Seeing your child shackled to a bed in a foreign country might seem like any parent's worst nightmare. But for Ros Morris, it is just one in a long list of harrowing experiences she has been through with her son, Zach.
Diagnosed with bipolar disease, in which sufferers experience episodes of both mania and depression, Zach, now 29, has also been heavily addicted to a variety of drugs, including heroin.
Now his mother has written a book in which she describes the events surrounding his illness and drug abuse, from when he had his first psychotic episode 11 years ago, aged 18. She has changed her son's name to protect his identity.
Throughout her book, Don't Wait For Me, Morris, 57, is brutally honest, admitting at times that she hates her son and cannot bear to be around him.
"Sometimes he turns into a complete monster, and I hate him when he is like that. It is horrible and repulsive," she says.
But such feelings are difficult to deal with. "I feel very guilty for feeling that way. It is very sad and depressing and not the kind of thing you want to feel about your child. When he is well, he is a very bright, charming, articulate, creative person. But when he is not, he is someone you do not want to be around," she explains.
One of the main frustrations for Morris is that her son has always been reluctant to take the medication prescribed for his condition, meaning he is "worse than he could be if he took it".
Ros Morris, a sculptor and writer who also worked as a researcher for the Imperial War Museum's Holocaust exhibition, wrote the book in order to help others in a similar situation.
"When Zach was diagnosed, I looked for memoirs of people who had been through something similar, but could not find anything. It felt very isolating," she says. "Zach is OK about me writing it, but he won't read it as he would find it too painful."
In the book, she recounts a number of traumatic events that occurred over the past 11 years. In 1998, Zach was hospitalised in Athens, Greece, after being arrested while travelling. His mother was called to fetch him, and walked in to find him shackled to a metal bed.
"I was so angry. I had never felt such rage," she says. "He had been beaten up and had cuts and sores all over him and he had been chained to the bed. It was awful."
But she says that was not even the lowest point. The worst time was last year, when Zach became "grandiosely manic".
While in travelling in Thailand, he was using drugs. He found himself in trouble at one of the country's borders. After having his passport confiscated, he was imprisoned before being placed in a psychiatric hospital.
"We had actually said to him before he went that if he got in trouble again abroad, we would not help him any more. But of course we did," Morris says.
She contacted the Lubavitch office in Thailand and some of its representatives went to visit her son. They reported back to his parents - Ros and her husband Tony, 56 - with shocking news. "They said, ‘He is going to die in there'. He had been put in a cage with 100 other very distressed people," she recalls. By the time the Morrises arrived, the Lubavitch representatives had managed to get Zach into a private room.
His parents brought their son back to the UK, where his mother says he deteriorated and refused to go into hospital. At the same time, he became addicted to heroin. Whilst living in a flat in Primrose Hill, North London, which his parents had bought for him, the situation worsened. "He became sicker and sicker. He almost died because he was so badly addicted to heroin. He began taking in homeless people and junkies and the flat was completely destroyed, so we had to throw him out, and he was living on the streets for a while."
That was not the only time Morris had to throw out her son. By the time he was 22, Zach's parents no longer felt able to live with him.
"He was intent on self-destruction and he was destroying us. We couldn't live with him any more, but it was very difficult to throw him out," his mother explains.
The family then moved from their house in Golders Green to a smaller house in Hampstead in which there was no bedroom for Zach, but his parents helped him to pay for rent in a shared flat.
A constant theme over the past 11 years has been Zach's anger towards his mother. He has repeatedly told her that he does not wish to have a relationship with her. "It is devastating when he says those things," she admits. "But he has always said them when he has been ill so I try to dismiss it, but it does tug at the heartstrings."
There have been times when Zach's anger towards his mother has been so severe that he has lashed out. "I have felt scared for my own safety at times," Morris admits. "He has thumped and pushed me a couple of times."
The effect on her family has also been extreme. In the book, she recounts one occasion when her husband Tony, a lawyer, collapsed in floods of tears, exasperated at Zach's behaviour.
"It was heartbreaking seeing him like that," she recalls. "It put a strain on our marriage, but eventually we had to make a decision not to allow it to ruin our relationship."
However, the person most affected, according to Morris, has been Zach's sister Jessica, a 26-year-old photographer. "She used to be very close to her brother, but now she's insecure with him as she is never sure how he will relate to her and he has been quite aggressive towards her. So she keeps her distance now."
Looking back over the past 11 years, what is Ros Morris's advice to others in a similar situation? "Most importantly, if you think your child has a drug problem, you have to go through all their things to see if they have drugs. If they do, you must be tough," she says.
Her turning point, she says, was when Zach was arrested last year for being in possession of drugs and a knife. "It was the best thing for him. He had to spend a night in a police cell and it taught him a lesson."
So for now, although Zach is stable and off medication, his mother lives with "the constant fear that he might deteriorate and something might happen again".
Don't Wait For Me is published by Mainstream at £6.99