Anxiety is an essential reaction of the central nervous system (CNS) to potential or uncertain threats. It is an unpleasant experience which encourages us to take action to prevent harm. This concept is essential to understanding the causes of anxiety disorders - the thoughts and behavioral symptoms can be seen as a form of self-protection and are hard to resist.
Anxiety disorders are common and can be greatly debilitating. The YLD (years lived with disability) burden of anxiety disorders carries the same weight as the combined burdens of ischemic heart disease and asthma, in the UK.3 There is, however, a stigma attached to anxiety disorders as people perceive them as a sign of weakness or a lack of ability to handle everyday stress.
Anxiety disorders can be understood as a series of positive feedback loops, as illustrated in Figure 1. Broadly speaking, the brain can process anxiety in a variety of ways, and under certain conditions, the thoughts and behaviors associated with anxiety can intensify and perpetuate the condition. This can lead to unhealthy coping strategies and can eventually spiral into an illness. The severity of the spiral depends on the individual's inherent anxiety response and the amount of stress involved.
“Trait anxiety” is the individual's tendency to experience anxiety when exposed to stressors. It is a product of a variety of genetic and environmental factors, such as a person's prior experiences with potential danger and the relationships formed in early life. High trait anxiety provides a greater survival advantage as it encourages avoidance of potential danger. This is true in both historical scenarios and modern western society.5
The relationships formed in early life also have long-lasting impacts on mental development and capacity. Through regular experiences of care and comfort, an infant is gradually able to internalize their own capacity to manage feelings and cope with anxiety independently.
Parental care which is "good enough" is necessary for healthy development. If care is inconsistent, dismissive or frightening, high trait anxiety and other problems can emerge. "State anxiety" is simply the feeling of being anxious. It is identified as a disorder when it becomes severe and persistent enough to cause significant distress and functional impairment.
A combination of high trait anxiety and psychosocial stressors can overwhelm the normal homeostasis of anxiety and cause excessive and persistent anxiety, where normally harmless situations seem threatening. This is thought to be driven by a few processes, which include avoidance, attentional and cognitive bias, anxious rumination, and low self-worth.
Avoidance is the reason anxiety exists, but it minimises opportunities to unlearn fear of a given stimulus. This perpetuates existing anxiety associated with specific situations or stimuli. This was useful in evolutionary terms, as it helps prepare for danger, but when the stressors causing state anxiety are ubiquitous, this heightened anxiety increases the range of things that are felt anxious about.
State anxiety makes us automatically pay attention to threats and interpret ambiguous information as threatening. This helps anticipate danger, but it can also heighten anxiety in everyday circumstances.
Rumination is continuously thinking about the same thing, and worrying is another function of state anxiety which is useful in evolutionary terms. It is an automatic attempt at problem-solving, which serves to maintain vigilance for potential danger. However, it also increases state anxiety.
Anxiety and depression are very commonly comorbid, and it is often meaningless to separate the two. They can be thought of as a network of feedback loops which generate both anxiety and depressive symptoms.
Negative beliefs about oneself and associated low mood are components of depression that can both increase anxiety and be increased by anxiety. For example, feeling incompetent leads to more anxiety about tasks to complete, while recurrently avoiding situations due to anxiety can lead to feelings of failure.
Sleep is essential for a large variety of bodily functions related to cognition, emotional processing, and memory, among many other things. Therefore, it is no surprise that poor sleep can contribute to many issues, including anxiety disorders. This in turn can create more issues with poor sleep.
Anxiety has a base of neurophysiological changes that include reduced functional connectivity between the prefrontal cortex and the limbic system and variations in serotonin transporter levels, resulting in decreased serotonin signaling. These are the foundation of a "Monoamine Hypothesis" of anxiety and depression, seen in common selective serotonin reuptake inhibitors.
Anxiety is an emotion characterized by feelings of tension, worry, and fear. It is related to the body's fight-or-flight response which triggers physiological changes such as increased heart rate and breathing. Anxiety can be caused by a variety of factors, including genetics, environment, or physical health. Anxiety disorders involve more than temporary worry or fear and can result in disturbances in a person's life.
The Dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) Axis is a term used to describe the self-regulating neuronal and hormonal interaction between the hypothalamus, the pituitary gland and the adrenal glands. This is a central component of the physiological response to stress. It is debated whether these changes are a cause or a result of the psychological processes associated with anxiety.
Changes on functional Magnetic Resonance Imaging (fMRI) of the brains of patients with anxiety or depression have been demonstrated following pharmacological or psychological treatment.
Anxiety disorders can be broadly similar in terms of symptoms, however, they can be distinguished by their diagnostic criteria. Common symptoms of anxiety can include subjective feelings of nervousness, difficulty maintaining concentration, muscular tension or motor restlessness, sympathetic autonomic over-activity, irritability and sleep disturbance. Anxiety disorders are assessed based on criteria which include symptoms lasting for several months, significant impairment in various areas, and exclusion of other health conditions.
Generalized Anxiety Disorder (GAD) is marked by persistent “free-floating” anxiety (not restricted to particular circumstances) or excessive worry focused on multiple everyday events. It has a lifetime prevalence of 5-12%, with females affected more than males.
Phobic Anxiety Disorders are characterized by abnormal state anxiety evoked only or predominately by a specific external situation or object, plus the avoidance of that situation. Types of phobic anxiety disorders include agoraphobia, social phobia, and specific phobias. Common features include anticipatory anxiety, muscular tension or motor restlessness, somatic symptoms, and sympathetic autonomic over-activity.
Phobic anxiety disorder has a lifetime prevalence of up to 12%, with males and females affected equally.
Panic disorder involves recurrent unpredictable episodes of severe acute anxiety which are not restricted to particular stimuli or situations. These episodes usually involve a crescendo of anxiety and somatic symptoms, as well as a secondary fear of dying or losing control. The lifetime prevalence of Panic Disorder is 4%.
When treating anxiety disorders, psychological therapies aim to address the problem, while medications reduce the intensity of state anxiety in order to facilitate psychological engagement. Often, both approaches are necessary. Treatment is effective, but can take time and a lot of effort, as the patient needs to go against their natural self-protective impulses.
Depending on severity, the stepwise treatment algorithm is as follows:
Benzodiazepines (e.g. diazepam) should be avoided for chronic anxiety. These drugs can have powerful negative reinforcement effects, causing rapid tolerance and addiction. If used, it should be only in cases of transient causes of anxiety or in crisis, with a maximum prescription length of two weeks.
PTSD can develop after exposure to a traumatic event or series of events. It is thought to be caused by impaired memory consolidation, leading to a chronic hyperarousal of fear circuits. Common features of PTSD include (using the mnemonic HARD): Hyperarousal, Avoidance, Re-experiencing, and Distress.
Management of PTSD includes trauma-focused CBT, Eye-Movement Desensitization and Reprocessing (EMDR) therapy, SSRI or venlafaxine, and additional psychoeducation, sleep hygiene, and relaxation methods.
Lifetime prevalence is 2-6%.
C-PTSD may be present after exposure to a series of extremely traumatic events, particularly when these are prolonged or repetitive with difficulty escaping them. C-PTSD is believed to be a result of adapting to prolonged or repetitive trauma, leading to significant modifications of an individual's automatic threat response.
Complex Post-Traumatic Stress Disorder (C-PTSD) is a condition characterized by traumatic experiences, leaving the brain particularly vulnerable. It has many similarities to Emotionally Unstable Personality Disorder (EUPD) and is often viewed as a less stigmatizing explanation for some cases of EUPD.
The diagnostic requirements for C-PTSD include:
Treatment for C-PTSD is similar to that of PTSD and may require long-term psychological therapy.
A group of disorders characterized by repetitive thoughts and behaviours also exists, with specific examples including:
The repetitive thoughts are generally intrusive and distressing (observed in OCD, BDD, and Hypochondriasis), while the repetitive behaviours act as a means of reducing distress, but become difficult to control (i.e. observed in OCD, Trichotillomania/Dermatillomania, and also Hoarding Disorder, which is linked to distress associated with discarding possessions). Anxiety is a predominant feature of these disorders and can lead to repetitive intrusive thoughts and compulsive behaviour in an effort to reduce it.
Treatment for these conditions is similar to the treatment for other anxiety disorders and usually involves a combination of SSRI and psychological therapy. Specific cognitive-behavioural therapies such as Exposure and Response Prevention Therapy may be used for OCD while other medications, such as Clomipramine or adjunctive antipsychotics, may be indicated if SSRIs are not successful.
Anxiety disorders are common and can affect anyone, however, prevalence of these conditions is particularly high among medical students, with approximately one in three medical students experiencing an anxiety disorder globally.
It is normal and adaptive for medical professionals to experience a degree of anxiety; helping to increase their vigilance and motivation with regards to delivering safe care. However, if the anxiety becomes intense and persistent, it can develop into a disorder.
As such, it is important to remember that there is a gradual continuum between everyday stress and anxiety disorders, and interventions are available to prevent the anxiety from advancing. Good sleep hygiene, self-guided anxiety management strategies, and speaking to a GP or someone in a position of pastoral responsibility are highly effective, regardless of where a person may be on the spectrum of anxiety.
Finally, it is essential to strike a balance between two different narratives regarding anxiety: (1) that it is something that can be managed independently, and (2) that it is an illness requiring professional input.
We are constantly bombarded with conflicting messages that can easily worsen our existing anxiety and cause us to question our self-worth. This can lead to feeling guilty for not being resilient enough, or feeling unable to manage our anxiety independently. Having the ability to thoughtfully reflect on this is an important skill for both ourselves and our patients.
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Depression and anxiety affect a large portion of the population, and understanding these conditions is important. There are a variety of resources available for those looking to learn more about depression and anxiety.
