"If I’d done this interview two years ago,” I tell Dr Hugh Selsick when we meet, “I’d have spent most of it crying.” Not because jovial Dr Selsick has that effect, but because he’s an insomnia specialist, and it’s so rare to see a doctor who truly understands.

I’ve had sleep problems for 16 years, experiencing periods of barely sleeping, nightly panic attacks and mind-numbing wakefulness, crashing out in meetings and sobbing at 3am from sheer frustration.

I’ve seen all manner of sleep therapists. What I haven’t had is a doctor who can speak from firsthand experience, as Dr Selsick can.

Before university he spent a year in Israel on the Machon programme. Living on kibbutz, he struggled with sleeplessness, exhausted from the early starts but unable to nap in the afternoon. Returning home to South Africa he developed really bad insomnia for several months. “It just resolved one day and I don’t know why, but it was horrendous.”

He volunteeredas a subject in a sleep experiment. “While I was getting my head wired up, the professor hooked me.” Moving to London, he trained as a psychiatrist and starting to see patients at the Royal London Hospital for Integrated Medicine nine years ago.

“The thing about insomnia is it’s a completely invisible disorder. I’ve met thousands of insomniacs and I couldn’t tell you had it,” he tells me. “People feel hidden.”

Dr Selsick says people have been struggling with sleep for a long time — although shift work, noise and the 24/7 working culture may have made the problem more widespread — yet it remains poorly understood. “Most doctors don’t know how to assess it, how to treat it, or even whether it is treatable,” he says.

“It just wasn’t viewed as something that could be studied or was interesting to study.” Insomnia was often seen as a symptom of another disorder, such as depression, leading doctors to assume if they treated the latter, the former would clear up.

“Sometimes it will but often it won’t,” says Dr Selsick. “That’s a problem because insomnia is a serious disorder in its own right, and it affects quality of life.” It is a risk factor for other psychiatric disorders, “if you treat just the depression the risk of that person having another depressive episode is much higher”.

He sees up to 70 patients a week, either alone or in groups. The NHS funded clinic attracts patients from as far afield as York, Cornwall and the Channel Islands. Some, he acknowledges, sleep more than they think — people are notoriously bad at estimating their kip — but he says, “If they are feeling unwell during the day there’s a problem that needs to be treated.

“I’ve had more people crying in this clinic than in my general psychiatry clinics. Part of it is that incredible relief,” he says. “Most people have either been fobbed off by their GPs or told have a glass of warm milk before bed, or just to live with it.”

This rings true to me, having broken down in many professional’s offices. “Some of the feedback is that even if you don’t cure my insomnia the fact you realise this is a big thing in my life is enormous,” he says.

Patients are tasked with a series of actions, including making sure you get up at the same time every day however badly you’ve slept — “it’s hard but makes a significant difference” — avoiding napping, and, finally, sleep scheduling. This last solution helps around 80% of patients.

It involves restricting time in bed to match actual sleep (only spending five hours in bed if you generally only sleep for five hours) and using the bedroom only for sleep and sex, rather than spending time in it awake. After 15 minutes of attempting sleep, people are encouraged to leave the room and do something relaxing, such as listening to a podcast, until they are sleepy.

Dr Selsick sighs that the technique is badly misunderstood. “People will say I tried it for two or three nights and it was horrendous. What they don’t realise is that the point is not to make you feel sleepy on the night you do it.” Instead, it’s about destroying negative associations by conditioning a different mindset.

For good sleepers, going to bed makes them sleepy and makes them sleep — a pattern reinforced over thousands of nights. Insomniacs, however, have been to bed thousands of times, unsuccessfully. The act of doing so is associated with anxiety, frustration and —ultimately —wakefulness.

We talk about how I can be nodding off on the sofa yet wide awake moments later in bed; Dr Selsick nods: “That’s this process kicking in. The point of the technique is to break those pathways.”

With sleep scheduling, “you may spend a lot less time in bed but it’s spent asleep. Over many weeks it shifts your association of the bedroom from a place where you’re awake to a place where you’re asleep, so the act of going to bed makes you sleep.” It may take months, hewarns “but once it works, this pathway becomes so strong”.

“I ask my patients to do some really tough things so I think it does help that I can at least appreciate how much harder it is for them because they’re starting from a place of absolute exhaustion.”

If rewiring sleep patterns is the ultimate goal, in the short-term, unusually, Dr Selsick doesn’t advise against sleeping pills. With a healthy but very controlled habit, this is music to my ears. “Our philosophy s that our prime job is to get people sleeping well. Mostly that involves doing Cognitive Behaviour Therapy but sometimes that involves medication, and we would do them alongside each other.”

He compares sleeping drugs to insulin; without it a diabetic’s blood sugar will spiral “yet no one would ever say they’re addicted to the insulin”. Like insulin, pills are a treatment not a cure, and just because the condition returns when you stop the medicine doesn’t mean you’re addicted. “The vast majority who take sleeping pills do not become addicted,” he says. “There is a risk, but it’s nowhere near as common as people think.”

In response to demand, Dr Selsick is launching an online version of the treatment programme. His plan, long-term, is to focus on the most complex cases, including disorders like night terrors or sleep paralysis.

Whatever the specific complaint, it’s clear his expertise is highly sought after; even on security at Alyth Gardens synagogue, he gets asked about sleep issues. He has his share of stories, including the man who told him he drank 16 cups of coffee a day, and couldn’t understand why he wasn’t sleeping. “I said do you think that might be interfering with your sleep and he said no — after 6pm I switch to lattes.”

Passionate about Judaism and Israel, Dr Selsick looks back on his gap year as perhaps the most formative of his life “in every way”. Thirty years on, he’s emphatic that sleep is a neglected area of study.

“Most people don’t realise that help is available,” he says. “It’s a serious condition that has a huge impact on people’s lives, their jobs and the economy. ”

Whether he would have focused on sleep medicine were it not for his experience, he’s unsure. But perhaps it was pre-ordained. “It occurred to me a few years ago that maybe it was prophetic that my barmitzvah portion was Vayetzeh— Jacob’s dream,” he chuckles.

Of course, if his patients are dreaming, he must be doing something right.