Some time ago – for reasons that will become apparent I am not allowed to say when, exactly – the American writer Ayelet Waldman scored some LSD. She did this, not on a street corner or via the dark web, but middle-class style, through an acquaintance of an acquaintance, for which reason the drug arrived at her home in Berkeley, California, in a stamp-encrusted brown paper package whose sender (an elderly professor, she believed) identified himself only as Lewis Carroll, a “fellow resident” of her town. Mr Carroll had, however, troubled to write her a brief note. “Our lives may be no more than dewdrops on a summer morning,” it said. “But surely, it is better that we sparkle while we are here.” The bottle he enclosed contained 50 drops of “vintage quality” LSD, of which he advised her to take two at a time. Waldman was delighted. Not to put too fine a point on it, she believed this drug might save her life.

‘I was in a dangerous place, doing everything to ruin my own life’

For as long as she can remember, Waldman has been held hostage by her moods. When she is up, she is up; when she is down, she is down. These highs and lows she has managed over the years with the help of therapy and a number of drugs, with which she has had varying degrees of success. At the time of the parcel’s arrival, though, she had entered a new and much more scary phase.

“I was so profoundly depressed,” she says. “It wasn’t the kind of depression where you fall into bed. I’ve been through that before, and while it’s grim, it’s manageable. This was more of a mixed state, a kind of activated depression, and that’s a dangerous place to be. I was doing everything I could to ruin my own life. I was afraid that if I stayed on that track, I would force my husband to leave me, and that I would probably attempt suicide – and being a very capable person, I don’t think a failed attempt was on the cards.”

It was while she was in this state of mind that she stumbled on The Psychedelic Explorer’s Guide, by the psychologist and writer James Fadiman, who since 2010 has been collecting reports from individuals who have experimented with regular microdosing of LSD and psilocybin, a naturally occurring chemical found in a variety of mushrooms. Fadiman’s book is certainly not the result of a scientific research project; there has never been an officially sanctioned study of microdosing.

Here comes happiness: Ayelet Waldman at home. Photograph: Barry J Holmes/The Observer

But the people whose accounts it gathered together spoke repeatedly of experiencing, thanks to LSD, increased focus and better mood. They reported rarely losing their tempers, and becoming more fun to be with. None, moreover, had suffered any side effects. To put it simply, they went to bed feeling they had enjoyed that most elusive of things: a really good day. As Waldman read on, she grew envious. How she needed to have one of those! Was this her glimmer of hope? She thought it might be.

‘Within a couple of doses the computer of my brain restarted’

Waldman contacted Fadiman, and received a memo entitled “To a Potential Self-Study Psychedelic Researcher”. The protocol was simple. In order to participate in his international self-study group on the effects of sub-perceptual doses of LSD, she should take a microdose of the drug every third day. The suggested dose was a minuscule 10 micrograms, one 10th or less of what a person would have to take in order to experience an altered state of consciousness (ie to trip).

Meanwhile, she should lead life as normal, pausing only to record her moods, productivity and physical symptoms. Did this sound – to be blunt – preposterous? It did. Waldman is a middle-aged mother of four who, in addition to writing novels, lectures on the criminal justice system (she is a Harvard-educated former lawyer). As someone who is law-abiding and swotty, nothing in the world irritates her more than hippies, slackers, free spirits. Even people who won’t stay on the right hand side of escalators drive her nuts. Ken Kesey she is not. But she was suffering. She had nothing to lose. Why shouldn’t she try it, just for a month?

Having found a supplier, then, she did indeed begin taking the drug, an experience she has now recorded in her own book A Really Good Day: How Microdosing Made a Mega Difference in My Mood, My Marriage, and My Life. Its publication is certain to cause controversy. In fact, the madness has already begun. When we speak via Skype, a month or so before it arrives in bookshops, she tells me that only a few days earlier an excitable reporter got in touch to inform her that his editor had given him permission to “drop acid with Ayelet Waldman”. (Her response to his question about when they might schedule this journalistic endeavour was: “Like, never.”)

Loved up: Waldman and husband Michael Chabon. Photograph: Albert L Ortega/WireImage

Attitudes to drugs in America are – irrespective of those states that have legalised cannabis – far from liberal. “Trump has appointed to the Department of Justice a war-on-drugs advocate [the Alabama senator, Jeff Sessions] who is so retrograde in his thinking, he believes the US suffers from an under-incarceration problem,” she says. It’s for this reason that she won’t reveal when her experiment ended: there is a three-year statute of limitations on drugs charges. “Do I think a white, middle-class lady will be high on his list of targets? No. But in this crazy new world we live in, you can’t be too careful.”

Its reception will also doubtless be muddied by the fact that she is its author. In America, Waldman is well known as an acclaimed writer in her own right and as the wife of the Pulitzer Prize-winning novelist Michael Chabon, to whom she has been married since 1993. When she writes about herself, moreover – and this is something she does a great deal in A Really Good Day – people have a tendency to respond with unnerving fury.

'My husband encouraged me to embark on LSD experiment because he was desperate, too'

Most famously, this was the case in 2005, when the New York Times published her essay Motherlove, in which she declared that she loved her husband more than her children (“If a good mother is one who loves her child more than anyone else in the world, I am not a good mother. I am in fact a bad mother.”) In the days that followed, ABC’s daytime show The View hosted an unaccountably vitriolic debate about Waldman, her neighbours could be heard tearing her to shreds in Starbucks, and her inbox filled with emails from strangers threatening to report her to social services, the better that her children might be taken away.

Waldman is clever and funny and open-hearted. But as she readily admits, even her more sympathetic readers may sometimes have cause to wonder, in the case of A Really Good Day, which aspects of her behaviour – her compulsion to tell the world things that others might prefer to keep private among them – are simply the result of her personality, and which can be attributed to her illness. “It is hard to distinguish between them,” she says, almost wonderingly.

Still, she is probably better placed, now, to cope with any onslaught. Waldman is no longer using LSD – her experiment really did last for only a month – but its effects have, in some ways, been lasting. “I miss its anti-depressant quality, and I miss the way it made me focus. It was like Ritalin [a drug commonly prescribed in the US to children with ADHD] without the side effects, which is frankly incredible. But that month got me out of a dark place. Within the first couple of doses, it was like the computer of my brain had been restarted. I was still moody. I had some really good days, but there were also crappy days, and days when it was just the normal shit. Somehow, though, the bad days were not hellish days, and so I had the capacity to work on issues I just couldn’t before. Sure, I was hoping for joy. What I got instead was enough distance from the pain I was in to work on the things that were causing it.”

Expand your mind: 1960s LSD advocate Dr Timothy Leary, who advised us to ‘turn on, tune in, drop out’. Photograph: AP

That work continues. “I’m still not on an even keel. I’m still struggling with my moods. But I’m committed to that. I’m doing a new kind of therapy that is working quite well, even if not quite so well as it might be if I was still microdosing.” If someone sends her a mean tweet in the coming weeks, she is unlikely to respond as venomously as she might once have done, or even at all.

Given its benign effect on her, why didn’t she just find herself a new supplier, and continue taking it? There were, she says, two reasons. The first was her complete inability to purchase illegal drugs: towards the end of her book, she describes how, having made contact by text with a dealer, she panics, having convinced herself that “Lucy” is a police informant. The second was her determination to write a book about her experience: for that to be safe, she had to no longer be using.

“If I could have overcome those things, there is no doubt in my mind that I would have carried on. Of course, it might not have kept working; I’ve been on medication before that seemed to be working, and then wasn’t. But if it was to be made legal, I’d be the first in the queue, and I periodically remind myself that, if I get desperate again, I do have the option.”

Her book is well-researched and, in the matter of LSD itself, careful and no-nonsense. The drug, a variation on the ergotamine molecule (ergot is the fungus responsible for the disease known in the Middle Ages as St Anthony’s Fire) which was first synthesised in Basel in 1938 by Dr Albert Hofmann, has, she argues, an undeservedly bad reputation. The scare stories it trails – of young men and women whose LSD hallucinations lead them to jump off high buildings – have little basis in reality. Rather, they are largely the result of conservative America’s response to the 1960s counterculture, to Timothy Leary’s suggestion that people “turn on, tune in, drop out”. Twenty million people have used it in the US, and millions more around the world, with no ill effects at all.

It’s complicated, but when it comes to the drug’s possible use in the treatment of mental illness, what you need to know is that LSD stimulates the 5-HT2A serotonin receptor, which in turn leads to the stimulation both of brain-derived neurotrophic factor (BDNF), something a pharmacologist described to her as “like Miracle-Gro for the brain… It stimulates growth, connections, and activity”, and of glutamate, the neurotransmitter most responsible for brain functions, such as cognition, learning and memory. (Hence its supposed new-found popularity in Silicon Valley, though Waldman thinks that, in reality, there are more magazine articles about tech dudes using LSD than there are, well, tech dudes using LSD: “If there were some mass secret movement, it would have been a lot easier for to get hold of my drugs.”)

She believes that during her experiment her neuroplasticity was enhanced, and that this didn’t only enable her to work for hours at a time, to achieve a real sense of “flow” at her desk, but that it also made her happier and less impulsive. What little research has been done backs her up – a study at Imperial College London showed that even a single dose of LSD “produced robust psychological effects” – though scientists still don’t fully understand the relationship between what happens in the brain, and the psyche.

Why isn’t more research carried out? The simple truth is that LSD still carries with it a lot of leftover political baggage. During the writing of her book, the few researchers sanctioned by the FDA (Food & Drug Administration) who are out there were reluctant to allow Waldman to quote them, fearing that to associate themselves with a “personal experiment” would tarnish their hard-won credibility.

So far, so good. However, when her book is on more personal territory, as it frequently is, Waldman is vastly less cautious, and for the reader – especially, perhaps, the British reader – this can be, well, excruciating. “I know!” she says, when I tell her this. “Can you imagine what it would be like for me if I lived in London?” Chabon, a feminist with whom she shares the childcare, has the power of veto over everything she writes. But because he’s a writer, too, this seems not to be something he often invokes. In A Really Good Day, nothing is out of bounds, from their agonising couples therapy (“My husband’s eyes filled… I collapsed in his arms, crying so hard I soaked his shirt”), to their sex life (“‘I know you love me,’ I said, as we made love”), to their periodic use of MDMA, aka ecstasy, as a way of “opening up” their lines of connection. “What we did was talk,” she writes, of the first time they tried it, in a hotel room they’d booked specifically for the purpose. “For six hours, we talked about our feelings for each other, why we love each other, how we loved each other.”

Waldman reveals that her moods can be “triggered” by everything from her writerly insecurities, to the dog, to the sound of her husband eating nuts (she suffers from misophonia, or selective sound sensitivity syndrome): “I handed him a handful of almonds, and walked out of the kitchen… I heard a crunch, the smack of lips; I felt a wave of anger.” She is also fed up that her husband earns more than her, and that she has to share his writing studio, which has an uncomfortable couch: “Though he’s welcomed me in, I feel like a girlfriend who’s been given a drawer in the bachelor pad bathroom.” Poor Michael Chabon. The reader begins to feel he is some kind of saint.

“Well, he is somewhat saintly,” Waldman says. “He makes my friends crazy. He gives great gifts. He has impeccable taste in clothes and jewellery. He is a know-it-all, but then, he does sort of know everything. He’s misanthropic, in that we [the family] are all he has space for; he doesn’t have any close friends, which I think he would benefit from. I was about to say that he’s far better than I deserve, but that’s the pathology speaking, because I am a very good wife for him.”

Isn’t he ever mean to her? “Yeah, sure he is.” He encouraged her to embark on LSD experiment because he was desperate, too.

Before we hang up, I have to ask: does she ever worry her extraordinarily intense relationship with Chabon – on Twitter she has been known to post pictures of her husband, along with a line informing her 15,800 followers just how much she loves him – might be another symptom of her illness? For the first time in our conversation, she is hesitant. The gale of her voice drops to a light breeze.

“Yeah, I have thought about this. I have said to him: ‘If I were to get healthy, would I still love you, and would you still love me?’ There is a way that I’ve confused needing with loving. I don’t want to sound like a Hallmark card, but love is [supposed to be] unselfish, and in my most internal, whirling dark places, I think I need him so badly because he takes care of me, protects me, makes me feel safe. One of the things that saved our marriage in that [dark] period was when I brutally tried to disentangle those things.”

The upshot is that she thinks, now, perhaps it’s OK to need him. “After the LSD, when I was having this intense new therapy, I took a drive one night in northern California, where the countryside is very beautiful. I had this thought: maybe I don’t love him after all. It was terrifying, and I was crying. But then the phone rang, and it was him.” How did she feel then? “His voice filled me like a glass of water.”

‘People have been curious, even excited’: an extract from ‘A Really Good Day’

A few days ago, I began tentatively to tell people about this experiment. To my surprise, I encountered few negative reactions. Every once in a while a listener might arch an eyebrow or smile uncomfortably, as if trying to figure out whether her discomfort meant that she wasn’t hip enough, or whether I really was nuts. But those have been in the decided minority. Most people have been curious, even excited.

Those with histories of mood disorders were intrigued to hear that my spirits have lifted, that though I sometimes feel the familiar clutch of anxiety in my chest, I am generally able to use mindfulness techniques to make it dissolve. When I told them that I have not gained weight and that my libido has not withered away, they got really excited. The side effects of SSRIs are so ubiquitous and unpleasant that the idea of a medication protocol with fewer of them is thrilling.

Friends who incline to the spiritual were disappointed when they heard that I’ve experienced no connection to the divine, but reassured when I mention the pleasure I’ve taken in the natural world, the tree outside my window, the smell of the jasmine beside the city sidewalks. Risk takers and hedonists were disappointed that I was unable to provide details of hallucinations. No kaleidoscopic colours, they asked wistfully, no feeling that the floor was shifting beneath your feet? I live in California. The last thing I want to feel is the floor shifting beneath my feet. They urged me to try a ‘real’ dose. It would change my life, they said, as though my problem is that my life has been too devoid of weirdness. Besides, my life is changing.

Tonight, however, was a different story. These two writer friends are about 20 years older than my husband and me, which puts them firmly in the boomer generation. They were in their 20s in the 1960s. They’ve travelled the world, rejected a life of secure conformity in favour of the risks and rewards of art. What better people to confide in? I thought.

‘Well,’ I said, ‘I’ve been writing, but not working on a novel. I’ve been writing about microdosing with LSD.’

What does that mean, the woman of the pair asked? Are you writing some kind of nonfiction article on people who use LSD?

I took a breath and then explained.

Her face froze. If she had been wearing pearls, she would have clutched them. She looked horrified, even disgusted, as if I’d told her that I’d taken up murdering baby seals. Her husband’s reaction was only slightly less disturbing. He smiled uncomfortably and changed the subject. I immediately agreed, yes, the antipasto was delicious, and, no, I didn’t want any more.

Their reaction launched a series of cascading anxieties. Will I be condemned for doing this? Will people reject me as a nutcase, a crank, a deluded acid freak? Will I lose whatever credibility I have in the world? Will parents not let their children come over to our house any more, under the misapprehension that I keep drugs in my home?

As soon as dinner was over, I tried the technique for dissipating anxiety that my cognitive behavioural therapist recommends. I took a few deep breaths, exhaling for half again as long as I inhaled. My chest and throat unclenched. The anxiety ebbed. I was calm again. I was OK.

Also, I had some perspective. This couple were young in the 1960s, when Timothy Leary was spreading the gospel of psychedelic recklessness. For all I know, they had complicated histories with the drug that influenced how they responded to me. In all likelihood, their discomfort had far more to do with them than with me.

A Really Good Day: How Microdosing Made a Mega Difference in My Mood, My Marriage, and My Life by Ayelet Waldman is published by Corsair at £13.99. To order a copy, go to bookshop.theguardian.com