Mechanism

Dopamine

Catecholamine neurotransmitter synthesized from tyrosine/L-DOPA in the substantia nigra and ventral tegmental area. Regulates motivation, anticipatory pleasure, reward learning, voluntary movement, and executive functions. Its deficit causes Parkinson's; its chronic dysregulation is associated with addictions, ADHD, and some traits of obsessive rumination.

Effect by goal · level of evidence

Motivation and pleasure

modulates Very high physiology (A)

Reward circuit

Dopamine is not the 'pleasure neurotransmitter' but the neurotransmitter of anticipating pleasure and of motivation to act. People addicted to hyperdopaminergic stimuli (social media, pornography, sugar, gambling) show downregulation of D2 receptors.

View the study (review) →

Parkinson's

reduces Very high physiology (A)

Parkinson's target

The progressive death of dopaminergic neurons in the substantia nigra causes Parkinson's. L-DOPA is the standard replacement treatment; dopamine agonists also act.

View the study (review) →

ADHD

modulates Very high physiology (A)

ADHD target

Stimulants (methylphenidate, amphetamines) act by increasing dopamine and norepinephrine in the prefrontal cortex, improving sustained attention.

View the study (review) →

Anxiety and rumination

modulates Moderate hypothesis (A)

Rumination pathway

People with anxious obsessive rumination often show hyperactivity in ventral striatal dopaminergic circuits. 'Anticipatory anxiety' (before a task) is dopamine in warning mode.

Information, not medical advice. Scientific evidence reflects the quality of the studies.