Anxiety is considered a common aspect of life, however anxiety disorders develop when feelings of apprehension and unease persist over an extended period and potentially worsen over time. Anxiety disorders, which are believed to stem from a set of risk factors including genetics, neurochemistry, life experiences and personality, can have a range of symptoms and lead to an impact on personal health as well as social and professional interactions. Furthermore, it is common for those suffering with an anxiety disorder to also have a co-occurring disorder or physical illness, which can compound symptoms and complicate recovery. For example, it is estimated that half of patients diagnosed with depression also suffer from an anxiety disorder.
There are several types of anxiety disorders, including generalized anxiety disorder, social anxiety disorder and panic disorder, which are distinct but share common symptoms. In aggregate, anxiety disorders are considered to be the most common mental illness in the United States, affecting approximately 40 million adults, or 18% of the population. Furthermore, the total annual cost of anxiety disorders in the United States is estimated to be over $42 billion, of which more than 75% can be attributed to morbidity, mortality, lost productivity and other indirect costs.
Generalized anxiety disorder (GAD) is characterized as excessive, prolonged and difficult to control anxiety and stress that can impact normal life activities. GAD symptoms can vary, but may include behavioral traits such as unwarranted or disproportional anxiety, difficulty handling uncertainty and indecisiveness, in addition to physical signs such as fatigue, irritability and trembling. Within the United States, GAD affects almost 7 million adults. GAD is diagnosed when an individual finds it challenging to control anxiety on more days than not for at least a six month period and has three or more symptoms. GAD can emerge gradually and most frequently manifests between childhood and middle age.
Anxiety disorders are generally treated with medication, psychotherapy or both. However, despite availability of a range of treatments, only approximately one third of those suffering an anxiety disorder receive treatment.
First line therapy often involves use of antidepressants including SSRIs, such as paroxetine, sertraline and citalopram. SSRIs work by increasing levels of serotonin in the brain, however, they typically have a slow onset of action, with treatment required for four to six weeks before significant therapeutic benefits are observed, with maximal benefits requiring up to twelve weeks of treatment. SSRIs also have a number of side effects, such as sexual dysfunction, drowsiness and weight gain.
Benzodiazepines are also used to treat anxiety and can offer rapid reduction of symptoms with relief as soon as thirty minutes after administration, however, their long-term use is associated with the development of tolerance, respiratory depression, particularly reduction of living compounds, and drug dependence. Some patients experience sedative side effects resulting in drowsiness or lethargy, decreased mental sharpness, slurring of speech and some decrease in coordination or unsteadiness of gait, less occupational efficiency or productivity and, occasionally, headache.