The group published a statement on their official Facebook page on Wednesday 25 March confirming that Zayn had quit the group. The message from Malik read:
"My life with One Direction has been more than I could ever have imagined. But, after five years, I feel like it is now the right time for me to leave the band. I'd like to apologise to the fans if I've let anyone down, but I have to do what feels right in my heart.
"I am leaving because I want to be a normal 22-year-old who is able to relax and have some private time out of the spotlight. I know I have four friends for life in Louis, Liam, Harry and Niall. I know they will continue to be the best band in the world."
Less than a week earlier Malik's publicist, Simon Jones, had revealed that he would be flying home from the One Direction tour.
He tweeted: "Zayn has signed off with stress and is flying back to the UK to recuperate. The band wish him well and will continue with their performances in Manila and Jakarta."
Stress is something we all deal with in our daily lives - be it caused by our work, personal lives or world events, and many One Direction fans are currently feeling under stress after learning of Malik's departure. But what does it actually mean to be stressed?
"Think of a bridge. Then start imagining adding lots of weight onto that bridge – double-deckers, trucks, cargo ships, planes and helicopters. Maybe even a tank or two. If you put enough weight on the bridge, what will happen?
"That's right, it will start to buckle and groan and creek and eventually collapse. If you put enough demand on a person, they too, will collapse like the bridge.
"Just like Zayn, stress can affect everyone. No matter of age, sex, career, financial status – if the demand exceeds the person's resources, the person will experience burn out."
What does it take for somebody to be signed off work with stress?
According to Dr Pablo Vandenabeele, Bupa’s clinical director for mental health, there is no simple answer.
"The levels of stress required before someone has to go off sick from work differs greatly between individuals (depending on their stress resilience) but also can vary between different times in a person's life," he explains. "The important factor is the impact the stress has upon someone's mental and physical health."
Is stress serious?
"We have to take this seriously as stress undoubtedly makes people ill," says Shah. "Indeed, the top killers on the planet have been linked to stress (heart disease, cancer, stroke, and adult-onset type-2 diabetes).
"Chronic stress can also lead to back problems, heart problems, migraine, asthma, digestive problems, skin conditions and allergies. If you stay in this state for a prolonged period it can also lead to poor mental health. Stress, anxiety and depression, are the reason for one in five visits to a GP (according to NHS Choices) so we really need to start understanding and recognising stress in order to start dealing with the problem."
What are the signs that someone is suffering from stress?
"Changes in sleep patterns and appetite, irritability, impaired concentration and even physical symptoms, such as palpiations and increased blood pressure, suggest there might be a problem," says Vandenabeele. "These symptoms are not necessarily a cause of concern, but if they last for weeks, the alarm bells should be ringing."
What should you do if you are suffering from stress?
“If you identify the problem in time then you may be able to tackle it yourself through prioritising tasks, exercise, and techniques such as mindfulness and meditation," says Vandenabeele. "However, if your symptoms last for more than a couple of weeks then it’s important that you seek help and see a GP.”
Here are some quick and easy ways to prevent and relieve stress from The Stress Management Society:
1) Avoid nicotine, alcohol, caffeine and refined sugar products.
They are all stimulants, so therefore they cannot calm you down. If you're stressed, steer clear of them and keep yourself well-hydrated by drinking water instead.
2) Work off stress with physical activity.
Pressure or anger releases adrenaline in the body. Exercise helps to reduce it, and produces 'good mood' substances in the brain. So go for a brisk walk around the block when you feel tense and try some regular exercise after work.
3) Get enough sleep.
Sleep is essential for the body to function properly. Create a bed time routine where you do not stimulate your body and mind for at least an hour before sleep.
4) If you're ill, rest.
Don't just carry on regardless. Working will tire the body and prolong the illness. So recognise that you have limits and don’t carry on as if you were firing on all cylinders.