Meet Our Dedicated Team

Cornerstone prides itself on being a family-run, community-focused business. Understanding the importance of community means we truly understand the importance of quality staff, for these people form the heart, the cornerstone of our community. As such, we aim to offer outstanding employee benefits to our staff, as we know we get back what we put in.

Cornerstone is proud to boast a team of the most highly skilled experts in the Substance Use and addictions field. Our staff are all fully trained in treating chemical dependency and related addictions. We also employ many people with experience of substance use disorders or addiction themselves, as we understand that those who have been through the recovery process are well equipped to help another recovering addict get to where they are. We are exceptionally proud of our 90 employees and affiliates.

Over the years we have attracted some of the most senior members of Orange County’s medical and psychological team. Many wanting to work for us because of our exceptional working conditions, camaraderie and sense of community.

Michael Stone, MD, FAAFP, ABAM, FASAM

Founder and Chief Medical Officer

Dr. Stone founded Cornerstone of Southern California in 1984 when he recognized that many addicts who needed help could not afford prolonged hospital stays. Being well versed in the treatment of addiction, he also understood that the sterile conditions of a hospital setting were so far removed from the addict’s normal life, that they were not conducive to long lasting recovery. Deciding to rectify this he set up Cornerstone of California. A place he could offer addicts seeking recovery a safe, non judgmental space where they could learn about the disease of addiction, understand their triggers, look deeper, through various empirically tested therapeutic methods, at the core reasons for their illness, while living amongst other people in a community where they could relearn basic living skills and how to socially interact. Dr. Stone has treated over 80,000 addicts and their families’ since 1969. He is well known and respected in the professional community. Dr. Stone has refused to allow Cornerstone, or himself, be pigeon holed or type cast. He has treated individuals from all walks of life. His priority is setting the individual on the path to successful, long lasting recovery, regardless of whether they are a celebrity or homeless. Dr. Stone graduated from Sheffield University Medical School, England in 1967. In 1969 he opened and directed the first in-hospital drug and alcohol treatment center in Canada. He then became Medical Director of Care Unit Hospital, Orange County, a famous psychiatric hospital. During his employment at Care Unit, the prevalence of alcoholism and drug addiction increased exponentially. Dr. Stone’s experience and ability were highly esteemed and he was asked by Betty Ford if he could, along with his team, train the Directors at the Betty Ford Center by Mrs. Betty Ford. Dr. Stone has committed himself to help people with addictive diseases for over 50 years. He has had extensive training in the field of addiction and is board certified in family medicine, board certified by the American Board of Addiction Medicine and a diplomat of the American Academy of Pain Management. Personal Life: Dr. Stone has been married since 1967. He is extremely proud of his three adult children who work full-time at Cornerstone. He enjoys the beach, loves dogs, and reads science fiction novels in his free time. He is a doting grandfather to five grandchildren.

Jiseung David Yoon, MD, MPH

Physician

Jeanette Ponce, MD

Physician

Dr. Ponce is Board-certified in Family Practice with a solid knowledge base and experience with addiction issues and medicine. She has extensive experience providing integrated primary care for patients with mental health and alcohol and drug-related issues serving as a family practice physician, internal medicine hospitalist, internist, and health educator during her career.

Dr. Ponce earned her Medical Degree from UCLA and her Bachelor of Science in Biochemistry and Cell Biology from the University of California at San Diego.

Amal Bolis Tanagho, MD

Consulting Psychiatrist

Phil Kosanovich, MBA

President & Chief Executive Officer

Phil has a senior leadership profile that spans from entrepreneurial ventures to global corporations. His experience includes consulting, operational, and executive-level roles in the behavioral health and addiction treatment industries that include co-founding and growing two residential and outpatient treatment centers. Phil is an inclusive and transformational leader with a reputation for building strong client/patient-centered teams focused on clinical excellence. He has an extensive record of success in leading companies through transitional periods of growth and creating and maintaining strong external partner relationships.

Phil’s expanded healthcare industry experience was with Landauer, where he started two subsidiary companies and led company operations in Australia and China. Prior to his 30 years in the healthcare industries, Phil was president of human resource and financial services related subsidiaries of Travelers, Equitable, Lincoln Financial Group, and Chicago Title & Trust. He has served on the executive board and in multiple leadership roles of a global human resources trade organization and elected into that industry groups Hall of Leaders. Phil has served on the boards of several healthcare-related charities and is the Chair of the Community Relations Commission in his hometown. Phil earned an MBA from DePaul University and a Bachelor of Science in Business Administration from Valparaiso University. He is in long term recovery.

Jessica Stone

Co-Founder and Executive Assistant

Since Cornerstone’s inception, Jessica Stone has been an integral component of the family business. Co-founding it in 1984 with Michael, she has tirelessly dedicated her life to the improvement of recovery outcomes for thousands of addicts.

Personal life:

Born in India, she grew up in the UK where she met and married Dr. Stone in 1967.

Jessica is extremely proud of her three children, Simon, Samantha and Tim, who have also dedicated their lives to Cornerstone and the treatment of addictive disorders. Like her husband, she is a doting grandmother of her five grandchildren.

Samantha Stone, BA

Executive Vice President

Samantha (likes to go by Sam) graduated from California State University, Fullerton with degrees in Psychology and Sociology. She has been with Cornerstone since its conception in 1984. She started in the Business office sending out insurance claims and collections. After that she moved to Admissions and Intake. She has spent most of her career in Intake/Admissions talking to potential patients and families about the programs at Cornerstone and what to expect. From Intake she moved into Management with becoming the Senior Vice President then President in 2019.

Personal Life:

Sam has love for all animals especially dogs and cats. She loves hiking, road-biking, movies, theater, traveling, and different cuisines.

Simon A. Stone, BA

Executive Vice President, Safety Officer, Corporate Business Development and Court Liason

Along side his duties as Senior Vice President of the company, Simon acts as Cornerstone’s Safety Officer. His main role addresses continuous quality improvement and management of Cornerstone estate. He ensures that the property is continuously well managed and that the facilities are up-to-date, comfortable and safe for our many clients, staff, and visitors.

Simon also assists in our Alternative Sentencing Program, where he passionately advocates for treatment in lieu of jail time in conjunction with criminal defence attorneys, public defenders, district attorneys, judges and commissioners.

Personal Life:

He enjoys surfing, traveling in his “sports mobile” and raising four beautiful children, four turtles, five fish, one dog, one cat, and one hamster, always with the constant support of his wife, Kari.

Timothy Stone, BA

Executive Vice President

Tim Stone has been part of the Cornerstone Team since 1999. He began his career assisting with the upkeep of the Recovery Residences that he now oversees. Tim’s responsibilities include ensuring that Cornerstone’s Recovery Residences are following the California DHCS, Joint Commission, and CCAPP regulations at all times. Tim is also responsible for Cornerstones IT, SEO, and overall online presence, working as the company liaison with our external expert partners in these areas. Tim is also responsible for our ‘Environment of Care’ team, which is accountable for all the on-going maintenance, repair, improvement, and housekeeping needs of the company.

Personal Life:

Tim enjoys surfing, reading a good book, and playing guitar. He was the Lead Singer/Songwriter for the music group The Goodkind (for those interested, find them on Spotify).

Tami K. Campbell, CADC-CAS

Executive Director

Regina Harris

Director of Operations

Aryan Monroe, MA, LMFT, CS

Clinical Director

Mark Ballard, CADAC I

Director of Admissions

Robert C. Griffin, SPHR

Human Resources

Roxanne Bates

Director of Clinical Outreach

Roxanne blends more than 33 years of recovery and personal growth together with over three decades of account management experience. Her unique insight into the needs of those seeking treatment developed when she began her career in behavioral health as an admissions manager and continued as she spent the last several years managing clinical outreach teams. For several decades, Roxanne has used her skills and passion to improve the lives of others on their journey to recovery. She has extensive experience working directly with individuals and their families to assure they receive the appropriate care necessary to experience the promises of recovery. An expert in crisis and family interventions, Roxanne enjoys a proven record for developing and maintaining relationships within the behavioral health community and has a reputation for always keeping patients and their recovery as her first priority.

Gabrielle Hilger

Operations and Clinical Support Services Manager

Lauren Agajanian

Alumni Program Coordinator

David Schornack, MA, AMFT

Assistant Clinical Director

Maria Carter, CADC II

Case Manager

Samuel David Michael, RADT

Outpatient Day Lead/Case Manager

Monnaye Bernal, MA, ACSW

Therapist

Taylor Tran, AMFT

Therapist

Mayra Melgoza, ACSW

Therapist

Diane Shaw, CADC II

Discharge Planner

Crystal Melms, CADC II, CCDS

Case Manager

Andy Kellems, CADC II

Case Manager

Lietta Brutsche, CADC II

Case Manager

Raul Perez, RADT

Case Manager

Erin Troske, SUDRC

Case Manager

Roberto Palacios, CADC I

Counselor Technician

Cory Weil, RADT

Counselor Tech

Marlys Wood, MS AMFT, MT BC

Music Therapist

Marlys Woods is a board-certified music therapist who has extensive experience supplying music therapy to substance abuse facilities. She has performed and taught music her entire life.

Marlys graduated from Chapman University in 2011 with a degree in music therapy and a minor in psychology, and she graduated from Vanguard University with an MS in clinical psychology. Marlys is in the process of becoming a marriage and family therapist and enjoys using her knowledge of relationships, people and music to help those who are struggling with addiction.

Marlys brings a variety of interventions such as active music making, songwriting, and lyric analysis, as well as relaxation techniques and art paired with music to her sessions. Marlys has successfully used these interventions to facilitate Cornerstone clients’ finding healthy coping skills as they move forward on their journey of sobriety.