It started to gnaw at him. There was a fear of missing out, what the Facebook generation would call FOMO, but that wasn't the worst of it. It was the fear of being unwanted.
Fear - now there's a relative concept. Vincent, playing his first test, could stand 20m away from fire-breathing fast bowler Brett Lee on the fastest pitch in the world and feel no fear, just excitement. On that day - November 30, 2001 - he announced his talent to the world with a century at Perth's WACA ground. The future looked uncommonly bright.
Yet here, he was frightened. What were his teammates doing? And why wasn't he with them? Less than two years later, Vincent's ebullience and sunny smile had disappeared. Darkness took its place.
"I just had the anxiety of feeling worthless, that I wasn't being asked out with the rest," Vincent recalled. "You're in your room, you're by yourself and nobody ever calls you to say, 'C'mon, let's go out to dinner.' You feel like an individual, not a teammate. That was my biggest issue - that feeling of worthlessness.
"It was partly immaturity, partly the environment."
What Vincent, who has just turned 35, did not know, was that he was unwell. From the outside he looked great, as fit as a fiddle, but inside he was sick. He made a liar of that old mantra: healthy body, healthy mind.
So many elite cricketers, so many elite sportsmen and women, believe that to be true. As long as you're fit and healthy and active the mind will follow.
That theory falls short in science and logic, but it doesn't stop athletes believing it. Too often, though, it also stops them seeking help. They work on the theory you can train your way through it; that success on the field will filter through to all aspects of life.
It is, in many respects, the great athletic swindle.
Hugh Norriss, director of policy and development at the Mental Health Foundation, says a simple way to grasp the concept is that like physical health, everybody has mental health.
"We're all brought into this world and some of us are blessed with more physical attributes than others," Norriss says. "The current health orthodoxy is we try to live healthy lifestyles. We don't know who's going to get lung cancer, but we know it's a good idea not to smoke.
"Mental health is the same. People come with temperaments and they can be shaped over time but research shows we tend to go back to our set points, but we can learn."
There's a very clear and obvious difference, however, and that is that physical ailments, by and large, can be seen.
"Mental health is more difficult because it is more easily hidden. Like physical health you can't take it for granted, but that's what our culture does to an extent," Norriss says.
The MHF is promoting five ways to well-being, which is the condensing of a lot of research into simple concepts.
"These things give an immediate psychological boost because they balance up the positive to negative emotions but they also build resilience, because if you do struggle you've got something to fall back on.
"The Be Active one crosses over into that physical space. Being fit and physical exercise does boost positive emotions. It increases your confidence and there are various psychological boosts in there."
With something as simple as five key concepts, Vincent and several others who have endured similar mental health issues might have enjoyed longer, more fruitful professional sports careers.
Vincent was a jack-in-the-box type of character, but alone in any number of hotel rooms he lapsed into sports-jock cliche.
One of the indicators of mental health issues is addictions. Vincent is coy about his relationship with alcohol, but admits it became a crutch.
"For me, that was probably one of my biggest ... I wouldn't say I had an issue with it. It's like anything else with me, I can switch on and switch off. But you tend to rely on alcohol and, I don't feel comfortable saying the other things, to suppress the feelings of reality."
History has proved that few people make good decisions while on alcohol, or any other kind of stimulant. Vincent did nothing to disprove history.
"Eventually you start to seek a bit of company," he says, matter-of-factly. "That was my downfall. My weakness was the fact I had a partner at home but I needed some company tonight, I've met this person ... that's where I got into trouble and is a related factor for being divorced.
"I had to go through that to appreciate what a relationship is about and the feelings you leave behind when you've been unfaithful to someone.
"The temptations are there. There's alcohol. You have a bad day and there's a bit of built up aggression there, I bit of 'I don't care factor'. You think only about yourself and making yourself feel good.
"You wake up in the morning thinking 'that was stupid', and now I've got to live with that. Who can live in a relationship like that? It takes a pretty mentally tough person - if that's the right way of putting it - to live in a relationship for a long time while keeping secrets."
As it happens, that's the wrong way of putting it. Mental toughness might be about the most over-used compound in the sporting lexicon.
A better way of describing whether somebody has the right stuff to cope with the myriad issues high-performance sport throws up is mental health or mental wellness, not mental toughness. Vincent was pretty high on the scale of mental unhealthiness.
There were issues from his childhood that had never been resolved - he came from what he called "a dysfunctional" family - and an overwhelming sense of having never fitted in, something his rise to international cricket, and the cliques within the team, only exacerbated.
Adding to the pressure-cooker was fatherhood. What should have been the greatest joy of his life, a daughter, was a burden too big to bear.
Vincent lost his appetite. He couldn't sleep. When he did sleep he would curse the fact he had woken up.
"It's just the emptiness. There's a really big feeling of emptiness. You look at life and you go, 'This means nothing, absolutely nothing. Here's my child. Yeah, it's a good child. I'm supposed to love it but I don't want to love it because I don't want it to miss me when I'm gone.' You know what I mean?"
It was a friend who had seen Vincent's peaks and troughs that first mentioned he should seek help, and a fellow cricketer John Aiken, now a psychologist, who set him up with some coping mechanisms.
He took a call from Sir John Kirwan, too, that helped immeasurably.
"That gave me massive confidence to tell people what was happening with me," Vincent said.
Talking about it is, unsurprisingly, seen as the most important step, but it is the nature of the conversation that is most important. The conversation should not take place in hushed tones and behind closed doors.
"If you're not feeling mentally at your best you shouldn't see that as a moral failing and that's been such a strong narrative in our culture: the scorn and the stigma," Norriss says. "They are weak people who get stressed who just need to harden up and snap out of it."
Vincent, like many others, wanted to "harden up", he wanted desperately to "snap out of it". He just didn't have the tools. Just as pertinently, those who should have been looking out for him - his teammates and his coaches - didn't have the tools either.
Says the founder of the NZ Athletes Federation, Rob Nichol: "What we would like to see is a [high-performance sporting] environment that educates people how to monitor your teammates and your peers and how, when things are not quite going right, it's okay to put up your hand."
The series
Today: Lou Vincent's battle
Tomorrow: What is it about cricket and its unique pressures that led to some people labelling it the "suicide sport"? We talk to Iain O'Brien about his struggles.
Next week: Rugby's bold steps towards enlightenment and the "JK effect". The addictions hurting our sports stars the way forward.
Where to get help
• Lifeline - 0800 543 354 or (09) 5222 999 within Auckland
• Depression Helpline (8am to midnight) - 0800 111 757
• Healthline - 0800 611 116
• Youthline - 0800 376 633, free text 234
• Suicide Crisis Helpline - 0508 828 865
