Biological Markers in Anxiety Disorders

Abstract

Anxiety disorders are one of the most commonly reported disorders in psychiatry, causing a high medical and socio-economic burden. Recently, there has been a soaring interest in the biological basis of anxiety disorders, which is reflected in an increasing number of articles related to the topic. Due to the ambiguity of the diagnosis and a large number of underdiagnosed patients, researchers are looking for laboratory tests that could facilitate the diagnosis of anxiety disorders in clinical practice and would allow for the earliest possible implementation of appropriate treatment. Such potential biomarkers may also be useable in monitoring the efficacy of pharmacological therapy for anxiety disorders. Therefore this article reviews the literature of potential biomarkers such as components of saliva, peripheral blood, cerebrospinal fluid (CSF), and neuroimaging studies. There are promising publications in the literature that can be useful. The most valuable and promising markers of saliva are cortisol, lysozyme, and α-amylase (sAA). In the blood, in turn, we can distinguish serotonin, brain-derived serum neurotrophic factor (BDNF), cortisol, and microRNA. Structural changes in the amygdala and hippocampus are promising neuroimaging markers, while in CSF, potential markers include oxytocin and 5-Hydroxyindoleacetic acid (5-HIAA). Unfortunately, research in the field of biomarkers is hampered by insufficient knowledge about the etiopathogenesis of anxiety disorders, the significant heterogeneity of anxiety disorders, frequent comorbidities, and low specificity of biomarkers. The development of appropriate biomarker panels and their assessment using new approaches may have the prospective to overcome the above-mentioned obstacles.

Is There Any Association Between Chronic Periodontitis and Anxiety in Adults? A Systematic Review

“…On the other hand, previous evidence indicated a process of HPA axis exhaustion after prolonged periods of stress, this would lead to a reduction in the release of cortisol by the adrenal glands ( 78 , 79 ), as was the case identified in a study in which anxious individuals had reduced levels of cortisol when compared to non-anxious individuals ( 80 ). Therefore, more studies must be performed to establish cortisol as an anxiety biomarker ( 81 ). Another mechanism resulting from anxiety is the stimulation of the central nervous system with the release of adrenaline and norepinephrine, which also have immunosuppressive action ( 82 ).…”

Effects of Acute Psychological and Physiological Stress on Rock Climbers

“…It is possible that the variations in concentrations between the 8:00 a.m. samples of each day were due to individual error or individual variation in diurnal cortisol slope (DCS). Cortisol concentrations can be easily affected by acute stressors, age, sex, nutrition, sleep, hydration, physical activity, and circadian rhythm [ 4 , 9 , 18 ]. Salivary composition can also be affected by countless factors, including circadian rhythm, age, sex, smoking, diet, and medications [ 4 ].…”

“…Cortisol concentrations can be easily affected by acute stressors, age, sex, nutrition, sleep, hydration, physical activity, and circadian rhythm [ 4 , 9 , 18 ]. Salivary composition can also be affected by countless factors, including circadian rhythm, age, sex, smoking, diet, and medications [ 4 ]. Since external factors of the participants’ day to day were not accounted for, it is possible that variations in these variables altered their DCS.…”

“…This can be done by analyzing video footage and utilizing electromyography (EMG) to determine premotor time and reaction time, as well as changes in muscle activity. Blood samples can also be taken to look at the impact that acute stressors have on biomarkers of oxidative stress, as well as on biomarkers that are suggested to be related to anxiety [ 4 ].…”

“…The HPA axis starts with the secretion of corticotropin-releasing hormone (CRH) from the hypothalamus, followed by the release of adrenocorticotropic hormone (ACTH) from the pituitary gland, and finally the release of glucocorticoids from the adrenal glands. Since cortisol can be used as a biological marker of stress, several studies have measured it either via plasma or salivary samples [ 2 , 4 , 5 ]. The gold standard for salivary cortisol sampling is the passive drool (PD) method, since the effect of flow rate on saliva composition can be discarded [ 6 ].…”