Causes

1. Overview — Overall picture of causes

Most mental–brain conditions or disorders do not arise from a single cause, but are the result of a multi-layered system that operates together continuously at biological, psychological, and environmental levels around the individual. At the most basic level, we view the origin of symptoms as a “risk architecture” embedded in the body and brain from birth, combined with neurodevelopment from childhood, learned behaviors, emerging personality patterns, daily-life stress, and relational experiences that leave emotional wounds or cumulative pressure.

This is a multi-factor model perspective, which explains that disorders do not emerge suddenly out of nowhere, but from “multiple layers of variables” that gradually squeeze the emotion- and thought-regulation systems until they collapse. For example, a genetic makeup that makes the brain more sensitive to stress is combined with a prefrontal cortex that does a poor job controlling impulses, and is then further overloaded by chronic stress in the family or at work. When these factors line up and accumulate, the brain can enter a state of imbalance and begin to express clear emotional, behavioral, or cognitive symptoms.

Explaining things through this lens also helps us understand why different patients present with different symptom profiles, even when they share the same diagnosis. The causal architecture driving symptoms is different for each person. For instance, some have strong biological predispositions, some are driven more by psychological factors, some are triggered by acute stress, some are shaped by long-term trauma, and some develop symptoms from the cumulative effect of dozens of “small” factors working together.

Therefore, understanding causes requires a holistic viewpoint that considers the integration of:
Biological vulnerability × Neurodevelopment × Cognitive-emotional patterns × Environment × Stress × Trauma
gradually converging until a full-blown symptom pattern emerges.

In short, there is “no single cause”, and no factor works in isolation. Every factor is a gear in a larger mechanism, turning in relation to the others. When these gears start turning out of sync at the same time, the balance of brain–body–mind becomes distorted and is eventually expressed as the conditions or symptoms we see in clinical practice.

You can open any article with this framework, because it is a narrative that is accurate, trustworthy, and consistent with the overall picture of modern research in neuroscience and clinical psychology.

---

2. Biological & Genetic Factors — Genetics and biological systems

Biological and genetic factors form one of the most fundamental foundations of risk for almost all forms of mental imbalance, because they represent the “baseline temperament of the brain” that a person is born with. This baseline shapes how the body and brain respond to stress, pressure, and life experiences.

These factors do not guarantee that a person will develop a disorder, but they significantly increase the probability and sensitivity to various triggers.

● Heritability — Genetic risk

Research from twin studies, family studies, and genome-wide association studies (GWAS) clearly shows that nearly all psychiatric conditions carry a degree of genetic loading, whether it is depression, anxiety, ADHD, OCD, PTSD, bipolar disorder, personality disorders, or even perinatal and postpartum mental disturbances.

Core components of heritability include:

• Increased risk in first-degree relatives, such as parents, children, and siblings.
• If one identical twin (monozygotic) has a given condition, the other twin has a markedly higher probability than a fraternal twin.
• Heritability for some disorders can be as high as 40–80% (depending on the condition).
• Genetics determine the baseline that essentially answers the question: “How sensitive is this brain to stress/hormones/emotional shifts?”

Thus, genetics do not tell us that a person will become ill, but rather that “if exposed to the same level of triggers, this brain will carry a heavier load than another brain by default.”

---

● Candidate Genes — Genes influencing emotional balance and neural systems

Research in molecular genetics has found that genes related to neurotransmitters, stress regulation, emotional circuits, and brain rhythms play major roles. For example:

1. Dopamine system genes
Involved in motivation, reward, pleasure, impulse control, and executive function.
Dysregulation in dopamine pathways is commonly seen in ADHD, bipolar disorder, and addiction.

2. Serotonin system genes
Affect mood, sleep, and emotional stability.
Genes in the serotonin system, such as 5-HTTLPR, are often associated with stress sensitivity and depression.

3. Glutamate and GABA genes
These two systems are the main controllers of the excitatory–inhibitory balance in the brain.
Imbalances here are linked to anxiety, OCD, bipolar disorder, and psychosis.

4. Genes affecting the HPA axis
These influence cortisol and the stress response.
People with an HPA axis that is more reactive than average tend to respond to stress more intensely than others.

5. Genes shaping emotional regulation
These influence how emotions are interpreted, how social signals are read, and how behavior is inhibited or controlled.

6. Circadian rhythm genes
Genes that govern the biological clock.
Dysfunction here is often found in seasonal depression, bipolar cycling, or postpartum mood disturbances.

Key point: Modern research indicates that there is no single “disease gene” that directly causes a disorder. Instead, risk is shaped by the combined effect of many genes—a polygenic pattern that increases or decreases vulnerability.

---

● Biological Vulnerability — Biological fragility or sensitivity

This refers to a set of bodily and neural baselines that make some brains less resilient to stress than others, even when exposed to the same events. These include:

● Neurochemical imbalance

• Dopamine too low/too high or out of sync.
• Serotonin instability.
• Excess norepinephrine under stress.
• Excess glutamate (excitotoxicity).

● Hormonal fluctuations

• Chronically elevated cortisol.
• Fluctuating estrogen/progesterone (common in PMS, PMDD, postpartum, and menopause).
• Thyroid dysregulation (strongly linked to mood).

● Immune activation / inflammation

Many studies suggest that some forms of depression, anxiety, and brain fog are associated with:

• Low-grade inflammation
• Cytokines that increase brain circuit sensitivity and reactivity.

● Abnormally high stress reactivity
Some people are simply born with a more intense stress-response system, such as:

• Heart rate that spikes easily.
• Cortisol that surges quickly.
• A sympathetic nervous system that is overly sensitive.

This constitutes a person’s “biological identity” that shapes their long-term risk profile.

3. Brain & Neurodevelopment — Brain and neurodevelopment

● Neural Circuit Differences — Brain circuits functioning out of balance

Many mental disorders are linked more to the timing and dynamics of neural circuit activity than to gross structural damage. For example:

1. Prefrontal Cortex (PFC) — Executive control
A weakened PFC =

• Difficulty inhibiting emotions.
• Poor impulse control.
• Slow decision-making or easy distractibility.

It is like the “brain’s manager” taking an overly long vacation.

2. Amygdala — Threat detection & emotional intensity
An overactive amygdala =

• Easy panic.
• Overthinking.
• Pronounced anxiety.
• Emotional flooding.

3. Hippocampus — Memory & context
Shrinkage or poor functioning =

• Vivid recall of negative experiences.
• Impaired recall of context that would normally reduce fear.
• Increased risk of PTSD or generalized anxiety.

4. Default Mode Network (DMN)
When the DMN is overactive =

• Involuntary repetitive thinking about the same issues.
• Feelings of worthlessness.
• Continuous, uncontrollable rumination.

Commonly found in depression and anxiety disorders.

5. Salience Network
If this network is out of sync =

• Focus lands on the wrong cues.
• Threat is overinterpreted.
• Heightened sensitivity to irrelevant stimuli.

6. Executive Control Network
When weakened =

• Difficulty planning.
• Broken task-prioritization systems.
• Poor behavioral inhibition.

All these circuits are interconnected. When one becomes dysregulated, the others must work harder to compensate, which can eventually contribute to symptom formation.

---

● Neurodevelopmental Trajectory — Brain development from childhood onward

The brain is not an organ that “stops developing” at birth. It continually builds, prunes, and reorganizes its networks until around age 25. This makes childhood experiences extremely powerful.

Key factors in neurodevelopment include:

• Caregiving style (attunement, secure attachment, neglect).
• Exposure to childhood stress.
• Learning environment.
• Nutrition during pregnancy and early childhood.
• Toxins such as cigarette smoke and alcohol.
• Perinatal hypoxia (low oxygen at birth).
• Premature birth.
• Infections during pregnancy.

These factors determine:

• Whether emotional circuits become hypersensitive or remain stable.
• Whether fear circuits become over-responsive.
• Whether emotion-regulation systems (especially the PFC) reach full maturity.

Children who grow up in chronically unsafe environments often develop brain circuits with high sensitivity, leading them to “read the world” as threatening and expect negative outcomes automatically in adulthood.

---

● Physiological Systems — Bodily systems that affect mood and emotion

1. HPA axis dysregulation
This refers to a dysregulated cortisol system:

• Strong, exaggerated responses to stress.
• Slow recovery back to baseline.
• Waking with morning anxiety.
• Feeling completely drained by evening.
• Emotional rhythms out of sync.

Seen in: depression, anxiety, PTSD, postpartum disturbances.

2. Autonomic Nervous System (ANS) — Sympathetic dominance
If the sympathetic branch outweighs the parasympathetic branch =

• Rapid heart rate.
• Cold hands.
• Easy anxiety.
• Shallow or disrupted sleep.
• Heightened startle reflex.

3. Circadian rhythm & sleep-wake system
When the biological clock is disrupted =

• Mood switches easily.
• Mental fatigue.
• Executive function declines.
• Increased risk of depression and bipolar cycling.
• Higher frequency of postpartum mood swings.

---

4. Psychological Factors — Mental processes, cognition, and behavior

Psychological factors are the “software layer of the brain” that determine how a person interprets situations, what kind of emotional response emerges, and what form their behavior takes. Even though biology and genetics lay down the risk foundation, cognition (thinking), personality, and learning patterns shape the direction in which that risk is either “activated” or remains latent.

Put simply: biology is the hardware, while the psychological layer is the operating system running on the brain. This operating system can either buffer or amplify risk far more than we might expect.

---

● Core Beliefs & Cognitive Patterns — Core beliefs and ways of interpreting the world

Core beliefs are the primary lenses through which a person views the world, other people, and themselves. If these beliefs are formed in unsafe or distorted environments in childhood, they become an “emotional template” that leads the brain to interpret surrounding events in excessively negative ways. For example:

• Negative self-schema
  “I am worthless.”
  “I am bound to fail.”
  “No one truly understands me.”

• Interpretation bias
  Translating neutral signals into threats, such as hearing a loud noise and immediately assuming danger.

• Cognitive distortions
  For example, all-or-nothing thinking, mind-reading, catastrophizing.

• Rumination / Overthinking
  Repetitively cycling through problems, analyzing them without end, which prolongs and intensifies symptoms.

When these cognitive patterns operate daily, the brain becomes trained to “expect the negative” automatically—similar to an AI system fed biased data until its underlying algorithm skews heavily toward negative predictions.

---

● Personality Traits — Baseline traits that increase risk or protect the brain

Personality is not destiny, but it has a powerful impact on how a person copes with stress. For example:

• High Neuroticism
• Heightened sensitivity to emotional stimuli.
• Minor negative experiences can trigger disproportionately strong emotions.
• Increased vulnerability to depression and anxiety.

• Low Conscientiousness
• Poor ability to plan and organize.
• Lack of stable routines.
• Mental energy constantly drained by life chaos.

• Maladaptive Personality Traits
• Avoidance-based coping: avoiding problems → problems grow larger.
• Perfectionism: unrealistically high self-expectations become a chronic burden.
• Impulsivity: overly rapid decision-making → damage to work and relationships.
• Dependency: emotional stability is overly dependent on external people or conditions.

These personality features create additional “push” on an already fragile emotional system, especially under conditions of chronic stress.

---

● Behavioral Patterns — Behaviors that reveal the internal emotional structure

Behavior is the external expression of internal emotional processes. The brain generates behaviors to help us survive, but sometimes these survival strategies make things worse. For example:

• Avoidance
• An instinctive self-protective mechanism.
• Prevents exposure to triggers → fear circuits never down-regulate.
• Central in anxiety, OCD, trauma-related conditions, and perfectionism.

• Dependence / Reassurance-seeking
• A constant need for others to confirm that things are okay.
• Undermines self-confidence over the long term.

• Self-regulation deficits
• Inability to regulate emotions.
• Difficulty regulating behavior.
• Higher risk of impulsive decisions and emotional outbursts.

• Compensatory behavior
• Using sweets, alcohol, gaming, shopping, etc. to numb or cover up emotions.
• Creates new problems layered on top of the original issues.

---

● Learning History — Learning history and conditioning
The human brain learns from family models starting in early childhood. For example:

• Growing up with highly anxious parents → the brain learns that anxiety is the baseline state.
• Growing up with violence → the brain calibrates the threat system to be hyper-reactive.
• Growing up with constant criticism → the brain internalizes the feeling: “I am always at fault.”

Reinforcement patterns (reward and relief) are also crucial:

• Avoiding something and then feeling relief = the brain learns that avoidance is the route to safety.
• Throwing a tantrum and getting what you want = the behavior is rewarded and strengthened.
• Displaying intense emotion and having others give in = the brain encodes this pattern.

All of these combine to form an emotional blueprint that continues to influence a person well into adulthood.

---

5. Environmental Factors — Environment, lifestyle, and social context

The environment is the “external pressure field” that shapes mental states—whether it is the home we grew up in, the people we live with, the job we do, or the society surrounding us. Environmental factors can act both as protective factors and as triggers.

---

● Family Environment — Family system and emotional climate

Family relationships are one of the primary determinants of how the emotional system develops. For example:

• Families with chronic conflict → children calibrate their stress systems to a high baseline.
• Families with over-controlling parenting → children develop chronic fear of making mistakes.
• Families that neglect or ignore → children develop a core sense of worthlessness.
• Families with no emotional attunement → emotional regulation becomes difficult in adulthood.
• Families that constantly compare children → internalized feelings of inferiority.

The family essentially acts as a “factory that manufactures the brain’s default response patterns to life.”

---

● Social & Interpersonal Factors — Society and relationships

Our social world profoundly shapes emotional architecture. Examples:

● Bullying / Social exclusion

• Calibrates the brain’s threat-detection system to a hyper-alert level.
• Creates a self-schema of “I am unwanted.”

● Relationship conflict

• Unstable or unsafe relationships → high stress load.
• Gaslighting and manipulation → erosion of one’s sense of self.

● Social isolation

• The human brain is built for connection.
• Lack of connection → dopamine/oxytocin circuits “dry up.”
• Leads to chronic low mood and emotional flatness.

---

● Lifestyle & Daily Stressors — Lifestyle and everyday stress

These factors are often overlooked, yet they are constant impacts on the brain every hour of daily life:

● Sleep disturbance

• Too little sleep = emotional fragility.
• Disrupted circadian rhythm = the brain mis-times its interpretation of events.
• Pushing oneself through exhaustion = cortisol remains elevated throughout the day.

● Nutrition

• Poor nutrition = the brain has fewer raw materials to produce neurotransmitters.
• Processed foods = increased inflammation.
• Rapid blood sugar spikes and crashes = mood swings and irritability.

● Work overload

• Excessive workload → high allostatic load.
• Too much multitasking → PFC exhaustion and eventual breakdown.

● Environmental toxins

• Pollution, poor air quality, and chemicals → increased inflammation and oxidative stress.

● Financial stress

• Financial instability → the amount of stress the emotional system must process grows many times over.

---

● Cultural Expectations — Cultural context that presses on the mind

In some societies, cultural expectations exert more psychological force than even family-level stress. Examples:

• Rigid gender roles → chronic internal pressure.
• Perfectionistic social values → children grow up with strongly perfectionistic mindsets.
• Success = personal worth → the brain internalizes this pressure instantly.
• Appearance matters more than substance → higher anxiety in people who are prone to self-comparison.

Culture functions like a “rulebook of the game” that the brain must learn and survive under.

---

6. Trauma & Stress — Trauma and chronic stress

Trauma and chronic stress are among the most powerful causal factors in the development of emotional, cognitive, and behavioral disorders in adulthood. The human emotional system is designed to “remember threat” more than “remember safety and happiness” as a survival mechanism. As a result, negative experiences—especially those that are repeated or occur during periods when the brain is still developing—become deeply embedded in the nervous system and shape long-term response patterns to the world.

Trauma is not limited to dramatic, acute events. It also includes accumulated stress from unsafe relationships, chronic pressure, and emotional neglect—factors that often inflict serious damage on brain circuits without the person even realizing that what they went through counts as trauma.

---

● Acute Trauma — Sudden, acute trauma

This type of trauma arises from severe, emotionally shocking events that strike suddenly and push the nervous system into an “acute threat response” mode.

Examples:

• Serious accidents.
• Natural disasters.
• Physical or sexual violence.
• Being assaulted in front of others.
• Sudden and unexpected loss of a loved one.
• Betrayal trauma: being deeply betrayed by someone you trusted.

Effects on the brain:

• Amygdala hyperactivation → the brain overinterprets threats.
• Hippocampal fragmentation → memories are broken into fragments with unclear sequence (typical PTSD memory).
• Prefrontal cortex shutdown → difficulty making decisions, forgetfulness, and easy anxiety.
• The fight–flight–freeze system becomes activated and may gradually turn into the new baseline.

Acute trauma is like an “instant crack” in the emotional system which, if never healed, slowly spreads and solidifies into chronic psychopathology later on.

---

● Chronic Interpersonal Stress — Chronic stress from pressured relationships

This is the most common yet most overlooked form of trauma. It does not come from a single intense event but from relationships in everyday life that “erode” the psyche little by little, creating micro-traumas over and over until the brain breaks down.

Examples:

• Being in a relationship that is constantly tense, unstable, or on the brink of rupture.
• Persistent criticism.
• Being ignored or emotionally neglected.
• Living with a partner who controls or manipulates (gaslighting, blame-shifting).
• Growing up or living in a home with no emotional safety.
• Families with silent hostility (fighting through cold silence rather than words).

Effects on the brain:

• The brain calibrates the threat system to be abnormally sensitive.
• The PFC works overtime to regulate emotions → eventually becomes exhausted and regulation fails.
• Feelings of guilt, shame, and insecurity solidify into deeply embedded self-schemas.
• The brain becomes trained to “expect rejection” automatically.

Chronic interpersonal stress is often the most painful form of trauma because it unfolds in spaces that were supposed to be the safest: the home, romantic relationships, family, close attachments.

---

● Early-Life Adversity — Childhood adversity

Negative experiences in childhood (ACEs) include:

• Being rejected.
• Domestic violence.
• Parents constantly fighting.
• Being compared to siblings.
• Lack of emotional attention.
• Growing up in an unstable environment.
• Emotionally unstable parents.
• Being devalued, criticized, or shamed.
• Authoritarian parenting (rigid, harsh, controlling).
• Or neglectful parenting (emotional/physical neglect).

Effects on development:

• The HPA axis is set to be “easily triggered into fear.”
• The amygdala grows or becomes more sensitized than normal.
• The hippocampus fails to fully develop due to chronic stress hormones.
• Self-schemas are mis-set from childhood, e.g., “I have no value.”
• Attachment styles become disordered: anxious, avoidant, or disorganized.

Early adversity is like programming the brain to grow up in “overprotective survival mode”, even long after the actual environment is no longer dangerous.

---

● Developmental Trauma — Trauma extended across developmental stages

Unlike acute trauma, which happens once, developmental trauma involves prolonged exposure to distressing conditions during childhood—such as excessive control, living in unpredictable home environments, or repeated criticism. These can carve deeper and longer-lasting grooves into the psyche because they become woven into the process of identity formation.

Consequences:

• Damage to personal confidence.
• Distorted reading of social signals.
• Increased risk for anxiety, depression, BPD, and complex PTSD (CPTSD).
• Fragmentation of the sense of self into disconnected parts.

This is the kind of trauma that teaches the brain that love = danger and closeness = pain.

---

● Allostatic Load — Accumulated stress that gradually breaks the system

Allostatic load is the “total amount of stress the emotional system has to carry” over the long term. It can come from:

• Heavy workloads.
• Tight finances.
• Family problems.
• Unstable relationships.
• Chronic sleep deprivation.
• Social pressure.
• Caring for ill family members.
• Caregiving responsibilities with no time to rest.
• Lack of nights in which the brain can truly recover.

When stress is never discharged or processed, the emotional regulation system is slowly burned out. The result:

Consequences of allostatic overload:

• The brain becomes unusually fatigued.
• Mood swings become frequent.
• Memory declines.
• Decision-making becomes more difficult.
• PFC function declines → behavioral control becomes harder.
• The amygdala expands its influence → excessive worry, hypervigilance to sounds and cues.
• The immune system weakens.
• Increased risk of depression and burnout.

This is a form of stress that does not require any single traumatic event,
yet it can break the emotional system for years or even a lifetime if not addressed.

---

● Interaction Effects — When Trauma × Stress × Biology converge

The most important point is that trauma and stress do not act alone. They:

• Activate brain circuits already vulnerable due to genetics.
• “Switch on” biological risk factors.
• Turn certain personality traits into clear clinical problems.
• Destabilize hormonal systems.
• Disrupt sleep → which in turn derails mood further.
• Reinforce avoidance-based coping strategies.

This explains why some people seem perfectly fine for many years and then, after experiencing multiple layers of stress piled on top of each other, their emotional state collapses suddenly and dramatically.

---

● Why are Trauma & Stress such powerful “symptom switches”?

Because they impact:

• Brain structure.
• Circuit connectivity.
• Hormonal (endocrine) systems.
• The autonomic nervous system (ANS).
• Sleep architecture.
• Cognitive processing and interpretation.
• Memory systems.

There is essentially no other factor that can “reshape the entire brain system” as comprehensively as trauma and chronic stress can.

---

📚 References — International-level sources
(Applicable across Biological, Brain, Psychological, Environmental, and Trauma & Stress sections)

1) Diagnostic & Clinical Frameworks
American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR). APA Publishing, 2022.

World Health Organization. International Classification of Diseases 11th Revision (ICD-11). WHO, 2019.

2) Neuroscience & Brain Development
LeDoux, J. (2015). Anxious: Using the Brain to Understand and Treat Fear and Anxiety. Viking.

Sapolsky, R. (2004). Why Zebras Don't Get Ulcers (3rd ed.). Henry Holt.

McEwen, B. S. (1998). “Protective and damaging effects of stress mediators.” New England Journal of Medicine, 338(3), 171–179.

Davidson, R. J., & McEwen, B. S. (2012). “Social influences on neuroplasticity.” Nature Neuroscience, 15(5), 689–695.

Tottenham, N., & Sheridan, M. A. (2009). “A review of adversity, the amygdala, and the hippocampus.” Development and Psychopathology, 21(1), 53–71.

3) Trauma & Stress Research
van der Kolk, B. (2014). The Body Keeps the Score. Viking.

Herman, J. L. (1992). Trauma and Recovery. Basic Books.

Yehuda, R., & LeDoux, J. (2007). “Response variation following trauma.” American Journal of Psychiatry, 164(1), 3–12.

Felitti et al. (1998). “Relationship of Childhood Abuse and Household Dysfunction to Adult Health.” American Journal of Preventive Medicine, 14(4), 245–258. (ACEs Study)

4) Emotional & Cognitive Psychology
Beck, A. T. (1979). Cognitive Therapy and the Emotional Disorders. Penguin.

Clark, D. A., & Beck, A. T. (2010). Cognitive Therapy of Anxiety Disorders. Guilford Press.

Young, J. E., Klosko, J. S., & Weishaar, M. E. (2003). Schema Therapy. Guilford Press.

5) Neurodevelopment & Early-Life Impact
Gunnar, M. R., & Quevedo, K. (2007). “The neurobiology of stress and development.” Annual Review of Psychology, 58, 145–173.

Shonkoff, J. P., & Garner, A. S. (2012). “The Lifelong Effects of Early Childhood Adversity.” Pediatrics, 129(1).

6) Brain Networks & Regulation
Menon, V. (2011). “Large-scale brain networks and psychopathology.” Trends in Cognitive Sciences, 15(10), 483–506.

Raichle, M. E. (2015). “The Brain's Default Mode Network.” Annual Review of Neuroscience, 38, 433–447.

---

🔖 Hashtags

#Neuropsychology #Neuroscience #MentalHealthEducation #PsychiatryFacts #BrainScience #TraumaInformed #StressResearch #PsychologyInsights #MindAndBrain #ClinicalPsychology #Neurobiology #BrainDevelopment #EmotionalHealth #CognitiveScience #BehavioralScience #MentalHealthAwareness