It's important to note that everyone feels anxiety to some degree regularly throughout their life - fear and anxiety are adaptive and helpful emotions that can function to help us notice danger or threat, keep us safe, and help us adapt to the environment. Anxiety disorders represent states when fear or anxiety becomes severe or extreme, to the extent that it causes an individual significant distress, or impairs their ability to function in important facets of life such as work, school, or relationships. It is also important that risk factors don't at all imply that anxiety is anyone's fault; anxiety disorders are a very common difficulty that people experience. In this section, we will review risk factors for anxiety disorders. There are many potential risk factors for anxiety disorders, and most people likely experience multiple different combinations of risk factors, such as neurobiological factors, genetic markers, environmental factors, and life experiences. However, we do not yet fully understand what causes some people to have anxiety disorders.
Several drugs can cause or worsen anxiety, whether in intoxication, withdrawal or from chronic use. These include alcohol, tobacco, cannabis, sedatives (including prescription benzodiazepines), opioids (including prescription pain killers and illicit drugs like heroin), stimulants (such as caffeine, cocaine and amphetamines), hallucinogens, and inhalants.[86] While many often report self-medicating anxiety with these substances, improvements in anxiety from drugs are usually short-lived (with worsening of anxiety in the long term, sometimes with acute anxiety as soon as the drug effects wear off) and tend to be exaggerated. Acute exposure to toxic levels of benzene may cause euphoria, anxiety, and irritability lasting up to 2 weeks after the exposure.[87]
Many studies in the past used a candidate gene approach to test whether single genes were associated with anxiety. These investigations were based on hypotheses about how certain known genes influence neurotransmitters (such as serotonin and norepinephrine) and hormones (such as cortisol) that are implicated in anxiety. None of these findings are well replicated.[59][60][61], with the possible exception of TMEM132D, COMT and MAO-A.[63] The epigenetic signature of BDNF, a gene that codes for a protein called brain derived neurotrophic factor that is found in the brain, has also been associated with anxiety and specific patterns of neural activity.[62] and a receptor gene for BDNF called NTRK2 was associated with anxiety in a large genome-wide investigation.[64] The reason that most candidate gene findings have not replicated is that anxiety is a complex trait that is influenced by many genomic variants, each of which has a small effect on its own. Increasingly, studies of anxiety are using a hypothesis-free approach to look for parts of the genome that are implicated in anxiety using big enough samples to find associations with variants that have small effects. The largest explorations of the common genetic architecture of anxiety have been facilitated by the UK Biobank, the ANGST consortium and the CRC Fear, Anxiety and Anxiety Disorders.[64][65][66]
Obsessive-compulsive and related disorders are characterized by obsessive, intrusive thoughts (e.g. constantly worrying about staying clean, or about one's body size) that trigger related, compulsive behaviors (e.g. repeated hand-washing, or excessive exercise). These behaviors are performed to alleviate the anxiety associated with the obsessive thoughts. These types of disorders can restrict participation in everyday life and/or generate significant distress, for instance, by making it difficult to leave the house without many repetitions of a compulsive behavior (e.g. checking that the doors are locked). Periodically experiencing worry or having a few "idiosyncratic" habits does not constitute an obsessive-compulsive or related disorder. Instead, these disorders are characterized by unusually high levels of worry and related compulsive behaviors, in comparison with a typical range of individuals.
There is a long list of signs and symptoms of an anxiety attack. But because each body is somewhat chemically unique, anxiety attacks can affect each person differently. Consequently, anxiety attack symptoms can vary from person to person in type or kind, number, intensity, duration, and frequency. If your symptoms don’t exactly match this list, that doesn’t mean you don’t have anxiety attacks. It simply means that your body is responding to them slightly differently.