Clinical Team


Cornerstone’s Clinical Team

Our adept and caring clinical staff are committed to melding traditional and innovative therapeutic methods, ensuring every individual’s personalized and thorough recovery journey. With a  variety of experiences and qualifications in addiction therapy, counseling, and mental health support, our clinical team enhances our multifaceted treatment approach, laying the groundwork for a transformative healing space. 

Dr. Stacey Smith PHD

Chief Clinical Officer

Stacey is a licensed psychologist in Arizona and Texas and has worked in the addiction field in residential and IOP settings since 2010. He has a wide variety of experience in addiction, including working with individuals who suffer from addictions to alcohol, drugs, intimacy/relationships, sex, and gaming addictions. Early in his career, Dr. Smith trained in EMDR techniques, knowing the critical role that trauma work plays in the recovery process. Most recently, an examination of how the brain works and how technology can play a crucial role in client recovery has been a focus of his work.

Dr. Yar Khan M.D.


Dr. Yar Khan earned his medical degree at the Medical University of the Americas in Nevis, West Indies. He completed his clinical training in the United States in Houma and New Orleans, Louisiana, and Chicago, Illinois. He then performed his internship and residency in internal medicine at the Mercy Hospital and Medical Center in Chicago, Illinois. Certified by the American Board of Internal Medicine, Dr. Yar Khan has special interests in outpatient primary care and hospitalist medicine including critical care. He has proficiency in endotracheal intubation, central venous catheterization, paracentesis, thoracentesis, lumbar puncture, and arthrocentesis. He’s also ACLS-certified.

Lionel Estrada, LASAC

Clinical Director

Lionel is a Licensed Independent Substance Abuse Counselor (LISAC) and has been with Cornerstone for over 4 years, beginning as a Primary Therapist then moving into the Clinical Director role. Lionel’s passion for helping people shattered by addiction has led him to become a fully trained EMDR therapist as well as a Certified Clinical Trauma Therapist. “Recognizing that drugs and alcohol are only part of the equation has opened my heart and mind to becoming trauma informed in my approach to helping our most broken fellow human beings.”

Rick Romero FNP, BSN, MSN

Director of Nursing

Rick received his BSN at Grand Canyon University in 2014 and his MSN at Georgetown University in 2018. He has seven years of professional experience providing care in a variety of settings ranging from persons with developmental disabilities, those suffering from serious mental illnesses, seniors, veterans, family practice, home health, and addiction medicine. He specializes in providing medical treatment to individuals across the lifespan and considers himself to be a medical “collaborator” first and foremost. As such, Rick focuses on incorporating every client’s experiences, strengths, values, and personal preferences into each individual plan of care.

Geraldine Rosa

Medical Assistant

Boasting a robust career spanning over two decades in health care including twelve transformative years in mental health and substance abuse, Geraldine brings an undeniable depth of experience and unwavering dedication to Cornerstone. Her fervor for guiding those ensnared by the clutches of addiction towards the path of recovery remains the core of her professional journey.

Angelic Schudt

Primary Therapist

Angelic has a Bachelor of Psychology from University of Las Vegas, Master of Social Work from Arizona State University, and is working towards a PhD in Performance Psychology at Grand Canyon University. Angelic has worked in mental health and substance abuse since 2012. Angelic most recently worked for Aurora Behavioral Health Care and Oasis Behavioral Health where she served dual diagnosed patients.

Nate Bush

Primary Therapist & Clinical Lead

Nate began his recovery journey May 5th of 2010. In January of 2013 he enrolled as a student at Central Arizona College later transferring to Arizona State University where he graduated with his Masters in Social Work with a focus in Adult Behavioral Health Direct Practice. He has been working in the Behavioral Health field since September of 2013. Today he is a Licensed Master Social Worker practicing as a Primary Therapist (and Clinical Lead). In addition to his personal recovery experience, among other things, Nate brings specialties in CBT, DBT, and the treatment of grief, as well as a personal passion for helping others to the family here at Cornerstone Healing Center.

Lori Pishke, MSAC, LASAC

Primary Therapist

Lori Mischke, MSAC, LASAC has been an active member of the recovery community since April 2013. Lori began her professional work in the substance abuse treatment field in 2016. Lori received her Bachelor of Science in Sociology from Grand Canyon University, where she graduated with honors, in December of 2016. Lori continued and received her Master of Science in Addiction Counseling from Grand Canyon University, graduating with honors, in February 2019. Lori’s therapeutic methodology includes, among other things, a combination of Motivational interviewing and Cognitive Behavior Therapy. Lori prides herself on her compassionate, empathetic, and well-rounded approach.

James Singler

Case Manager

James began his recovery journey on July 14th, 2020. Born and raised in Ventura, CA, he moved to Arizona seeking recovery and found community and support which allowed him to achieve long-term, lasting sobriety. Wanting to help others find the freedom from addiction that he found, James started his career in case management and is grateful to be able to help others create the life they have always wanted.

Still have questions about treatment?

Our admissions specialists are here to explain the process, answer any questions you may have, and ensure you’re getting the help you need to live a healthy life free from addiction.

Get Started

Call and speak with one of our caring team members about help for you or a loved one.