thing, but love is a condition for which there is famously no cure. All you need is love, as the song said, but money can’t buy you it. It’s viewed as an emotional ideal and yet the source of untold pain and suffering. Ask any 10 people what love is and you’re sure to get 10 different answers. Unsurprisingly, given that it is the stuff of romance, we tend to romanticise it. Millions of words have been spilled in trying to describe the feeling, but not many have been devoted to the biochemical processes that lie behind it.

In their new book, Love Is the Drug, Oxford ethicists Brian Earp and Julian Savulescu point out that this neglected aspect of love is just as important as its social or psychological structures. Intuitively, perhaps, we’ve always known this. After all, how do we explain the lack of interest felt on a new date? “There was no chemistry.”

We just need to identify those cases where intervening with drugs or psychology will improve authenticity Brian Earp, ethicist

Yet while we have largely come to accept that drugs that affect the brain have a part to play in treating psychological illnesses, the idea that the same approach could apply to love goes against the grain. We think of love as natural and healthy and therefore not something that is in need of what Earp and Savulescu delicately call “biomedical enhancement”.

The authors, however, argue that it’s time to change our attitudes and explore the possibilities offered by breakthroughs in biomedicine and neuroscience. “If it becomes possible to safely target the underlying neurochemistry that supports romantic attachment, using drugs or other brain-level technologies,” they write, “then there is reason to think this could help some people who really need it.”

They go further and suggest that such drugs have already been partially tested, have been used by huge numbers of people around the world, and should urgently become the subject of controlled research. The problem is the drugs they’re talking about are illegal psychoactive substances such as psilocybin and, in particular, methylenedioxymethamphetamine (MDMA), the active ingredient in the rave drug ecstasy.

They cite studies that show positive results for the use of MDMA in counselling those suffering from post-traumatic stress disorder (PTSD) and speculate that similar outcomes might be expected for couples whose relationships have hit the rocks.

But isn’t that a bit of an inductive stretch? What does the effect of, say, fighting in Iraq have to do with failing romances? Earp points out that there is already a small study showing how couples in which one partner has PTSD have benefited from the regulated use of MDMA. The way the drug is thought to work on PTSD sufferers, he says, is by breaking down the defence mechanisms that prevent their being able to open up.

“Our point is that trauma falls on a spectrum and relationships themselves can be traumatic,” he explains. “What causes a lot of relationships to break down over time is traumatic or semi-traumatic events that take place either inside or outside the relationship. People start to close down and stop sharing with their partners. Insofar as love requires a certain kind of intimacy, the defence mechanism and the kneejerk fear responses that we build up around talking about certain issues with our partners are the very things that this drug directly enables us to overcome.”

As may be gathered from that response, Earp is not interested in bringing biomedical enhancement to first dates, for reasons of what he terms “authenticity”. He wants to focus on those who have already passed that initial chemistry test and whose love has subsequently become worn and torn by the everyday rigours of life.

“If you take a drug that all of a sudden makes you feel much closer to someone than you did five minutes ago, there’s a risk that it’s the drug doing the work rather than some sort of established compatibility between you and the other person,” he says. “I think it was Timothy Leary who coined the term ‘instant marriage syndrome’, where people would meet someone at a dance and think, ‘Ooh, I’ve met my soulmate’ and they’d go and get married and as the drug wore off, and they got to know each other better, they found they didn’t actually have good compatibility.”

Of course MDMA is best known in this country for its starring role in the so-called second summer of love in 1988, when a generation of rave-goers discovered ecstasy, got “loved up” and shared the mass euphoria of dancing all night in an urban warehouse or field. The social idealism glimpsed at the beginning of that social movement soon spiralled into hedonistic excess, and it wasn’t long before stories of teenage deaths related to taking the drug ruined the utopian dream.

Though largely unheard of in the UK before that summer, MDMA was already technically illegal for more than 10 years under umbrella legislation concerning phenethylamines. In the US, it was not made illegal until 1985. Earp and Savulescu are not now calling for its wholesale legalisation. They acknowledge its potential dangers, particularly if taken in the wrong situation with inadequate support, and argue that it should only be available in a therapeutic setting, under the guidance of a professional.

Facebook Twitter Pinterest Kristin Kreuk and Adam Sinclair in Ecstasy, an adaptation of Irvine Welsh’s 1996 story The Undefeatured, set amid ecstasy users in the rave scene. Photograph: Intandem Films/Allstar

Until 1985, as Love Is the Drug reminds us, MDMA had been used by many relationship counsellors in the US. In 1998, psychiatrists George Greer and Requa Tolbert wrote in the Journal of Psychoactive Drugs, of their experience of conducting MDMA-enhanced therapeutic sessions with about 80 clients in the first half of the 1980s.

These clients had to give their informed consent and were selected after a pre-screening process. Then Greer and Tolbert would meet the clients in their homes, where they would administer a pure dose of between 77mg and 150mg of MDMA, with a 50mg booster if requested later on (the street drug in the UK is said to contain upwards of 150mg, and occasionally as much as 300mg). According to Greer and Tolbert, 90% of their clients benefited from MDMA-assisted psychotherapy, with “some”, as Earp and Savulescu write, “reporting that they felt more love toward their partners and were better able to move beyond past pains and pointless grudges”.

A cynic might say, what’s left of love after that? But a more serious point is how to distinguish the relationships that are worth saving or enhancing from those that are fundamentally dysfunctional, when there might be a danger that the temporary high could help disguise the dysfunction.

Earp and Savulescu are careful not to be too prescriptive in their definitions of love, allowing that it’s pretty much whatever those who declare possession of it say it is. Equally, Earp is on guard for external paternalistic judgments of other people’s relationships. His belief is that there is a monogamy/promiscuity spectrum along which we all fall and that no position on it is more “natural” than any other. So one-size-fits-all classifications are destined to miss the mark.

“I think it would be a mistake to say everyone should be lifelong monogamists, no matter what, and we’re going to enforce that through the criminal code,” he says. “But it would also be a mistake to say that we’re all just bonobos and monogamy is a thing of the past and we should have as many sexual partners as we can find. In the world of meaning, subjective experience and how we relate to each other, there’s a lot of room for diverse interpretations of what’s valuable.”

History has a bad track record of deciding what the “right” relationship is, says Earp, noting that it was only very recently that homosexual love was brought within the fold of acceptability. But there is one objective criterion to which the pair do hold firm. “When it comes to violent abuse, we’ve drawn a pretty strong line in the sand collectively as a society,” he says. “That is a very strong signal that it’s objectively a bad relationship.”

The book makes several bold claims that seem the product of marketing needs rather than hardcore scientific fact. For example, it states that the “biological underpinnings of romantic love are being revealed” and that the prospect of real love drugs is upon us. But there remains a great deal of debate, not to say confusion, about the workings of even such fundamental biological constituents as the hormone testosterone regarding its role in the libido. And as you might expect from professional ethicists, the book is at its most impressive when considering the moral, social and pragmatic issues concerned with scientific development, rather than the details of the development itself.

If and when the aforementioned biological underpinnings are revealed, and we are able to regulate emotions and behaviour through biomedical supplements, does that suggest we will become somehow less autonomous and, consequently, more like a programmable machine?

“There are lots of ways we take steps to try to shape ourselves and our self-narratives,” says Earp. “There are ones that we’re comfortable with because they don’t seem to involve the brain and we’re a little bit scared of interacting with the brain directly.”

But the fact is, he says, even words can affect our brains. He cites the example of the Oedipus myth. One moment he’s happily having sex with Jocasta, feeling love towards her, the next he discovers that she’s his mother. “He hasn’t taken any drugs but you can bet that all of a sudden his testosterone levels will plummet and his libido will drop.”

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Our neurochemistry is changing all the time, says Earp, and one way that can happen is by the direct administration of drugs, which have their own benefits and risks.

“We just need to identify those cases where intervening with drugs or psychology or changing our social circumstance will be likely to improve authenticity or autonomy rather than detract from it.”

He speaks with such reasoned composure on the subject that it comes as a surprise to learn that he has never taken MDMA himself.

“I’ve been interested in that experience but I haven’t had the opportunity to go forward with that because it remains unjustly and inappropriately prohibited,” he says.

The solution, he insists, is open research. In the meantime, we’ll just have to continue fumbling away in the dark, breaking up and making up, trying to understand not just ourselves but the other person – at least until the love drug arrives.

Microdosing: the perfect prescription?

In praise of ecstasy

Small studies have found that doses of MDMA can have beneficial effects for ex-military and first-responder PTSD sufferers; however, treatment takes place in controlled environments assisted by psychotherapy. There is no good evidence that recreational microdosing is effective or advisable.

Pot potential

Quality research on the effects of microdosing cannabinoids – THC and CBD – is nascent. A 2017 study found that very low doses of THC reduce stress, yet higher doses increase anxiety. In other studies, CBD has shown potential in the treatment of insomnia and a range of anxiety disorders.

Spore lore

In a recent episode of Netflix’s The Goop Lab, employees of Gwyneth Paltrow’s “wellness” company decamped to Jamaica to microdose with magic mushrooms in order to solve various emotional or trauma issues. Although many Silicon Valley types are advocates, there is little high-quality evidence that this is effective.

Love is the Drug by Brian Earp and Julian Savulescu is published by Manchester University Press (£20). To order a copy go to guardianbookshop.com. Free UK P&P on all online orders over £15