Blog

Understanding Addiction Science

Why do some people become addicted while others don't? What does addiction actually change in the brain, and can it be undone? Here our scientists answer the questions we hear most often, in plain English, with the evidence to back every answer.

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  TranslationCenter science 6 min read

  Same disorder, two species: how the center compares rat and human data

  Animal findings often fail to translate because the models never mirrored human diversity. PARC embeds rodent-human comparison into every project, from genes to brain networks to the gut.

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  Animal modelsMethods 7 min read

  What animal models can (and can't) tell us about addiction

  Rats will voluntarily self-administer the same drugs humans misuse, and a minority develop compulsive use. Here's how animal models work, why they're trusted, and where their limits lie.

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  TherapeuticsTranslation 6 min read

  From rat to medicine: how a lab finding becomes an addiction treatment

  The path from a discovery in animals to an approved medication runs through validated models, mechanism studies, and pre-IND data packages. Here's how the pipeline works.

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  Gut–brainMicrobiome 6 min read

  The gut–brain axis: how your microbiome talks to your brain, and what it means for addiction

  Trillions of gut microbes communicate with the brain through the vagus nerve, immune signals, and metabolites. Evidence is mounting that this axis shapes addiction.

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  GeneticsAnimal models 5 min read

  Heterogeneous stock rats: a genetically diverse population for studying addiction

  HS rats descend from eight founder strains bred together for decades, producing genetic diversity that mirrors a human population, the key to finding addiction genes.

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  Addiction basicsSociety 6 min read

  Is addiction a brain disease? What the science actually says

  The brain disease model of addiction is often caricatured on both sides. Here's what the evidence supports, and why the framing matters for treatment and stigma.

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  NeuroscienceBrain imaging 6 min read

  Mapping the addicted brain, one network at a time

  New imaging methods can capture the activity of every neuron in an intact brain, revealing how whole-brain networks reorganize during the transition to addiction.

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  Animal modelsMethods 5 min read

  How do you measure addiction in a rat? The Addiction Index explained

  Clinicians diagnose substance use disorder with behavioral criteria. Researchers apply the same logic to animals, scoring escalation, motivation, and use despite consequences.

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  AtlasCenter science 6 min read

  The One-Individual Multiscale Atlas: connecting genes, brain, and body in the same individuals

  Biology happens at many scales at once, genes, cells, circuits, organs, behavior. PARC's atlas measures all of them in the same individuals, so the scales can finally be connected.

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  GenomicsNeuroscience 6 min read

  Single-cell transcriptomics: reading the brain's gene programs, one cell at a time

  The brain contains hundreds of cell types, each running its own genetic program. Single-cell sequencing reveals how addiction rewrites those programs, cell type by cell type.

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  Addiction basicsNeuroscience 6 min read

  The three-stage cycle: how addiction reorganizes the brain

  Binge, withdrawal, craving: the influential three-stage framework explains addiction as a repeating cycle that progressively rewires three brain systems.

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  BiobankOpen science 5 min read

  What is a biobank, and why does addiction research need one?

  A biobank is a library of biological samples, but linking every sample to the donor's behavior and genome turns it into a discovery engine any lab in the world can use.

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  Addiction basicsPolysubstance 5 min read

  What is polysubstance addiction, and why study drugs together?

  Most people with a substance use disorder use more than one drug, yet most research studies one substance at a time. Here's why studying addictions together changes the science.

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  Addiction basicsIndividual differences 6 min read

  Why do only some people become addicted?

  Most people who try drugs never lose control over their use. Understanding what protects the majority, and what makes a minority vulnerable, is the central question of addiction science.

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  Addiction basicsNeuroscience 6 min read

  Why relapse happens: the neuroscience of craving

  Relapse after months of abstinence isn't a failure of willpower, it's the predictable output of brain circuits sensitized to cues, stress, and the drug itself.