Britney Spears' former bodyguard claims she was given a strong mix of prescription medication once a week.
Fernando Flores - who was hired to work for the Toxic hitmaker in 2010 but quit eight months later - told how the 39-year-old pop star's phone was monitored and she was banned from going out on her own, while visitors to her Los Angeles home had their bags searched.
The former policeman claimed a woman would call to the property every Friday to hand over medication.
He told The Sun newspaper: "I'd explain [to Britney] what everything was — three anti-psychotic medications and birth control pills.
"She'd go from sane to talking about parallel universes."
Fernando also told how Britney would be left in tears after being called multiple times a day by her father Jamie Spears, who is co-conservator of her financial affairs.
He added: "Jamie would call three or four times a day to check what was going on.
"If she wanted something, she had to ask his permission.
"She spent her days watching TV, or working out.
"When down, she'd cry listening to [James Brown's] It's A Man's World."
Last week, Britney broke down in tears during a court hearing and urged the judge to charge her father with "conservatorship abuse".
She said: "I'm here to get rid of my dad and charge him with conservatorship abuse. This conservatorship has allowed my dad to ruin my life."
The hearing also saw the Lucky singer - who has been under a conservatorship since 2008 - granted permission to hire former federal prosecutor Mathew Rosengart as her lawyer after her court-appointed attorney Sam Ingham recently stood down from representing her.
And as part of her new lawyer Mathew's first job on the case, he has said he will be filing a subsequent petition for Jamie to be removed and for Britney to end the conservatorship.
Last month, Britney claimed her conservatorship had left her "traumatised" and "depressed", and she called for her father Jamie to be jailed.
She said: "They have me going to therapy three times a week and to a psychiatrist.
"I truly believe this conservatorship is abusive. I don't feel like I can live a full life. In the meantime, I want this therapist to come to my home, I'm not willing to go to Westlake ... They set me up by sending me to the most exposed places. I need your help.
"My dad and anyone involved in this conservatorship, including my management … they should be in jail."
Following the comments, Jamie's legal team released a statement which read: "He is sorry to see is daughter suffering and in so much pain. Mr Spears loves his daughter very much."
Afterwards, a judge denied Britney's request for her father to be suspended as co-conservator.