The relationship between anxiety disorders and mood disorders is complex and unique. For a person, anxiety can lead to avoidance and isolation. Isolation may lead to a lack of opportunities for enjoyable experiences, resulting in low mood. For others, emotions may flow in the opposite direction. Being depressed can sap someone's energy to do the things they normally enjoy, and trying to reintegrate into the world after losing practice can cause tension.

Understanding the relationship between the two emotions (anxiety and depression) can help you determine how to better recover.

Anxiety and depression are often comorbid

Anxiety disorders and mood disorders, like major depressive disorder and bipolar disorder, exhibit distinct symptoms, but there's a noticeable overlap. Individuals with generalized anxiety disorder may encounter symptoms of depression, while those with major depressive disorder may also grapple with heightened anxiety. For instance, if you're dealing with depression and start to feel anxious about it, such as worrying that your depression won't improve, this added anxiety can exacerbate your overall condition.

Furthermore, scientists note that these conditions often occur together, which they refer to as comorbidities. As the authors of a recent study[1] wrote :“Up to 90 percent of people with anxiety disorders meet criteria for a co-occurring mood disorder, and up to 70 percent of people with mood disorders meet criteria for an anxiety disorder during their lifetime.”

A meta-analysis study,[2] involving 88,336 individuals, investigated the prospective link between anxiety and depression at both symptom and disorder levels. The findings indicated that various anxiety symptoms were predictive of future depressive symptoms, and conversely, different depressive symptoms were predictive of later anxiety symptoms.

Maggie Holland, a licensed mental health clinician based in Washington, D.C., pointed out that anxiety is frequently associated with concerns about predicting the future, whereas depression is often linked to dwelling on the past. Holland also highlighted the intriguing fact that both anxiety and depression can be rooted in the same part of our brain, the amygdala. She emphasized that the efforts to regulate your nervous system, foster a sense of safety, and manage your emotions are equally applicable to both anxiety and depression.

Anxiety and depression share the same biology

Anxiety and depression share a common biological basis. Although anxiety and depression are experienced differently. However, these two issues can be viewed as two sides of the same coin. Anxiety and depression can occur sequentially (one reaction to the other) or simultaneously. When both anxiety and mood problems reach clinical diagnostic thresholds, specific diagnoses are considered comorbid.

Neurotransmitters function similarly

A persistent state of anxiety or low mood involves changes in neurotransmitter function. For example, low serotonin levels can be attributed to both disorders. In addition to low serotonin levels, other brain chemicals such as dopamine and adrenaline are thought to play a role in both conditions. These neurotransmitter levels are very important when looking for effective forms of medication, which is why anxiety and depression are often treated with the same medications.

Neurological similarities

There may be neurological similarities between anxiety and depression. A recent study published in JAMA Psychiatry[a] aimed to identify these common neurological signatures. The scientists studied 367 MRI (fMRI) scans, including data from 4,507 people with mental health disorders and 4,755 healthy control participants. In total, they analyzed more than 9,000 brain scans. Researchers have found that certain features of brain activity are consistent across mood disorders, post-traumatic stress disorder and anxiety disorders. The researchers detected statistically low activity areas in the inferior prefrontal cortex/insula, inferior parietal lobule, and putamen. These areas are involved in emotional and cognitive control. Also in people with mood disorders, post-traumatic stress disorder and anxiety disorders, the anterior cingulate cortex, left amygdala and thalamus were more active. These areas are important for processing emotional thoughts and feelings.

In an article by McTeague and colleagues [3], the authors employ meta-analytic techniques to explore the neural changes associated with abnormal emotion processing that are common to various psychiatric disorders. The results indicate that alterations in the salience, reward, and lateral orbital nonrewarded networks are consistent across disorders, such as anxiety and depressive disorders. These findings contribute to the growing body of research supporting the idea that there are shared underlying factors across all types of psychopathology, encompassing dimensions of internalizing, externalizing, and thought disorders [4]。

In addition, genes and similar brain structures or processes may contribute to the development of both disorders.

Various types of stress and trauma can also lead to depression and anxiety disorders.

Drugs used to treat anxiety and depression are similar

The most efficient drug treatments for anxiety and depression share similarities but exert distinct effects on brain neurotransmitters. For instance, commonly prescribed medications for managing both conditions include selective serotonin reuptake inhibitors (SSRIs) and serotonin-norepinephrine reuptake inhibitors (SNRIs).

Selective serotonin reuptake inhibitors (SSRIs), more commonly recognized as antidepressants, work by slowing down the reabsorption of serotonin in brain nerve cells, which helps regulate mood and alleviate anxiety. Because of this mechanism, SSRIs are typically the initial choice for treating depression or generalized anxiety disorder. It's worth noting that SSRIs may take a few weeks to show their full effects, but research has demonstrated that they effectively reduce symptoms in the majority of individuals who use them.

Another class of SSRI drugs employed as anti-anxiety medications is benzodiazepines, often referred to as "benzos." These drugs are utilized for short-term relief of anxiety symptoms due to their rapid action, but they are not recommended for long-term use due to their quick onset and the potential for physical dependence.

In addition, serotonin-norepinephrine reuptake inhibitors (SNRIs) function by impeding the reabsorption of serotonin and norepinephrine in the brain. These medications are prescribed to manage both anxiety and depression.

Natural Treatments for Anxiety and Depression

We know that anxiety disorders and depression are often comorbid and that they share the same biological pathogenesis. Therefore the same natural remedies are often used in treating anxiety and depression. For example: exercise, diet, supplementing nutrients, etc.

REF:

[1]Janiri D, Moser DA, Doucet G E, et al. Shared Neural Phenotypes for Mood and Anxiety Disorders: A Meta-analysis of 226 Task-Related Functional Imaging Studies. JAMA Psychiatry. 2020;77(2):172–179. doi:10.1001/jamapsychiatry.2019.3351

[2]Jacobson, Nicholas & Newman, Michelle. (2017). Anxiety and Depression as Bidirectional Risk Factors for One Another: A Meta-Analysis of Longitudinal Studies. Psychological Bulletin. 143. 1155-1200. 10.1037/bul0000111.

[3]McTeague LM, Rosenberg BM, Lopez JW, et al.: Identification of common neural circuit disruptions in emotional processing across psychiatric disorders. Am J Psychiatry 2020; 177:411–421 Link, Google Scholar

[4]Caspi A, Moffitt TE: All for one and one for all: mental disorders in one dimension. Am J Psychiatry 2018; 175:831–844 Link, Google Scholar