Workplace stress drove a solicitor to a dependency on strong painkillers in a bid to tackle burnout, she has said.
At her lowest point, Lara Cox, 33, would take up to 12 codeine tablets daily and "couldn't go a day without feeling ill".
Burnout is recognised by the World Health Organization as a state of physical and emotional exhaustion.
Ms Cox, from Porthcawl, Bridgend county, said she was left feeling isolated and her situation even affected her eating habits.
The Wales Trade Union Congress (TUC) said work-related stress had resulted in more people using alcohol and prescription drugs.
Ms Cox said: "There’s a societal expectation to strive to get ahead and an emphasis on being a 'girl boss' and the so-called 'hustle culture'.
"That’s fine if you want that, but I think it takes a lot for someone to say actually 'this isn’t for me'."
After taking a senior role in the financial sector, she said she no longer had a work-life balance.
"It was nothing to do with the company, it was how I managed the stress - it was overwhelming," she told Wales Live.
Lara said she felt isolated and lonely with the stigma around speaking out about the issue.
She said making a change to her role at work lessened some of the pressures, and her employers were supportive and understanding.
General Secretary of the Wales TUC, Shavanah Taj, said: "Workers are telling us that because of stress and burnout, they're turning to alcohol and prescription drugs just to be able to cope with day-to-day life."
She added that others had turned to gambling as a way of trying to make money and the burden was often bigger on women as childcare an caring responsibilities often fell on them.
In January 2023, the Wales TUC called for flexible working arrangements for all employees.
"If we want healthy, inclusive workplaces, then we have to be more flexible. We have to understand that if you want to get the best out of your work force then we need to have measures in place where work-life balance is a reality," Ms Taj added.
Dr Liza Thomas-Emrus is the lead clinician for the Wellness Improvement Service (WISE) at Cwm Taf Morgannwg health board.
She said burnout was a "huge issue" and should not be confused with stress.
"Burnout is mainly related to workplace stress which is sustained and prolonged that becomes unresolved. We’re all at risk from it.
"It’s very common for people to initially try and find quick and easy options like drinking more alcohol or taking pharmaceuticals, but unfortunately that doesn’t resolve anything."
Dr Thomas-Emrus said the key areas the WISE service was focused on improving was people's sleep, social connection and relationships, nutrition, exercise, minimising harmful substances and mental health.
She said making positive changes could be overwhelming for those struggling with burnout, but the first step was to recognise it and be willing to ask for help.
The Welsh government said it was working with employers and trade unions to promote conditions that provide work-life balance and tackle stress and burnout.