If you feel the earth's pain before an earthquake or have a panic attack because someone near you is anxious, you might be an empath too.

If you search for any article about "empaths", you'll find it has thousands of likes and hundreds of shares on Facebook, and in the comments, dozens of people claiming to be an empath themselves. Underneath "30 reasons you could be an empath" or "6 grounding tips for empaths and highly sensitives", people lament the fact they were born an empath, welcome other newly realised empaths to the fold – or, in the case of one commenter, note that, "One of the hardest things about being an empath is learning not everyone is." But what is an empath, and why are so many people across the world convinced that they are one?

In short, empaths claim to feel other people's "stuff" as if it's their own. Many people will never know they are one because they find it difficult to distinguish between their own physical ailments, or thoughts and emotions, and those belonging to someone else. If unchecked, one consequence may be that your life is unconsciously influenced by others' desires, wishes, thoughts and moods.

Caroline Van Kimmenade, who runs courses for empaths who want to understand their power and live their best life, compares this transfer of energy to something we can all experience. "It's like a football match where everyone gets hyped up and starts waving and then the mob things start sweeping you up and you barely know you're doing it," she explains. "We can all experience that but it doesn't mean you're an empath. But for an empath it's that multiplied and applied to everything all of the time. Empaths are constantly in a giant football stadium where they're reacting to bigger things going on from all directions."

When 29-year-old Siobhan from Las Vegas was younger, she'd randomly get aches and pains she couldn't explain. She was diagnosed with depression and anxiety and had terrible panic attacks. Her mood swings were so bad that a doctor thought she was bipolar. But she was convinced it was more than just a mental illness – these moodswings and pains were linked to other people. "If I got a neck or shoulder ache, I'd know someone was stressed out. I'd text around to find out where it was coming from and someone close to me would tell me they were feeling awful. When my husband was worried about something, I could go up to him and say 'What's bothering you?' and he'd eventually tell me and it'd be something wrong."

One day she read a piece online – "31 traits that show you're an empath" – and completely identified with it. "I could relate to almost all the characteristics. It was so good to find out I'm not always moody, or bitchy, like there's a reason, I'm picking up someone else's energy."

Every article on empaths will tell you it's different to the sensation of feeling compassion or empathy for someone who is hurting. As an empath, you feel things as strongly as if they were your own. Complete strangers will want to unload on empaths about personal things as if, on a subconscious level, that person knows the empath will listen with compassion and understanding. It can be draining.

Some people believe there are loose types of empath within the broad definition. Emotional empaths pick up on emotion energies. For them, shopping during Black Friday, for example, would be overwhelming. A physical empath picks up on the physical ailments of other people. In a hospital, or with an ill partner, they might start getting nauseous or a headache or something similar. Animal empaths feel the emotions of animals, feeling trapped or stressed walking near a zoo. If you're a global empath you pick up on the feelings of humans across the planet, rather than just a specific person. Even if you don't watch the news, you'd feel the stress of a global catastrophe – an earthquake in another country might cause you to feel alone or anxious. An earth empath will feel feelings or sensations that relate to the planet's energy. If a major earthquake is coming, they'll feel it beforehand with muscle spasms, headaches or stress that passes once the event has taken place. Most empaths are generally thought to be emotional or physical empaths; however, they can be a mix of any or all of those types.

With all those potential triggers, the modern world is a challenge. Vix Maxwell, 36, was working as a teacher in London when she realised she was an empath. The energy from both the job and the city was difficult. "I'd be sitting around in the staffroom surrounded by people bitching and you can't engage in a conversation without finding yourself going into that energy. I noticed a huge difference as soon as I entered and left work. I actually found the kids' energy was not as bad as the older people I worked with. I started to wonder if I had a split personality because I was so upbeat and happy and in other situations or with certain people I was a polar opposite."

She did research into what an empath was and learnt ways to help her deal with her environment from others who identify with that label. "I would sit in the car before I went into work and visualise myself in a protective bubble and say, 'My energy is protected, nothing can come in that's not mine.' It made such a difference. I'd go into the toilet if I started feeling too many people's energies during the day and stand there and say 'I'm protected, I'm protected' and it really made a difference."

Eventually she had to quit. "As soon as I started realising what was my energy and what was other people's – and protected what was mine – I was able to connect with what I wanted. I started a blog about energy and now do tarot readings." She also left London for a quieter place. "It's like an empath's worst nightmare being on the tube," she laughed. "It's honestly part of the reason I had to leave. I'd repeat mantras like 'I'm protected' and if I go on there now for work I try to visualise white light or hearts above everyone's head to send them love to remember that people are all connected and we're all in the same boat."

The difficult part of this whole journey, according to Caroline, is working out whether you are an empath or not. "Some people are just extremely emotional people themselves or have a lot of trauma they have to deal with. It can be easy to feel like these overwhelming emotions are not your own because we live in a world where emotions can feel very foreign." She advises to test whether you feel markedly different around a very negative person or someone with extreme ideas. "Sometimes I will do this long-distance energy healing with someone and if someone is an empath I'll find there's all this energy from other people in their system and that's clear proof."

Once you know you're an empath, the women report a sense of relief at having the tools to deal with it. "Growing up as an empath, you can sometimes lack a sense of identity, so as you do meditation and shielding (the bubble exercise, for example, as described by Vix) you start to understand yourself and know what your purpose is," Siobhan explained. "I don't have mood swings anymore. My husband notices it. Now I can read my own emotions and others' separately and literally feel the sadness and irritation come into your aura." Like Vix turning to tarot readings, empaths say they can use their perceived weakness as a strength. "Since I was really little I've been massaging people and my husband has always loved my massages," says Siobhan. "So I looked into learning reiki (energy healing) and the first time I did it it was mindblowing. After that I healed two headaches just by visualising. That was only at the beginning of learning and now I've been doing it a while."

Obviously, this whole concept falls into the realm of new age philosophy. It's not exactly diagnosable by a doctor and if you went to a mental health specialist to tell them you physically feel the world's pain, they'd be concerned. Caroline is aware of this. "There is a lot of people who are in this psychic realm who are just suffering and also sometimes have mental illness," she says. On her website it clearly states that her services are not for those with a mental illness and she isn't a licensed mental health practitioner. Often, she says, this becomes very blurred with what being an empath is.

Caroline was working on a PhD at the time she realised she was an empath and was very concerned about what people would think when she started exploring what this meant. "I was so worried about being branded a crazy. There was a spiritual workshop I attended while still working at my university job. At a certain point, a guy came in with a camera. He was meant to take some photos of our little workshop group for their spiritual centre website. I literally ran off and locked myself into the bathroom, refusing to come out until they promised I wouldn't be in any pictures. I was really worried that exploring energy healing would make me lose credibility at work, so I didn't want anyone to find out about it."

"Ironically, in the end, my academic training really helped me find my way through all kinds of healing modalities. Spiritual communities tend to be on the 'just believe' end of the spectrum. There is often little tolerance for testing a hypothesis or making up your own mind. People are quick to point fingers and say you don't have faith or don't trust enough. I really felt supported by my academic background though in asking tough questions, being critical and trying new things. I tended to be that 'annoying person who always had too many difficult questions'. Without that, I don't think I'd have been able to learn what I needed to learn about being an empath, and how that works."

Just because it exists outside western schools of thought, doesn't necessarily mean it's not true. Some research suggests that one in five people is a Highly Sensitive Person (HSP), a clinically recognised condition. Rather than just being a personality type, like being shy or outgoing, HSPs are defined by their hypersensitive nervous system. Besides easily being overwhelmed by emotional things and having incredible empathy, HSPs also have a heightened sensitivity to physical things like lights, sounds and temperatures. It's widely agreed in the empath community that most empaths are HSPs, but not all HSPs are empaths.

Until then, Caroline advises field tests, if this resonates with you. "Think you're picking something up from someone else? Subtly ask them about it, as in: 'Hey, you're looking a little pale... are you feeling alright?' When you feel something and suspect it's not you, and then someone around you confirms that they are actually feeling that way, that's great validation. It helps you take yourself more seriously. You need to be the one who comes to terms with this being a real thing - or, discover that perhaps it isn't and it's just your own feelings. You have to field test this. Track your intuitive insights: what was your sense about someone, and what happened with that person over time? When you do this, you'll start to see the areas where there is more going on than just you feeling your own feelings. It's hard as a rational western person to open up to this idea and there's often a fear. But you don't need to be scared any more."