What Is Depression?
Depression—also referred to as major depressive disorder or clinical depression—is the most prevalent mental health condition in the U.S. and worldwide. While it’s normal to feel down occasionally, most people recover from these emotional dips quickly. However, for others, persistent feelings of sadness, emptiness, or hopelessness take hold and begin to disrupt daily thoughts, emotions, and behaviors. When these symptoms continue over time, depression can interfere with your personal and professional life and may lead to both emotional and physical health challenges.
Who Is Affected by Depression?
An estimated 17.3 million adults in the United States are impacted by depression—accounting for over 7% of the adult population. Depression is more commonly diagnosed in women, who are twice as likely as men to experience a depressive episode. Alarming trends show that depression is increasing most rapidly among teens and young adults. Approximately 36% of teenage girls and 13% of teenage boys experience clinical depression during adolescence.
What Are the Consequences of Untreated Depression?
Nearly two-thirds of individuals suffering from depression do not receive proper diagnosis or treatment. Without intervention, depression can take a serious toll on all areas of life. It can increase the likelihood of substance abuse, strain personal relationships, hinder job performance, and elevate the risk for physical health problems. Studies show that individuals with depression are more susceptible to heart disease and face a higher mortality rate following a heart attack compared to those without depression. Perhaps most concerning, depression is a contributing factor in roughly two-thirds of all suicides.
Risks Associated with Untreated Depression:

- Substance abuse and addiction
- Strained or failed relationships
- Difficulty maintaining employment or achieving career goals
- Increased risk of heart disease and related complications
- Higher risk of suicidal thoughts and behaviors
7 Types of Depression
Brain imaging studies have revealed seven unique patterns linked to depression. Understanding the specific type is essential, as each form requires a customized treatment approach for effective relief.
Did you know that anxiety and depression co-occur in about 75% of cases? That’s why Pure Anxiety is included among the 7 types of depression. This type is linked to increased activity in the basal ganglia, which causes the brain’s “idle speed” to run high.
Common symptoms of Pure Anxiety include:
-
Persistent nervousness or anxiety
-
Panic attacks
-
Avoidance of people or places due to fear of panic
-
Muscle tension, headaches, tremors
-
Heart palpitations, dizziness, or nausea
-
Tendency to anticipate the worst
-
Multiple fears or phobias (like fear of dying or losing control)
-
Avoidance of conflict
-
Fear of judgment or embarrassment
-
Startling easily or freezing in intense moments
-
Shyness, social withdrawal, frequent blushing
-
Nail-biting or skin-picking habits
Pure Depression is typically associated with overactivity in the brain’s deep limbic system—the emotional center. This type ranges from chronic low mood (dysthymia) to severe depressive episodes that make daily life feel unmanageable.
Common symptoms of Pure Depression include:
Ongoing sadness or negativity
Loss of interest in enjoyable activities
Irritability, restlessness, or frequent crying
Feelings of guilt, hopelessness, or worthlessness
Sleep issues—insomnia or oversleeping
Appetite changes or weight fluctuation
Low energy or slowed movement
Suicidal thoughts or attempts
Difficulty focusing or making decisions
Physical discomforts like headaches or stomach pain
Low self-esteem
Chronic boredom or dissatisfaction
This type presents a combination of symptoms from both Pure Anxiety and Pure Depression. It shows heightened activity in both the basal ganglia and deep limbic system. While one symptom set may dominate at times, signs of both are usually present consistently.
This subtype shows increased activity in the anterior cingulate gyrus, basal ganglia, and limbic system. It’s more common in individuals with a family history of alcoholism. These individuals often fixate on specific thoughts or behaviors and struggle to shift focus.
In addition to symptoms of Pure Anxiety or Depression, common signs include:
Excessive or irrational worrying
Frustration when plans don’t go as expected
Argumentative or oppositional behavior
Repetitive negative thinking
Addictive or compulsive tendencies
Resistance to change
Holding onto resentment
Inflexible thinking
Strong opinions with poor listening skills
Needing tasks done a specific way
Frequent worry complaints from others
Reflexively saying “no” without considering
This variation is connected to irregular activity in the temporal lobes, which control mood, memory, and emotions. Overactivity may also appear in the basal ganglia and limbic regions.
Symptoms (plus Pure Anxiety/Depression signs) may include:
Short temper or irritability
Unprovoked anger or rage
Misinterpreting comments negatively
Spaciness or confusion
Sudden panic or fear
Visual/auditory changes (shadows, muffled sounds)
Déjà vu experiences
Mild paranoia or hypersensitivity
Unexplained headaches or stomach pain
Head injury history
Family history of aggression or violence
Intrusive dark thoughts
Memory lapses or forgetfulness
This type is marked by intense fluctuations in mood, associated with excessive activity in the basal ganglia and limbic areas. These “emotional seizures” appear in cycles and may be related to conditions like bipolar disorder, panic attacks, or PMS-related mood swings.
Symptoms (in addition to baseline anxiety/depression) may include:
Episodes of elevated or severely low mood
Feeling energized on very little sleep
Grandiose thoughts or risky plans
Fast-paced speech or excessive talking
Racing thoughts
High energy bursts
Poor decision-making and risk-taking
Socially inappropriate behavior
Aggressive or irritable outbursts
Delusions or hallucinations
This type involves reduced activity in the prefrontal cortex (PFC), affecting attention, organization, and motivation, alongside increased activity in the limbic system and basal ganglia. It shares overlap with symptoms of ADD/ADHD, but brain scans help distinguish it.
In addition to anxiety/depression symptoms, look for:
Difficulty focusing or staying on task
Feeling mentally foggy or spaced out
Overwhelmed by daily responsibilities
Physical and mental sluggishness
Chronic procrastination
Ongoing boredom
Easily distracted or forgetful
Difficulty articulating emotions
Lack of empathy
Reduced motivation or drive
A variation of this type includes overall low cortical activity and high limbic/basal ganglia activity, often caused by factors like brain injury, chronic illness, infections (e.g., Lyme disease), environmental toxins, or substance abuse. Symptoms may include “brain fog,” persistent fatigue, and cognitive decline.
Significant weight loss or gain, food avoidance, vomiting, laxative use, or emotional overeating.
Recurrent physical tics, vocal outbursts, or compulsive actions like checking or organizing.