# Polysubstance Addiction Research Center (PARC)

> PARC is a NIDA P50 Center of Excellence at UC San Diego (award P50DA066459, 2026–2031). The center identifies convergent and divergent multiscale mechanisms of addiction-like behaviors across alcohol, opioid, and cocaine use disorders using genetically diverse heterogeneous stock (HS) rats, builds a One-Individual Multiscale Atlas integrating brain connectomic, transcriptomic, and gut–vagus–brain data measured in the same individuals, and serves as a national resource through the Addiction Biobank and pilot funding.

Director: Olivier George, PhD, Professor, Department of Psychiatry, UC San Diego School of Medicine. Full text of the site's scientific content: https://www.drugaddictionresearch.org/llms-full.txt

## Main sections

- [About the center](https://www.drugaddictionresearch.org/about): mission, history, the One-Individual Multiscale Atlas, funding acknowledgment
- [Research projects](https://www.drugaddictionresearch.org/research): Project 1 Brain Transcriptomics, Project 2 Brain Connectomics, Project 3 Gut–Vagus Multiomics
- [Cores](https://www.drugaddictionresearch.org/cores): Administrative, Behavioral Phenotyping, Computational & Analytical, Addiction Biobank, Pilot Projects
- [Addiction Biobank](https://www.drugaddictionresearch.org/cores/biobank): request behaviorally and genetically characterized rat samples (cocaine, oxycodone, alcohol, polydrug)
- [Pilot funding](https://www.drugaddictionresearch.org/pilot-projects): request for applications, eligibility, how to apply
- [Publications](https://www.drugaddictionresearch.org/publications): peer-reviewed papers by center investigators since 2020
- [Center members](https://www.drugaddictionresearch.org/members): administration, investigators, affiliated members, collaborators
- [News](https://www.drugaddictionresearch.org/news): news, awards, seminars, outreach, teaching
- [Join us](https://www.drugaddictionresearch.org/join-us): open positions, membership, and center meetings (subscribable calendar at https://www.drugaddictionresearch.org/parc-calendar.ics)
- [Resources](https://www.drugaddictionresearch.org/resources): behavioral models guide, HS rats, data sharing, preclinical testing services
- [Support the center](https://www.drugaddictionresearch.org/support): philanthropy and giving options
- [Contact](https://www.drugaddictionresearch.org/contact)

## Explainers (plain-language, referenced)

- [What animal models can (and can't) tell us about addiction](https://www.drugaddictionresearch.org/blog/animal-models-of-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.
- [Same disorder, two species: how the center compares rat and human data](https://www.drugaddictionresearch.org/blog/comparing-preclinical-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.
- [From rat to medicine: how a lab finding becomes an addiction treatment](https://www.drugaddictionresearch.org/blog/from-rat-to-medicine): 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.
- [The gut–brain axis: how your microbiome talks to your brain, and what it means for addiction](https://www.drugaddictionresearch.org/blog/gut-brain-axis-and-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.
- [Heterogeneous stock rats: a genetically diverse population for studying addiction](https://www.drugaddictionresearch.org/blog/heterogeneous-stock-rats): 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.
- [Is addiction a brain disease? What the science actually says](https://www.drugaddictionresearch.org/blog/is-addiction-a-brain-disease): 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.
- [Mapping the addicted brain, one network at a time](https://www.drugaddictionresearch.org/blog/mapping-brain-networks): 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.
- [How do you measure addiction in a rat? The Addiction Index explained](https://www.drugaddictionresearch.org/blog/measuring-addiction-in-the-lab): Clinicians diagnose substance use disorder with behavioral criteria. Researchers apply the same logic to animals, scoring escalation, motivation, and use despite consequences.
- [The One-Individual Multiscale Atlas: connecting genes, brain, and body in the same individuals](https://www.drugaddictionresearch.org/blog/one-individual-multiscale-atlas): 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.
- [Single-cell transcriptomics: reading the brain's gene programs, one cell at a time](https://www.drugaddictionresearch.org/blog/single-cell-transcriptomics): 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.
- [The three-stage cycle: how addiction reorganizes the brain](https://www.drugaddictionresearch.org/blog/three-stage-addiction-cycle): Binge, withdrawal, craving: the influential three-stage framework explains addiction as a repeating cycle that progressively rewires three brain systems.
- [What is a biobank, and why does addiction research need one?](https://www.drugaddictionresearch.org/blog/what-is-a-biobank): 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.
- [What is polysubstance addiction, and why study drugs together?](https://www.drugaddictionresearch.org/blog/what-is-polysubstance-addiction): 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.
- [Why do only some people become addicted?](https://www.drugaddictionresearch.org/blog/why-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.
- [Why relapse happens: the neuroscience of craving](https://www.drugaddictionresearch.org/blog/why-relapse-happens): 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.

## Key facts

- Most people who use drugs never develop addiction; the center studies why some do, using individual-differences designs in genetically diverse rats.
- Addiction-like behavior is scored with the Addiction Index (escalation, motivation, use despite negative consequences), modeled on DSM-5 criteria, plus analgesia, hyperalgesia, tolerance, and incentive salience.
- The Addiction Biobank holds roughly 40,000 specimens from nearly 4,000 behaviorally characterized, whole-genome-sequenced rats and has supported 75 external collaborations.
- Contact: lmaturin@health.ucsd.edu (Lisa Maturin, Administrative Coordinator and Addiction Biobank Manager).