Our Team

Executive Team

Joseph R. Turner, JD, is the co-founder and current President/CEO of EXPONENTS, Inc., in New York City. EXPONENTS is the first known harm reduction substance…
Executive Vice President/CFO
Regina Edwards is the Executive Vice President & Chief Financial Officer of Exponents, Inc. She has been with the organization for 23 years and oversees…
Executive Vice President/COO
Samantha Lopez has been with EXPONENTS for over fifteen years first as Director of Development & Contracts then Director of Quality Assurance and Chief Administrative…


As a collective, we make sure to work as hard as possible to produce high-quality results in a loving and supportive environment. We believe that a team is only as strong as its weakest link, and we are proud to say that everyone we work with is leaders in their own right.


Viola Varner, LSMW, CASAC

Assistant Director of Drug Treatment

Athena Thomas

Human Resource Coordinator 

Tawana Rowser-Brown, PhD, MSW, Master-CASAC, CRPA, CARC

Director, Exponents Center for Personal & Professional Development

Donald Powell, MhS

Senior Director of Programs and Development

Yvonne Soto, MBA, CASAC-T

Director of Special Projects

Juan Jordan, CRPA

Director, Recovery Support Services

Shayra Vega, CASAC

Assistant Director, Judith Loeb Chiara Recovery Center

Dana Diamond, CASAC

Director of Health Services

Victor Velazquez, CASAC

Director of Trainings

Dianco Holder, CASAC II, R.C.A. Trainer of Trainers, Recovery Coach

Assistant Director of Trainings

Frank Perez

Director of Data Systems

David Wilson

IT Manager

Alexandra Spinks

Individual Giving & Fundraising Manager

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