Skip to Content

Causes of Poor Concentration - Not Just ADHD

image

"I can't concentrate, is it ADHD?" Poor concentration has numerous causes including sleep, stress, depression, nutrition, environment, not just ADHD. Before self-diagnosing hastily, check other possibilities first.

Related articles: What is ADHD? | How to Improve Focus Without Medication

What is Concentration?​

Types of Attention​

1. Sustained Attention

  • Maintaining focus on one thing for a long time
  • Studying, reading, work
  • Weakest in ADHD

2. Selective Attention

  • Selecting only necessary information
  • Listening to conversation in noise
  • Focusing in distracting environment

3. Divided Attention

  • Processing multiple things simultaneously
  • Multitasking
  • Talking while driving

4. Shifting Attention

  • Switching between tasks
  • Flexible thinking
  • When topics change in meetings

Brain Functions Needed for Concentration​

Frontal Lobe

  • In charge of executive functions
  • Planning, organizing, inhibition
  • Reduced function in ADHD

Dopamine System

  • Reward circuit
  • Motivation
  • Also reduced in depression

Norepinephrine

  • Maintaining arousal
  • Attention control
  • Decreases with sleep deprivation

Causes of Poor Concentration Other Than ADHD​

1. Sleep Deprivation​

Most Common Cause

Symptoms

  • Daytime sleepiness
  • Foggy feeling
  • Concentration drops sharply
  • Increased irritability
  • Memory decline

Impact of Sleep Deprivation

4-5 hours of sleep per day
= Blood alcohol content 0.08% (drunk driving level)
= 30-40% decline in cognitive function

Distinguishing from ADHD

  • ADHD: Can't concentrate even with enough sleep
  • Sleep deprivation: Recovers with enough sleep
  • Symptoms disappear when sleep debt is repaid

Solutions

  • 7-9 hours of sleep (adults)
  • Regular bedtime
  • Keep bedroom dark and cool
  • Turn off screens 1 hour before bed
  • No caffeine after afternoon

2. Chronic Stress​

Brain Overload

Symptoms

  • Mind feels cluttered
  • Can't focus on one thing
  • Constant worrying
  • Tension, anxiety
  • Physical symptoms (headaches, indigestion)

Cortisol's Impact

  • Excessive stress hormone secretion
  • Hippocampus damage (memory decline)
  • Prefrontal lobe function suppression
  • Decreased concentration, judgment

Distinguishing from ADHD

  • ADHD: Lifelong symptoms
  • Stress: Worsens during specific periods
  • Recovers when stress is relieved

Solutions

  • Identify and remove stress sources
  • Meditation, yoga
  • Exercise (best for stress relief)
  • Adequate rest
  • Counseling when necessary

3. Depression​

Hidden Concentration Killer

Symptoms

  • No motivation
  • Everything feels bothersome
  • Thinking slows down
  • Can't make decisions
  • Decreased concentration
  • Memory decline

Depression vs ADHD

  • Depression: Recent onset, accompanied by low mood
  • ADHD: Since childhood, independent of mood

Can Coexist

  • ADHD + depression can occur together (30-50%)
  • Frustration from ADHD → depression development
  • Both need treatment

Solutions

  • Psychiatric consultation
  • Antidepressants (when necessary)
  • Cognitive behavioral therapy
  • Regular exercise (effective for depression)
  • Get sunlight

4. Anxiety Disorders​

Worry That Consumes Concentration

Symptoms

  • Constant worrying
  • "What if...?"
  • Heart palpitations
  • Restlessness
  • Trying to concentrate → worries emerge

Mechanism of Anxiety

  • Threat detection system overactivation
  • Amygdala overactivity
  • Frontal lobe resources consumed by worrying
  • No capacity left to focus on tasks

Distinguishing from ADHD

  • ADHD: Can't concentrate even without worry
  • Anxiety: Can't concentrate because of worry
  • Concentration recovers when anxiety is resolved

Solutions

  • Cognitive behavioral therapy (CBT)
  • Mindfulness, meditation
  • Breathing exercises
  • Anti-anxiety medication when necessary
  • Set aside specific worry time

5. Nutritional Deficiency​

Brain Needs Nutrients

Iron Deficiency

  • Fatigue, poor concentration
  • Common in women (menstruation)
  • Confirm with blood test
  • Improves with iron supplements

Vitamin B12 Deficiency

  • Needed for energy production
  • Risk for vegetarians
  • Memory, concentration decline
  • Supplements effective

Omega-3 Deficiency

  • Component of brain structure
  • Related to concentration, memory
  • Fish, nuts
  • Also has auxiliary effect for ADHD

Protein Deficiency

  • Raw material for dopamine, norepinephrine
  • Concentration drops when skipping breakfast
  • Get enough protein

Solutions

  • Balanced diet
  • Blood test (check deficiency)
  • Supplements when necessary
  • Always eat breakfast

6. Hypothyroidism​

Slowed Metabolism

Symptoms

  • Fatigue, lethargy
  • Decreased concentration, memory
  • Very sensitive to cold
  • Weight gain
  • Depression

Confused with ADHD

  • Similar symptoms
  • Distinguish with blood test (TSH, T3, T4)
  • Recovers with thyroid hormone intake

Solutions

  • Internal medicine blood test
  • Thyroid hormone treatment
  • Iodine intake (seaweed)

7. Medications and Alcohol​

Substances That Interfere with Concentration

Excess Caffeine

  • Anxiety, restlessness
  • Sleep interference
  • Actually decreases concentration
  • Dependence

Alcohol

  • Reduced sleep quality
  • Poor concentration next day
  • Chronic drinking → cognitive decline

Medication Side Effects

  • Antihistamines (drowsiness)
  • Pain relievers (decreased concentration)
  • Blood pressure medication (some)
  • Antidepressants (initially)

Solutions

  • Less than 200mg caffeine per day (2 cups of coffee)
  • Reduce alcohol
  • Consult doctor about medication side effects
  • Consider prescription change

8. Digital Overload​

"Digital ADHD"

Modern Concentration Crisis

  • Short-form content (TikTok, Reels, Shorts)
  • Average attention span: 8 seconds (2000: 12 seconds → 2023: 8 seconds)
  • Forced multitasking
  • Notification addiction

Brain Changes

  • Conditioned to instant rewards
  • Difficulty tolerating delayed rewards
  • Lowered dopamine baseline
  • Difficult to do tasks requiring "real" concentration

Symptoms

  • Can't watch videos for more than 2 minutes
  • Can't read books
  • Scroll while reading long texts
  • Constantly checking phone
  • Can't tolerate boredom

Distinguishing from ADHD

  • Digital ADHD: Worsened in recent years
  • ADHD: Persistent since childhood
  • Can recover with digital detox

Solutions

  • Digital detox (1 hour screen-free per day)
  • Delete short-form apps
  • Turn off notifications
  • Increase reading time
  • Practice tolerating "boredom"

9. Chronic Pain​

Pain Consumes Attention

Mechanism

  • Resources consumed processing pain signals
  • Prefrontal lobe function decline
  • Difficulty maintaining concentration

Symptoms

  • Distracted by pain during tasks
  • Constant discomfort
  • Irritability, sensitivity
  • Sleep interference

Solutions

  • Treat pain cause
  • Pain relievers (when necessary)
  • Physical therapy
  • Chronic pain management program

10. Premenstrual Syndrome (PMS)​

Women's Cyclical Concentration Decline

Symptoms

  • 1-2 weeks before menstruation
  • Decreased concentration, memory
  • Irritability, depression
  • Fatigue

Hormonal Changes

  • Estrogen, progesterone fluctuation
  • Serotonin decline
  • Brain function impact

Solutions

  • Track menstrual cycle
  • Avoid important tasks (if possible)
  • Exercise, dietary control
  • Consult gynecology if severe

When Should You See a Doctor?​

High ADHD Possibility​

If all of these apply, see psychiatry

  • Symptoms since before age 12
  • Appears in multiple situations (school+home+work)
  • Persists for more than 6 months
  • Can't concentrate even with enough sleep
  • Can't concentrate even without stress
  • Difficult to start even interesting tasks
  • Seriously interferes with daily life

High Possibility of Other Causes​

Resolve these first

  • Sleep: Not getting enough sleep?
  • Stress: Any major events recently?
  • Depression/Anxiety: Constantly feeling depressed or anxious?
  • Nutrition: Picky eating or nutritional imbalance?
  • Digital: Screen time more than 4 hours per day?
  • Health: Any chronic diseases?

After 1-2 months of improvement efforts

  • Symptoms still persist
  • No improvement at all
  • Serious interference with daily life
  • → Then consult professional

Choosing Professionals​

Internal Medicine/Family Medicine

  • Sleep, thyroid, nutrition tests
  • Health checkup
  • Check for chronic diseases

Psychiatry

  • ADHD diagnosis
  • Depression, anxiety disorder diagnosis
  • Medication treatment
  • Mental illness differentiation

Psychological Counseling Center

  • Stress management
  • Cognitive behavioral therapy
  • Lifestyle improvement
  • Non-medication approach

Self-Check Checklist​

If you've experienced poor concentration in the last 3 months

Step 1: Basic Health Check​

□ Average sleep time more than 7 hours per day?
□ Exercise regularly? (3+ times per week)
□ Eating balanced meals?
□ Screen time less than 4 hours per day?
□ No chronic diseases?

2 or fewer checked: Improve lifestyle first

Step 2: Mental Health Check​

□ Have you had major stress recently?
□ Has depressed mood persisted for more than 2 weeks?
□ Do you worry constantly?
□ Are you very irritable?
□ Do you lack motivation?

2 or more checked: Psychiatric consultation recommended

Step 3: ADHD Suspicion Check​

□ Have you had concentration problems since childhood? (Before age 12)
□ Do symptoms appear at school and at home?
□ Persisting for more than 6 months?
□ Can't concentrate even with enough sleep?
□ Do you frequently lose things?
□ Do you act impulsively?
□ Is it hard to sit still?
□ Difficult to complete tasks to the end?

6 or more checked: ADHD possibility, psychiatric diagnosis needed

Concentration Improvement Priorities​

Priority 1: Lifestyle (Everyone)​

Can Start Immediately

  • 7-9 hours of sleep
  • Regular exercise
  • Healthy diet
  • Digital detox
  • Stress management

Evaluate after 2-4 weeks

  • If improved: Continue maintaining
  • If not: Move to priority 2

Priority 2: Health Checkup​

Internal Medicine Blood Test

  • Iron, vitamin B12
  • Thyroid hormones
  • Blood sugar
  • General health status

If problems found

  • Treat cause
  • Supplement nutrients
  • Re-evaluate after 1-2 months

Priority 3: Mental Health Evaluation​

If depression/anxiety symptoms present

  • Psychiatric consultation
  • Consider counseling therapy
  • Medication treatment when necessary

After improvement

  • Check if concentration also improves
  • If still problematic, ADHD evaluation

Priority 4: ADHD Evaluation​

After excluding other causes

  • Comprehensive psychiatric evaluation
  • Psychological testing
  • Accurate diagnosis
  • Treatment plan

Related: What is ADHD? | ADHD Medication Treatment

Importance of Integrated Approach​

When Multiple Causes Overlap​

Reality

  • ADHD + sleep deprivation
  • Depression + digital overload
  • Stress + nutritional deficiency
  • Multiple causes acting simultaneously

Approach

  • Improve all factors together
  • Set priorities
  • Solve one by one
  • Get professional help

Example: College Student's Poor Concentration​

Case

Symptoms: Can't concentrate in class, procrastinates assignments, declining grades

Cause Analysis:
- Sleep: 4-5 hours (insufficient)
- Stress: Grade worries (high)
- Digital: Watching short-form content 6 hours per day (excessive)
- Exercise: None
- Diet: Irregular, picky eating

Solution Order

  1. Increase sleep to 7 hours (1 week)
  2. Delete short-form apps (1 week)
  3. Regular meals (1 week)
  4. Start exercising (3 times per week)
  5. Evaluate after 4 weeks
    • Improved: Continue maintaining
    • Not improved: Professional consultation

Conclusion​

Poor concentration has numerous causes, not just ADHD. Don't self-diagnose hastily, check lifestyle habits first, and get professional help when needed.

Key Points

  1. Not just ADHD - Various causes including sleep, stress, depression, nutrition
  2. Lifestyle first - 80% can be resolved with lifestyle improvement
  3. Give it time and observe - Evaluate after 2-4 weeks of improvement efforts
  4. Professional diagnosis needed - No self-diagnosis, accurate differentiation
  5. Integrated approach - Solve multiple causes together

No Self-Diagnosis

  • "Can't concentrate" ≠ ADHD
  • Exclude other causes first
  • Professional accurate diagnosis
  • Risk of hasty medication

Priorities

  1. Sleep, exercise, diet (2-4 weeks)
  2. Health checkup (when necessary)
  3. Mental health evaluation (depression/anxiety)
  4. ADHD evaluation (last)

When to see doctor?

  • Doesn't improve even with lifestyle changes
  • Persists for more than 6 months
  • Serious interference with daily life
  • Symptoms since childhood

Message of Hope

  • Most causes are solvable
  • Lifestyle improvement has great effect
  • Even ADHD is treatable
  • Concentration can be improved

"Not everyone who can't concentrate has ADHD. There are countless causes including sleep, stress, depression, nutrition. Don't hastily self-diagnose, check one by one. Most cases improve significantly with just lifestyle improvements."

Accurately identifying the cause of your poor concentration is the first step. You need to know the cause to find the right solution.