Having a sense of impending danger, panic or doom
Having an increased heart rate
Breathing rapidly (hyperventilation)
Feeling weak or tired
Anxiety and its associated disorders represent the most common form of officially classified mental illness in the United States today, more common even than depression and other mood disorders. According to the National Institute of Mental Health, some 40 million American adults, about one in six, are suffering from some kind of anxiety disorder at any given time; based on the most recent data from the Department of Health and Human Services, their treatment accounts for more than a quarter of all spending on mental-health care.
I think simply acknowledging having anxiety, addressing the physical and emotional ramifications, being able to sit with it and realize this is happening has helped me, rather than to react with real fight or flight. Then I address it: this is how you're feeling, you're okay, it's part of anxiety, breathe. Once I calm down a bit I do something that makes me feel comfortable. A walk, continued breathing, talking myself down. I think Cognitive Behavioral Therapy has helped a lot.
No one wants to be diagnosed with anxiety disorder, but by the time I finally went to a doctor to talk about these weird episodes I was having, I was so relieved to find out that I wasn't just losing it! I was having occasional panic attacks and an underlying unease that just wasn't going away. A low dose of an anti-anxiety drug has kept the panic attacks away for 15 years. I still get anxious at time, but it is manageable.
Another author I can't recommend highly enough would be Claire Weekes. She specialized in desensitization techniques and discussed the idea of 'first fear, second fear' - namely, that something in your environment triggers a 'first fear', which in your mind triggers the 'second fear' which is nothing more than a reaction to the first fear, which results in a vicious cycle that can trigger panic attacks. As someone who suffered severe panic attacks in adolescence, these books did more for me than years and years of therapy and medication ever could. It gave me the tools to help myself get better. The desire to 'get better' and survive, combined with Dr. Weekes' work, is the reason why I'm still alive today.
Finnish scientists have identified genes that may predispose to anxiety disorders. Research conducted under the supervision of Academy Research Fellow Iiris Hovatta have focused on genes that influence human behaviour, and some of the studied genes show a statistical association with specific anxiety disorders.
What makes the business even more confusing is that anxiety is hard to distinguish clinically from depression. We picture anxious people as hyper and overreactive, and depressed people as lethargic and indifferent. But depression, too, can be understood as a response to a perceived or imagined threat, and antidepressants like Prozac and Effexor also alleviate anxiety. Medically, anxiety and depression appear to be two related symptom clusters arising from (or causing) the same underlying neurological condition. So melancholy, grief, abulia, Weltschmerz, loss of libido, thoughts of suicide, and, presumably, a host of other symptoms associated with depression, like anger and irritability, all get lumped into the category of anxiety.