This document provides an overview of anxiety, depression, and stress. It defines each condition and lists their common types and symptoms. It also describes the mechanisms of each condition in the brain and body. For anxiety, it explains how the brain floods with stress hormones in response to perceived threats. For depression, it discusses how nerve cell connections and growth can impact mood regulation. For stress, it outlines how the hypothalamus-pituitary-adrenal axis and sympathetic nervous system activate the fight or flight response through hormone releases.

1. Table of Contents
Introduction
Definitions
Types ofanxiety
Types ofdepression
Types ofstress
Mechanismof anxiety
Mechanismof depression
Mechanismof stress
References
 Introduction:
Mental diseases are illnesses that impact your thoughts, feelings, emotions, and actions. They
could be short-term or long-term (chronic). They can have an impact on your capacity to
communicate with others and function on a daily basis. Dysphoria, hopelessness, devaluation of
life, self-deprecation, lack of interest or involvement, anhedonia, and inertia are all symptoms
assessed on the depression subscale. Subscales for anxiety examines autonomic arousal,
skeletal musculature, and autonomic arousal symptoms effects, anxiety in certain situations,
and anxious people's subjective experience affect. The stress subscale measures symptoms
such as trouble relaxing, anxious alertness, being easily upset or agitated, being irritable or
overly reactive, and being impatient. The scales together cover a wide spectrum of symptoms
associated with psychological discomfort.
 Depression:
Depression is characterized by a persistent low mood and a loss of interest in activities that you
used to like. You may also experience sleep and appetite issues, as well as feelings of guilt, de-
motivation, and a general desire to withdraw from others.

2.  Stress:
Overwhelmedness is a common symptom of stress. This sensation could be caused by an
overstretched coping capacity or a prolonged period of stress. While some stress might assist us
in performing daily tasks, too much stress can leave us feeling "distressed" and weary.
 Anxiety:
Anxiety is defined as a fear or dread of something bad happening. Anxiety can be generic or
specific to a location, a social situation, or a particular item (phobia).
Anxiety, Stress and Depression
Types of Anxiety:
 Generalized anxiety disorder:
GAD is an anxiety condition characterised by persistent anxiety, increased worry, and tension,
even when there is little or no cause for it. GAD is an anxiety condition characterised by
persistent anxiety, increased worry, and tension, even when there is little or no cause for it.
 Obsessive-Compulsive Disorder:
OCD is an anxiety condition marked by recurring, unwanted thoughts (obsessions) and/or
repetitive activities (compulsions). Hand washing, counting, checking, and cleaning are all
common repetitive behaviours used to try to prevent or eliminate obsessive thinking. However,
performing these so-called "rituals" only provides momentary respite, and failing to do so
increases anxiety significantly.

3.  Panic disorder:
Panic disorder is an anxiety illness marked by sudden and recurring episodes of great terror, as
well as physical symptoms such as chest discomfort, heart palpitations, and shortness of
breath, dizziness, or gastrointestinal problems.
 Post-Traumatic Stress Disorder:
PTSD is an anxiety condition that can develop after witnessing a distressing event or encounter
in which substantial physical injury happened or was threatened. Violent personal assaults,
natural or man-made disasters, accidents, or military combat are all examples of traumatic
events that can lead to PTSD.
 Social phobia or social anxiety disorder:
Fear disorder characterised by extreme anxiety and excessive self-consciousness in everyday
social interactions is known as social phobia, or social anxiety disorder. Social phobia can be
limited to a single type of situation - such as a fear of speaking in official or informal contexts, or
of eating or drinking in front of others - or it can be so broad that a person has symptoms
practically whenever they are with other people in its most extreme form.
Types of Depression:
 Major depressive disorder:
When individuals talk about clinical depression, they're usually talking about major depressive
disorder (MDD). Major depressive disorder (MDD) is a mood illness with several distinct
characteristics. Depressed mood, lack of interest in activities normally enjoyed, changes in
weight, changes in sleep, fatigue, feelings of worthlessness and guilt, difficulty concentrating,
thoughts of death and suicide.
 Persistent Depressive Disorder:
Dysthymia, also known as persistent depressive disorder, is a type of chronic depression that
lasts for at least two years and is present on more days than not. It can range from minor to
severe. People may feel better for a short time but just for two months or less. While the
symptoms are not as severe as those associated with major depression, they are widespread
and long-lasting. Feelings of sadness, loss of interest and pleasure, anger and
irritability, feelings of guilt, low self-esteem, difficulty falling or staying asleep,
sleeping too much.

4.  Bipolar Disorder:
Mania is a symptom of bipolar disorder, which is marked by moments of unusually heightened
mood. These episodes can be mild (hypomania) or severe (mania), requiring hospitalization or
affecting a person's sense of reality. The great majority of people who have bipolar disorder
also suffer substantial depressive episodes. Symptoms include; fatigue, insomnia, and lethargy,
unexplained aches, pains, and psychomotor agitation, hopelessness and loss of self-esteem,
irritability and anxiety, indecision and disorganization.
 Postpartum Depression:
Pregnancy can cause major hormonal changes, which can have a negative impact on a woman's
mood. Depression can strike during pregnancy or shortly after a child is born. Postpartum
depression (PPD) is more than just the "baby blues," as it is currently categorized as depression
with peripartum start. After giving birth, mood swings, anxiety, irritability, and other symptoms
are common and can persist up to two weeks. The symptoms of PPD are more severe and stay
longer. Symptoms include; low mood, feelings of sadness severe mood swings, social
withdrawal, trouble bonding with your baby, appetite changes, feeling helpless and hopeless.
 PremenstrualDysphoric Disorder:
Irritability, exhaustion, anxiety, moodiness, bloating, increased hunger, food cravings, pains,
and breast tenderness are just a few of the most typical symptoms of premenstrual syndrome
(PMS). Symptoms may include; extreme fatigue, feeling sad, hopeless, or self-critical, severe
feelings of stress or anxiety, mood swings, often with bouts of crying, irritability.
 Seasonal Affective Disorder:
You may have seasonal affective disorder (SAD), also known as major depressive disorder with
seasonal pattern, if you have depression, drowsiness, and weight gain throughout the winter
months but feel fine in the spring. SAD is thought to be caused by a disruption in the body's
natural circadian cycle. This rhythm is influenced by light entering the eyes, and any seasonal
difference in the night/day pattern might create a disruption, leading to depression. Because
SAD is frequently untreated and undocumented, determining prevalence statistics can be
difficult.
 Atypical Depression:
Do you show indicators of depression (such as overeating, sleeping too much, or being overly
sensitive to rejection) but then perk up when confronted with a happy event? You could be
diagnosed with atypical depression (also known as depressive disorder with atypical features)

5. based on these symptoms, which is a type of depression that doesn't express itself in the
"normal" way. Atypical depression is defined by a group of symptoms that are unique to it.
Atypical epression is more frequent than its name suggests. People with atypical depression
may respond better to a type of antidepressant than those with other types of depression.
Symptoms may include; excessive eating or weight gain, excessive sleep, fatigue, weakness, and
feeling "weighed down", intense sensitivity to rejection, strongly reactive moods.
Types of stress:
 Acute stress:
Acute stress is the form of stress that knocks you off your feet for a short period of time.
This is the type of stress that comes on suddenly and frequently unexpectedly, lasts a short
time, but requires a response and shakes you up a little, such as a disagreement with a
loved one or an exam for which you are unprepared.
 Chronic stress:
Chronic stress is a form of anxiety that occurs on a regular basis. If not properly managed,
this form of stress can leave you feeling tired and even lead to burnout. This is because the
body might stay triggered indefinitely if the stress response is persistently aroused and the
body is not brought back to a relaxed state before the next wave of stress arrives.
Managing this sort of stress frequently necessitates a combination of short-term stress
relievers (such as those for acute stress) and long-term stress reduction practises that
reduce overall stress. (There are also many emotion-focused and solution-focused coping
approaches to consider.)
 Emotional stress:
Emotional stress can be far more painful than other types of stress. For example, stress
from a tense relationship causes a bigger bodily reaction and a greater sense of anxiety than
stress from a hectic job schedule.
As a result, being able to effectively regulate emotional stress is critical. Different ways can
work in different scenarios when it comes to helping you process, diffuse, and build
resilience in the face of emotional stress.
 Battling burnout:

6. Burnout is caused by long-term chronic stress from events that make people feel powerless
in their life. Certain job conditions, including not only a high level of demands, but also
imprecise expectations, a lack of appreciation for accomplishments, and a significant danger
of severe repercussions when mistakes are made, can increase the risk of burnout. Once
you've reached a point of burnout, it's tough to stay motivated to work and do what you've
set out to do, and you may feel chronically overwhelmed. The following tactics, in addition
to those that work effectively for chronic stress and emotional stress, can help you recover
from a state of stress.
Mechanism of stress:
The first step in stress response is the perception of the threat (stressor). Whenever there is
some stressor - real or imagined, it acts at the level of brain. In the brain, it is the hypothalamus
which perceives the stressor. When the hypothalamus encounters a threat it performs some
specific functions: activates autonomic nervous system (ANS).Stimulates Hypothalamic
Pituitary Adrenal (HPA) axis by releasing Corticotrophin Releasing Hormone (CRH) and . Secrets
arginine vasopressin (Antidiuretic Hormone ADH). Autonomic nervous system consists of
sympathetic (arousal) and parasympathetic (relaxed) nervous system. The ANS regulates
visceral activities like circulation, digestion, respiration, temperature regulation and some vital
organs. The sympathetic system accounts for the flight-or-flight response. In response to a
stressor catecholamines: epinephrine (adrenaline) and norepinephrine (nor adrenaline) are
released at various neural synapses. The release of these catecholamines causes several
changes like increase in the heart rate and force of myocardial contraction vasodilatation of
arteries throughout working muscles and vasoconstriction of arteries to nonworking muscles;
dilation of pupil and bronchi and reduction of digestive activities in the body. All these changes
are required to prepare the body for fight-or-flight response. The effects of these hormones -
epinephrine and nor epinephrine last for few seconds. The functions of parasympathetic
nervous system are opposite to that of sympathetic nervous system and help in energy
conservation and relaxation.
CRH acts at the anterior pituitary gland an endocrine gland located in the brain. Pituitary gland
is also called ‘master gland’, as it controls the secretion of other endocrine glands in the body.
On stimulation by CRH, anterior pituitary secretes Adrenocorticotropin Hormone (ACTH).
Arginine vasopressin modulates the effect of CRH on ACTH secretion.
ACTH released from anterior pituitary gland in response to CRH stimulates adrenal glands
located on the kidneys. There are two parts of adrenal - the outer part called cortex and the
inner part known as medulla.
ACTH stimulates adrenal cortex to release corticoids (glucocorticoids and mineralocorticoids).
The major function of glucocorticoids is to release energy, which is required to cope with the ill
effects of stressor. The energy is released by conversion of glycogen into glucose
(glycogenolysis) and also by breakdown of fats into fatty acids and glycerol (lipolysis). In

7. addition to this corticoids have several other functions such as: increased urea production,
appetite suppression, suppression of immune system, exacerbation of gastric irritation,
associated feeling of depression and loss of control. These are the symptoms generally seen in a
person under stress. Mineralocorticoid (aldosterone) promotes Na+ retention and elimination
of K+. It increases blood pressure by increasing blood volume. The medulla part deof the
adrenal gland secretes epinephrine and norepinephrine. The functions of these hormones are
the same as that of those secreted from nerve endings of sympathetic nervous system. These
hormones secreted by adrenal medulla, reinforce the functions of sympathetic nervous system.
The release of these hormones from adrenal medulla acts as a backup system to ensure the
most efficient means of physical survival. The effects brought out by epinephrine and
norepinephrine from the sympathetic nervous system may be termed as immediate effects and
the effects brought out by those of adrenal medulla are intermediate effects. The basic function
of vasopressin or ADH synthesised by hypothalamus and released by posterior pituitary is to
regulate fluid loss through urinary tract. This is achieved by reabsorption of water. In addition,
ADH also has a prominent role on regulation of blood pressure during stress when the
homeostasis of the body is disturbed in addition to release of energy second major change
occurring during stress is distribution of energy to a particular organ that needs it most. This is
achieved by increasing blood pressure. This occurs either through enhanced cardiac output or
through constriction of blood vessel.
In addition to HPA axis some other hormones such as Growth Hormone (GH) and thyroid
hormones also play significant role in stress. Growth hormone is a peptide hormone, released
from anterior pituitary gland. GH is a stress hormone that raises the concentration of glucose
and free fatty acids. It has been observed that, in human beings psychological stimuli increase
the concentration of thyroid hormones. Thyroid releases thyroxin and triiodothyronine. These
hormones also have some significant function in stress. The main function of thyroid hormones
is to increase overall metabolic rate or Basal Metabolic Rate (BMR). Thyroxin also increases
heart rate and also the sensitivity of some tissues to catecholamines.
Though, serotonin and melatonin are not considered as stress hormones yet they are
associated with mood. A decrease in the levels of these hormones is thought to be related to
depression.
Mechanism of depression:
One of the most difficult aspects of understanding depression is pinpointing its root causes, as
they vary from person to person. Sometimes, the reason is clear, such as witnessing or living
through a traumatic event. Other times, the reason for depression is subtle and hidden under
layers of suppressed memories. There are even times when we’re depressed for no clear
reason. To help us understand why depression can manifest itself in so many different ways,
researchers study the brain. Since our brains control, manage and balance our emotions, they
are the key to understanding how and why we develop depression in the first place.

8. A Harvard Medical School special report, “Understanding Depression” explains the condition
like this: “Certain areas of the brain help regulate mood. Researchers believe that—more
important than levels of specific brain chemicals—nerve cell connections, nerve cell growth,
and the functioning of nerve circuits have a major impact on depression.”
Many of us blame our brain “chemistry” for depression or anxiety. But research like the report
above indicates that the brain’s role in depression is much more complex than simply regulating
emotions. Instead, the difference between a person who struggles with depression and a
person who does not may have more to do with how the different parts of our brain work
together.
In some cases, the connections in our brains aren’t as strong as they should be, while
sometimes the cells in our brain may have grown differently. In other cases, one or more of our
neurons may send incorrect information through different areas of our brain. When our brain
acts in such ways, we may experience the kind of biochemical trauma that can cause
depression, even if we haven’t lived through any kind of emotional, physical, or spiritual trauma
in our lives.
When different parts of our brains aren’t communicating, chemical messengers called
neurotransmitters are often involved. This is because neurotransmitters help make sure the
different parts of our brains work well together.
Mechanism of anxiety:
1. Anxiety Floods Your Brain with Stress Hormones
 When you feel anxious, your body goes on alert, prompting your brain to prepare itself for
flight or fight mode. In an attempt to help you fight off whatever has made you anxious, your
brain floods your central nervous system with adrenaline and cortisol. These hormones tell your
body that something scary is about to happen. Their role is to help you cope with danger. In
order to do that, they sharpen your senses and make your reflexes faster. In a non-anxious
brain, when the danger is gone, the sympathetic part of your nervous systemtakes over and
calms you down. But when you suffer from anxiety, you may not be able to reach that sense of
calm. Instead, the rush of stress hormones causes your brain to release even more stress
hormones until you’re simply overwhelmed.
When excess amounts of stress hormones flood the brain over and over again, your baseline
level of anxiety may increase. You might go from having mild anxiety, which most of us
experience on a day-to-day basis, to moderate anxiety. Moderate anxiety is slightly more
severe and overwhelming and makes you feel nervous and agitated on a regular basis. If your
brain continues to be overly sensitive to anxiety, your baseline anxiety level might become so
severe that you’re unable to continue thinking rationally. Panic attacks are another sign
of severe anxiety. If you have moderate or severe levels of anxiety, brain maps
called Quantitative Electroencephalography (qEEG) may show a large amount of high beta brain
waves on the right lobe.
2. Anxiety Makes Your Brain Hyperactive to Threats:

9.  Anxiety can also make your brain hyperactive to threats. When you deal with anxiety on a
consistent basis, your amygdala grows larger. The amygdala is a tiny almond-shaped structure
located in the limbic system, the part of your brain that deals with emotions and moods. The
amygdala is like your brain’s watchman, staying on the lookout for any danger or threats. When
the amygdala notices potential danger, it sends signals to the hypothalamus, which triggers a
fight or flight response. In the anxious brain, the amygdala is large and hypersensitive. Because
of this, the amygdala sends a lot of false alarms. You can think of a hypersensitive amygdala as
a watchman who cries wolf too often. An overactive amygdala sends false alarms so often that
your brain senses threats even in non-threatening situations. That’s why people with anxiety
disorders tend to feel threatened more often than someone without such a disorder.
3. Anxiety Can Make It Hard for Your Brain to Reason Rationally
 Anxiety weakens the connections between the amygdala and the prefrontal cortex (PFC). When
the amygdala alerts the brain to danger, the prefrontal cortex should kick in and help you come
up with a rational, logical response. The PFC ensures that you’re capable of processing
information analytically and can make informed decisions, as well as helping you solve
problems. You can think of the PFC as your brain’s wise counselor. In non-anxious brains, the
prefrontal cortex responds rationally when the amygdala sends out alerts. This process doesn’t
work the same in anxious brains. Instead, when the amygdala alerts the PFC to danger, the
connection is weak. Thus the rational, problem-solving part of the brain isn’t heard, which can
lead to irrational thoughts and erratic behavior.
4. Anxiety Can Train Your Brain to Hold Onto Negative Memories
 When you’re anxious, your body is under a lot of stress. Stress shrinks the hippocampus, the
part of the brain that processes long-term and contextual memory. When the hippocampus
shrinks, it may become more difficult for your brain to hold onto memories. But here’s the
tricky part: anxiety tricks the hippocampus into thinking that memories related to anxiety are
safe to store and remember. So, the few memories you do hold onto will be those related to
anxiety. In other words, anxiety wires your brain to remember failure, threat, and danger.
Happier memories, like those of success, achievement, and safety, are buried deep in your
brain’s basement.
 References:
https://pronghornpsych.com/how-does-anxiety-affect-the-brain/.
https://pronghornpsych.com/neurotransmitters-and-depression/.
https://www.heraldopenaccess.us/openaccess/physiology-of-stress-and-its-management.
https://www.verywellmind.com/types-of-stress-and-stress-relief-techniques-3144482.

10. https://www.verywellmind.com/common-types-of-depression-1067313.
https://www.hhs.gov/answers/mental-health-and-substance-abuse/what-are-
the-five-major-types-of-anxiety-disorders/index.html.
https://psychologyonparade.com.au/what-is-the-difference-between-depression-stress-and-
anxiety/.
https://www.researchgate.net/profile/Muhamad-Saiful-Bahri-
Yusoff/publication/243458848_Psychometric_Properties_of_the_Depression_Anxiety_Stress_S
cale_in_a_Sample_of_Medical_Degree_Applicants/links/0046351d119cdc9a85000000/Psycho
metric-Properties-of-the-Depression-Anxiety-Stress-Scale-in-a-Sample-of-Medical-Degree-
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