WHEN I was asked to write this article, my heart started beating faster, my hands started shaking and my thoughts went into overdrive coming up with what felt like hundreds of objectively sensible reasons why I couldn鈥檛 do it. I could tell you that as chief subeditor at 快猫短视频 I don鈥檛 often get a chance to write. But the truth is I rarely write because I am very anxious about it. What if the people I contact don鈥檛 respond? What if I write something stupid? What if I am stupid? What if, what if, what if.
Clearly, I chose to write this article, partly because I am stubborn and hate that these anxious feelings hold me back from doing things I might enjoy, and partly because I find that doing the things that make me anxious helps me overcome that feeling (see 鈥淔ive scientific ways to help reduce feelings of anxiety鈥�). But my main motivation was to answer questions that have been bothering me for years: what exactly is anxiety and what is happening in my body and brain to cause this feeling?
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Answering that first question is difficult, in part because there is no one way to feel anxious. 鈥淚鈥檇 say there鈥檚 as many types of anxiety as there are people in the world,鈥� says , head of the Anxiety Lab at University College London.
We do know everyone experiences anxiety 鈥� it helps prime us to be ready in possibly risky situations. Consider walking home alone in the dark, where that feeling of being on edge and alert may help you to react if the unexpected happens. Where it becomes more of a problem is if you still feel like that when you are safe at home. 鈥淎nxiety is a threat response in the absence of a threat-inducing stimulus,鈥� says at the Laureate Institute for Brain Research in Tulsa, Oklahoma.
We don鈥檛 know exactly what is happening in the brain when you are anxious, says Robinson. However, one area that has had a lot of attention is the amygdala, as it deals with fear-related memories and is involved in detecting danger and helping conjure involuntary emotional responses.
When it has picked up a potential external threat, the , the region at the front of the brain that deals with complex functions like emotional regulation. Then, two sections of this region step in: either the tells the amygdala to pay attention to these signals or the ventromedial prefrontal cortex dampens them. We think that, in an anxiety disorder, this normally helpful process goes awry, so that you experience anxiety at inappropriate times or too intensely, says Robinson (See 鈥淎nxiety vs anxiety disorders鈥�, below).
But potential threats that spark anxiety don鈥檛 only come from external sources. 鈥淭here could be a change within your body and you then have a threat perception,鈥� says Khalsa. This is due to something called interoception. Often referred to as our sixth sense, interoception is how our brain keeps tabs on what is happening within the body, subconsciously monitoring things like muscle tension and carbon dioxide levels in the blood. 鈥淥ftentimes, anxiety is a misinterpretation of a [physiological] signal,鈥� says Khalsa. Becoming aware of a change in heart rate, for example, could induce anxiety by making you think you are having a heart attack.
Evidence that higher interoceptive awareness may contribute to feelings of anxiety came when 24 women with generalised anxiety disorder (GAD) were given 0.5 micrograms of the drug isoproterenol to increase their heart rates. They experienced , thought to be a measure of cardiac interoception, than 24 controls without the condition. Prior to taking isoproterenol, the women with GAD also had a higher measure of cardiac interoception than the control group.
Given anxiety seems to depend on this connection between mind and body, where does the initial trigger start, in the brain or in the body? 鈥淲e don鈥檛 know,鈥� says Khalsa. 鈥淪ome would say that the two are happening simultaneously. It is close enough in time that, for all intents and purposes, it doesn鈥檛 matter.鈥� What seems clear is that both parts play a role in anxiety. 鈥淚f you think about it in evolutionary terms, having this feedback loop is probably useful, because it means that you鈥檙e able to adapt and update your perceptions,鈥� he says.
So, did learning about what happens when I feel anxious help when writing this article? A little. I have no plans to switch careers, but the next time I am asked to write about something I am interested in, I plan to take control of my overactive anxiety response and say yes without hesitating.
Anxiety vs anxiety disorders
Anxiety is a feeling of fear or unease that is often accompanied by physical symptoms, such as sweating or a rapid heartbeat. While being anxious can be a normal response to stressful situations, when this emotion is triggered excessively, becomes difficult to control or is felt without a specific cause, it may be symptomatic of an anxiety disorder. These include a variety of conditions, such as phobias, social anxiety disorder and generalised anxiety disorder, and their effect on a person's life can be debilitating. Around and . Bethan Ackerley
Why did anxiety evolve?
Given that feeling anxious is a universal part of being human, it must have evolved for a reason. The most established idea is that it was to help us look out for danger, in particular to avoid the predators that would have hunted our ancestors. By being anxious about the prospect of meeting a big cat, for example, our ancestors may have adapted their behaviour, such as travelling in groups, to increase their chance of survival and having offspring.
This suggests that anxiety may be felt by all prey animals. However, it is hard to tell whether an animal is feeling anxious. In humans, the only way to know for sure is to ask 鈥� and we can't do this with animals. Instead, we can see if their behaviour resembles that of a human who feels anxious, says Sahib Khalsa at the Laureate Institute for Brain Research in Tulsa, Oklahoma. Mice, , and , among others, are all thought to exhibit behaviours related to anxiety.
However, Jeffrey Mermelstein, a psychologist based in Albuquerque, New Mexico, thinks there is a second aspect to the evolution of anxiety in humans. He suggests that another form of anxiety evolved from our predator fear response 鈥� a 鈥� leaving us with two broad types of anxiety. EP
