Stacey Talley told the programme that she and her partner were told they had to go on the show despite changing their minds, while Dwayne Davidson accused producers of creating tension behind the scenes by keeping him in isolation for hours.
One former producer, speaking anonymously, told the programme: “Researchers and (assistant producers) and sometimes producers would smoke weed with guests in the hotels the day before to keep them happy.
“If guests were becoming flakey they’d appease them in any way they could.
“There was a contributor who was a drug addict and had since stopped taking drugs and cleaned their act up.
“But in actual fact the show wanted them to be on drugs, because there was no ‘story’ without it. One of the producers was asked ‘get that person to take drugs again’ and at one point was asked ‘leave money lying around on a table so they will take that money and go and buy drugs with it’.”
A producer who made a behind-the-scenes documentary about the show: “When I was filming backstage in the corridor, I would see cans of lager mainly going backwards and forwards, either being passed between researchers and heading to the dressing rooms or coming through on trays.
“I asked who it was going to and they said it was going to the contributors who were appearing on the show.”
ITV said claims the producers had taken drugs, forced addicts to take drugs or encouraged the use of taxis to collect drugs were “untrue”.
A spokesman added: “ITV would never condone Illegal drug taking.”
Alcohol was also banned in the study, the spokesman said, adding: “The only exception is in relation to a small number of guests who are going on to a residential rehabilitation programme after their appearance on the show.”
It was claimed Ms Talley had been offered relationship counselling and was offered additional counselling following her suicide attempt, while ITV refuted the suggestion Mr Davidson had been locked in a dressing room.