Issues in Interdisciplinarity 2020-21/Evidence in the Development and Diagnosis of Anxiety Disorders

Introduction
Anxiety is a common feeling of everyday life and can affect anyone who is under stress, whether it be before the deadline of an assignment or when practicing for the final of a sports tournament. It is positive and essential, providing that extra boost of adrenaline and motivation enabling success. But simple anxiety can become harmful to someone’s mental health when diagnosed with General Anxiety Disorder (GAD), defined by the Cambridge Dictionary as “a mental illness in which a person is so anxious that their normal life is affected”. Historically, the diagnosis of GAD as a specific illness was very blurry because of the similarities it shares with other conditions such as phobias, OCD (Obsessive-compulsive Disorder) or PTSD (Post-Traumatic Stress Disorder), often being considered a symptom of these disorders rather than a disease itself. The fact that mental health issues remained taboo in many cultures until very recently also did not help for developing our knowledge and financing research on these disorders. Furthermore, the more scientific disciplines, such as neurobiology, tend to disagree with anthropology, the first focusing on genetics and biochemical abnormalities while the second puts an emphasis on the cultural environment. This contrast creates issues of evidence between disciplines in the understanding of GAD in its development and diagnosis.

Anthropological Approach
The anthropological approach to anxiety focuses on the impact culture has on the causes and symptoms of the disorder. As argued by American anthropologist Franz Boas, historical and environmental backgrounds are essential for interpreting the psychological state of people in different cultures. Therefore, anthropology emphasizes cross-cultural differences in the expressions of anxiety and their underlying factors.

Finding Cross-Cultural Differences
Statistical data is used intensively in identifying the cross-cultural differences in the prevalence and major symptoms of these conditions among different ethnic groups. In a national survey on mental health in the United States, Asian Americans were reported to have the lowest rate of anxiety disorders (Table 1). Furthermore, expressions and symptoms of anxiety also vary and can be culturally-specific. Taijin kyofusho (TKS) is a social anxiety disorder more commonly found in Japan and Korea than in other regions and is characterized by the intensified concern of embarrassing others on social occasions.

Contextualising Differences
Contextualization of the differences is usually done by case studies including interviews with patients. Anthropologists take secondary evidence from patients’ self-reflections on their symptoms and past experiences to examine the relations between cultural beliefs and disorders. For instance, the potential link between the traditional belief of harmony and the prevalence of dizziness as a panic attack symptom is suggested by interviews with Chinese patients suffering from panic disorders. Other factors like social norms also contribute to the differences. People from collectivistic countries are reported to feel more embarrassment when rating certain behaviors in an experiment compared to people from individualistic countries, which may result in a high level of social anxiety in certain Asian countries.

Neurobiological Evidence for Anxiety Disorders
Neurobiology explores the anatomy of the nervous system and how this links to behaviour, an essential component of physiology and neuroscience.

GAD and other related disorders can be observed and explained biologically through research with animal models and newly developed techniques such as neuroimaging with humans. It has been determined that genetic predispositions to GAD and other mental disorders exist in certain individuals and that environmental factors also have an influence, possibly increasing risk factors for developing such disorders.

A growing amount of research in biology and psychiatry is currently being conducted in order to identify pathogenetic biomarkers, essentially underlying biological and genetic factors, that are linked to GAD. Neuroimaging techniques, including Magnetic Resonance Imaging (MRI), have been particularly helpful in determining structural and biochemical abnormalities in individuals with GAD. Findings include an increased amount of grey matter in the amygdala, a part of the limbic system involved in the processing of fear, while the hippocampus is typically abnormally low in volume. Such structural differences, among others, are believed to be linked to issues in regulating emotion and certain symptoms of GAD. In addition, different studies have demonstrated the heritability of GAD, one of them getting a result of 49%. While intensive research is being led in order to determine the exact genes responsible for this predisposition, we remain largely in the dark on the topic.

Psychiatry and Evidence in the Diagnosis of Anxiety Disorders
One of the main issues in treating anxiety is successfully diagnosing it. Even if this disorder is very common among children and adults it remains one of the most misdiagnosed among the medical community. Although psychiatry is increasingly making use of neurobiology, particularly in the treatment of GAD through medication, the diagnosis of mental health disorders continues to widely rely on behavioural observations and qualitative evidence. Indeed, diagnoses are made using a range of qualitative tools such as clinical interviews, questionnaires and self-reporting, which may be deemed subjective and unreliable. Psychiatrists are then faced with the difficulty of associating behavioural and emotional symptoms with a specific disorder, using guidelines and diagnostic manuals such as the Diagnostic and Statistical Manual of Mental Disorders (DSM). This is particularly hard in the case of different anxiety disorders and depression which often have very similar manifestations. What may be observed is quite a significant lack of the use of neurobiology in the actual diagnosis of disorders such as GAD. Indeed, although neuroimaging could potentially solve some issues of subjectivity, such techniques are not currently advanced enough to be able to definitively tell different mental health conditions apart.

Conflicts of evidence between disciplines
Anxiety sits on a very fine line between a feeling of discomfort and a medical condition. While trying to make the distinction clearer, disciplines have each focused on different aspects of the disorder. Anthropology studies the impact of culture on individuals and the patient’s perception, while neurobiology finds evidence for anxiety in hereditary genes causing abnormalities in the brain. Indeed, while both disciplines explore aspects of GAD through research, sometimes with some overlap, a lack of collaborative engagement exists between them. This may explain some of the failures in psychiatric studies and diagnoses of GAD, and a more thorough interdisciplinary approach could be a solution. The emerging field of cultural neuroscience, taking both socio-cultural environments and biological factors into account, may thus be of use to psychiatry in the future. Another issue that needs to be tackled is the complete absence of neurobiology in the diagnosis of GAD. More investments in neuroimaging would increase the precision and utility of this technology and would ultimately allow neurobiology to have a more important role in the diagnosis of this condition. Furthermore, psychiatry primarily focuses on the treatment and diagnosis of the patient, although in many cases anxiety results from socio-cultural issues that cannot be solved only through therapy or medication. A more active engagement with anthropology and social sciences (economics or politics) could thus also be beneficial.