A young man felt as though he was a "waste of space" before being diagnosed with a lifelong condition that had been missed since childhood.
Josh Beale, 23, spent years struggling to focus and stay awake in class, with mood swings and an overall feeling of being unstable.
He initially dismissed the idea of having attention deficit hyperactivity disorder (ADHD) and chose to pay for a private diagnosis.
But the psychiatrist only confirmed that he had the condition which came as "an absolute revelation" for Josh.
Looking back, Josh, from Wirral, Merseyside, said he felt "there's obviously something wrong" and wondered why nobody had spotted his condition sooner.
He told the Liverpool Echo how he would feel great one day and terrible the next, forcing him to resit his second year of university.
"I couldn't keep up, I couldn't look after myself and I wasn't really eating. I didn't actually stay awake in a lecture until my third year of uni," he added.
Josh said he could not remember the last time he was happy and fell into a "vicious cycle" of anxiety about not meeting his expectations which made his focus even worse.
Cognitive behavioural therapy did not help despite his efforts to set a routing and improve his sleep and eating habits.
"People would say 'oh have you done the work for this seminar?' and I'd say, 'ooh what am I like, I haven't done it' just laughing it off," Josh said.
"When really, on the inside, I was like 'stupid boy, I can't believe you forgot to do that. That's so annoying, you're such an idiot. You're such a waste of space'."
Josh said his idea of what ADHD was did not match his behaviour and he was shocked by his diagnosis.
He explained: "My stereotype and image of what ADHD was didn't really compute with my view of myself.
"My idea was a little boy distracted by anything, who can't sit still and always struggles to focus."
ADHD affects the ability to plan, problem solve and self regulate emotions.
The neurodevelopmental disorder can affect how people experience emotions and time, how they organise their thoughts and manage impulses.
It is also linked with strengths like creativity and an ability to 'hyperfocus' on compelling or urgent tasks.
How it presents varies from person to person, meaning it is often missed in people who don't fit the popular image of ADHD.
This is more so the case in women and girls than men and boys, as the condition often presents differently between sexes.
People with ADHD are more likely than the general population to have mental health conditions like anxiety, depression, or substance abuse.
This is often caused by the negative self-image people with ADHD may have of themselves, stemming from failing to meet deadlines, remember obligations or follow instructions.
This can be even worse when the person has no diagnosis or understanding of how their brain works.
Learning about ADHD in a neuroscience module "hit close to home" for Josh and sent him on a path to diagnosis.
Not wanting to repeat another year or drop out of university while on an NHS waiting list for up to six years, he chose to pay for a private psychiatrist who diagnosed him with the condition.
He said it was "an absolute revelation" when he started medication for ADHD two weeks later and stayed awake for an entire lecture for the first time.
It took a year to find the dosage that best regulates his emotions, attention and sleep, but he could still be waiting for assessment and treatment if he went through the NHS.
Patients should wait no longer than 18 weeks from a GP referral to the start of treatment according to the NHS Constitution.
Under 'Right to Choose', the NHS will pay for private providers to treat patients if NHS waiting lists are longer than 18 weeks.
But with an estimated 1.5m adults in the UK having ADHD, only 120,000 of which are diagnosed, pressure is building on services.
'Right to Choose' appointments at Psychiatry UK are booked until October 2022, and it takes up to six months between an initial assessment and the start of treatment, according to the private psychiatry service's website.
Josh, who manages the Liverpool-based ADHD Foundation's Umbrella Project, said: "The current system feels unfair, appears to lack efficiency and I'm not sure it's sustainable."
A spokesperson for Mersey Care NHS Foundation Trust, which provides specialist adult ADHD services, said: "Mersey Care prides itself on being a learning organisation and, as such, constantly reviews our services and how we can improve them.
"We are currently recruiting to expand our ADHD services to enable provision of additional assessments, which we expect to have a positive impact on the patient experience in the coming months."
