The walls are closing in on me. The air is sucked out of my lungs and everything turns black. One thought pulses through my mind - to get out of the room, no matter how. I push open my window and start climbing out. Only when the fresh air hits me do I realise something's not right. I fall backwards and crawl back into bed, confused and disorientated by my surroundings.
This was the most dangerous night terror I suffered during my final year at university. I initially forgot what had happened, until I saw the chaos the next morning - my desk and chair were overturned, my books had been knocked off my bedside table and my laptop's screen had smashed. The window was still wide open.
Deep bruises came up a day after, with the right-hand side of my body turning black and blue. My GP practically laughed me out of the surgery when I went in for a consultation. "There's nothing I can do about it, it happens in your sleep," he said, smiling. It was only once I had moved to London and suffered a similar attack that left me bleeding that I decided I'd had enough. After a three-month wait, I finally managed to get a space in one of the UK's busiest sleep clinics for an overnight study.
The technicians wired me up at the clinic at London Bridge. There were 10 sensors attached to my head alone, with countless cables running down my body. Lying on the bed, monitored by two cameras, I knew that I wouldn't be having a night terror that night. But I was hopeful that the results might shed some light on my condition.
When someone suffers from a night terror, they can scream, shout and thrash around in extreme panic, sometimes jumping out of bed. It's an unnerving experience for anyone to watch - the sufferer's eyes will be open, but they're not fully awake or aware of what they're doing. Once the panic subsides, the person will fall back asleep, oblivious to the chaos.
Most people experience nightmares or night terrors growing up. Figures show that between 20 and 30 per cent of children between the ages of five and 12 have frequent nightmares, while night terrors affect 17 per cent of children. Once children reach adulthood, incidence rates are much lower, with only one in 20 of that 17 per cent still reporting night terrors in later life. But recent research has linked recurring night-time problems to more ominous long-term consequences. A study conducted by the University of Warwick followed nearly 6,800 children up to the age of 12. The results suggest that long-term sufferers of nightmares and night terrors have a higher risk of mental health problems as they enter adolescence. Those having nightmares aged 12 were three-and-a-half times more likely to have problems and the risk was nearly doubled by regular night terrors.
Psychology professor Dieter Wolke led the research at Warwick. He says that while children often experience night-time problems, in adults, it's only around 1 to 2 per cent who still have night terrors. When they persist into adulthood, the physical risks also increase. "Night terrors become more dangerous, as you're larger and more mobile. People are known to have fallen off balconies or thrown themselves out of windows," says Professor Wolke.
From a young age, I have been a restless sleeper, but the night terrors only started happening when I entered my teens. It wasn't until university that they became more severe. The more extreme ones saw me running around the house or frantically trying to open my bedroom window.
So why do night terrors occur? According to Dr Nicholas Oscroft, a respiratory physician at Papworth Hospital, genetics and not getting enough sleep could be to blame. "It does seem to run in families... From previous research it has become clear that night terrors happen more often if people don't get enough sleep on a regular basis. Work or family-related stress also increases the risk."
Another sufferer is 24-year-old Kevin Stone. He started having night terrors from the age of seven. He believes it's because of having lived in South Africa, where his family experienced regular break-ins. His night terrors follow a repeated theme - someone is always trying to chase or kill him. "I once dreamt that people had broken into the house and were in my room. They made me get out of bed and kneel on the floor while I tried to convince them not to kill me. When I have a night terror, I act out everything. I can hear their voices, I can see them, I can even feel the gun against my head."
Stone's night terrors took a gruesome turn when he was 18. One night, he woke up and was convinced someone had broken into the house. As a result, he jumped out of his bedroom window and fractured his spine and broke both his ankles. "I realised what I was doing just before I hit the ground." Terrified by what his sleeping mind was capable of, he sought treatment to stop his night terrors from happening. But he believes that his problems can't be solved, because it's all in his mind. "Doctors have said to keep a bedtime journal to clear my mind, but that hasn't worked." He also wasn't happy with the option of being prescribed antidepressants.
So can night terrors be solved? Dr Oscroft seems unsure. "Adult patients who suffer from them need to try and reduce how often it happens. The best way to achieve this is by getting enough sleep. People should also optimise their sleeping environment, so that they won't be woken up during the first two hours of sleep, which is when night terrors are most likely to occur."
Night terrors can put a strain on relationships. Dr Oscroft says the best thing to do when someone is suffering from a night terror is to reassure them. "People who are having a night terror will be agitated, so the best thing to do is to calmly talk to them until they wake up. Don't try to restrain them unless they are in danger of hurting themselves."
My results from the sleep clinic proved surprising. I had woken up four times during the night - flustered and disorientated. Even though there was no physical cause, I do suffer from slow wave arousal disorder, which is usually associated with sleepwalking and other sleeping disorders. Aside from the advice to sleep more or to take sleeping pills, my diagnosis remains unchanged. I suspect that it will be something I'll have to deal with on a regular basis throughout my life. Until they stop completely, I'll be keeping my bedroom window firmly locked.