Part III Functional Medicine Approach to optimal treatment of ADHD: Serotonin/Norepinephrine modulation, Endorphin Modulation?

Serotonin vs. Dopamine: Understanding Two Powerful Brain Chemicals

When it comes to mental health, motivation, and mood, two neurotransmitters stand out: serotonin and dopamine. Though they often interact, their roles in the brain—and the body—are distinct.

Serotonin

• Role: Promotes mood stability and overall well-being.

• Functions: Regulates mood, sleep cycles, appetite, digestion, and social behavior.

• Associated Issues:

  • Low levels: Depression, anxiety, irritability.

  • High levels: Risk of serotonin syndrome (especially with certain medications).

• Key Brain Regions: Prefrontal cortex, amygdala, hippocampus.

Dopamine

• Role: Drives motivation, reward, and movement.

• Functions: Reinforces pleasure, attention, goal-seeking behavior, and fine motor control.

• Associated Issues:

  • Low levels: Parkinson’s disease, attention-deficit/hyperactivity disorder (ADHD).

  • High levels: Linked to addiction, schizophrenia, impulsivity.

• Key Brain Regions: Substantia nigra, ventral tegmental area (VTA), prefrontal cortex.

Key Differences

• Mood vs. Drive: Serotonin fosters calm and satisfaction; dopamine energizes and activates.

• Physical Impact: Serotonin influences the gut and sleep, while dopamine controls movement and reward-seeking.

• Neurochemical Balance: Serotonin helps regulate impulsivity; dopamine boosts motivation. A healthy mind depends on a delicate balance between the two.

Can Serotonin/Norepinephrine modulation help with ADHD?

Duloxetine and venlafaxine can be administered to treat symptoms of ADHD while being well tolerated. It seems that duloxetine is more potent in reducing ADHD symptoms. It can also be concluded that venlafaxine is more effective in females, and is more effective on inattentive symptoms of ADHD rather than hyperactive symptoms.

Dezfouli RA, Hosseinpour A, Ketabforoush S, Daneshzad E. Efficacy, safety, and tolerability of serotonin-norepinephrine reuptake inhibitors in controlling ADHD symptoms: a systematic review and meta-analysis. Middle East Current Psychiatry. 2024 Jan 31;31(1):8.

Dopamine vs. Endorphins: Motivation Meets Euphoria

Our brains run on complex chemistry, and two of the most influential molecules behind how we feel and act are dopamine and endorphins. Though both are tied to pleasure and well-being, their roles, triggers, and effects differ significantly.

Dopamine

• Role: A neurotransmitter that powers motivation, reward, and movement.

• Core Functions:

  • Fuels pleasure, motivation, and goal-directed behavior.

  • Regulates movement through the basal ganglia.

  • Enhances focus, learning, and anticipation of rewards.

• Key Effects: Produces short bursts of pleasure when we pursue or achieve something meaningful—whether it’s food, praise, or accomplishment.

• Associated Issues:

  • Low levels: Parkinson’s disease, ADHD, anhedonia (inability to feel pleasure).

  • High levels: Linked to schizophrenia, risk-taking behavior, and addiction.

• Primary Brain Regions: Substantia nigra, ventral tegmental area (VTA), and prefrontal cortex.

Endorphins

• Role: Natural opioids—neuropeptides that ease pain and boost mood.

• Core Functions:

  • Reduce pain and stress, often creating a euphoric state (the classic “runner’s high”).

  • Promote feelings of relaxation and well-being.

  • Support stress regulation and modulate immune response.

• Key Effects: Released during exercise, laughter, sex, or pain, helping the body cope with stress and discomfort.

• Associated Issues:

  • Dysregulation isn’t fully understood, but low levels may worsen mood disorders or pain sensitivity.

• Primary Action Sites: Throughout the brain and body, especially in pathways regulating pain and stress.

Key Differences Between Dopamine and Endorphins

Aspect	Dopamine	Endorphins
Function	Drives motivation and reward anticipation	Acts as a natural painkiller and mood stabilizer
Trigger	Released in response to rewards or goal achievement	Triggered by pain, stress, or physical activity
Effect Duration	Short bursts tied to goal-oriented behavior	Longer-lasting calming or euphoric effects
Pleasure Type	Energizing and motivating	Soothing and relieving