Our Providers

The Catalyst Health Team


Jerome (Jerry) Cohan, APRN

Chief Executive Officer

Nurse Cohan is an alumnus of East Tennessee State University College of Nursing. His clinical background includes experience in Neurology, Pain Management, and Addiction Medicine. He has a strong interest in fostering and maintaining community relationships to address polysubstance abuse and addictions.  His practice focus is on Methamphetamine and Benzodiazepine addictions as well as adolescent and young adult fentanyl abuse.

Timothy Smyth, MD

Chief Medical Officer & Medical Director

Dr. Smyth has served the residents and communities of Northeast Tennessee for nearly 20 years. He received his medical degree from the University of North Carolina, Chapel Hill School of Medicine and completed residency training at the University of Florida College of Medicine.

Dr. Smyth is an addiction medicine specialist, and has a background in addiction services, anesthesiology and pain management. He’s a diplomat of the American Board of Addiction Medicine and is the sitting President for the Tennessee Society of Addiction Medicine.

Michael Manning, MAH

Chief Operating Officer

Mr. Manning is an alumnus of East Tennessee State University Department of Allied Health Sciences. His administrative background includes direction of private practice, ambulatory surgery facilities, and healthcare consulting services.

He currently serves on the board of two local non-profit organizations. In addition, he is a committee member for surrounding anti-drug coalitions and prevention and education task forces.

Tina Cohan

Chief Financial Officer

Tina comes from a family of successful entrepreneurs in her hometown of Santa Barbara California and holds a degree in Business Management and Finance. She has called East Tennessee her home for 25 years. She has primarily served the local small business market through community center development, educational non-profit support, and outpatient mental health and substance abuse service programming. Her daily focus is creating pathways for individuals to access healthcare services through grant funding, charity care, and health coverage navigation.

She currently serves on the Board of Directors and Finance Committee for Ashley Academy and is an active member of the Tri-Cities MGMA Chapter.  

Zachary Hammons, MD

Director, Psychiatric & Behavioral Health Services

Dr. Hammons is a native of East Tennessee and received his medical degree from the Quillen College of Medicine. He completed his residency at the ETSU Department of Psychiatry. He is board certified through the American Board of Psychiatry and Neurology, as well as the American Board of Preventive Medicine.

Counseling Team

Andy Baker, LPC

Mr. Baker is a Veteran of the United States Navy. He is an alumnus of Middle Tennessee State University and completed his graduate work at East Tennessee State University. Mr. Baker pursued a career change in 2010 upon discovering his passion for counseling others undergoing addiction treatment.

Christen Moseley, LPC

Ms. Moseley is an alumnus of East Tennessee State University, receiving both her undergraduate and graduate degree. She is focused on helping her patients uncovering the best version of themselves through connecting with others and resources that support their recovery.

Steve Sherfey, MCJ

Steve is an alumnus of East Tennessee State University and Liberty University with degrees in Criminal Justice, Sociology, and Psychology. He is currently working on a Master’s Degree in Drug and Alcohol Counseling. Steve recently retired from the Johnson City Police Department as a Captain after 34 years in law enforcement. He also teaches Smart Recovery and the InsideOut program at various jails in the area. These programs assist inmates with addiction and prepare them for reentry into the community. 

Ashlynn Keasling, LMSW

Ashlynn is an alumnus of East Tennessee State University with a Master’s in Social Work and a Bachelor’s degree in both Social Work and Studio Art.  Ashlynn enjoys learning about mental health and believes psychoeducation is an important part of treatment.  Ashlynn’s primary therapy modality is Person Centered Therapy, however Ashlynn pulls from several other modalities as needed.  In her spare time Ashlynn enjoys long walks through craft aisles and plant nurseries, as well as spending time with her cats.

Jennifer Spry, BSW, CSAC

Jennifer is an alumnus of East Tennessee State University, where she received a Bachelors Degree in Social Work and is a Certified Substance Abuse Counselor recognized in Virginia. She is focused on assisting patients reach their best potential while meeting recovery milestones.

Megan Dew, LMSW

Meg is a Licensed Master in Social Worker. She has been in the field of Social Work for 7 years, with a focus on addiction work since 2018. Meg currently runs the Financial Assistance program, assessing clients financial needs to support affordable care. She brings a genuinely curious and empathetic approach to treatment, strongly desiring to meet clients where they are and help them build needed skills for self-development. Meg is flexible with adjusting treatment modalities to meet client needs, with a specific interest in Compassion Focused Therapy, Acceptance and Commitment Therapy, and Internal Family Systems.

Aubrey H.S. Roberts, MA, NCC

Aubrey, an alumna of University of Tennessee Knoxville and East Tennessee State University, finds passion in supporting and providing for others in their times of crisis, desperation, and journey to wellness. She believes that patients already have the power and ability within themselves to succeed; thus, the goal is to collaborate, explore the self, and meet healing. Aubrey believes that therapeutic work is to be guided by the patient. She emphasizes the control of choice and navigation each person has in their recovery; she strives to be consistently in your corner as you face challenges and growing pains. Together, through intervention specialized specifically to you, Aubrey hopes the relationship built and the resources provided will smoothly carry you into a life of recovery.

Greg Boykin, MSW, CPRS

Greg is an alumnus of the University of Pikeville, KY, and holds a Master’s degree in social work specializing in clinical mental health and substance use/opioid use disorders. He is also a certified peer recovery specialist who uses his life experience with addiction to support and empower others in their journey to recovery.

Lauren Graham, LMSW

Lauren is a Licensed Master Social Worker (LMSW) with 10+ years in the mental health and social work field. Throughout this time, she has worked with adolescents, adults, and families in a wide variety of settings. Lauren received a Bachelor’s Degree in Human Services and Counseling through Lindsey Wilson College before obtaining a Master of Social Work(MSW) from East Tennessee State University.
Recovering from addiction can be one of the most difficult roads in life for many individuals. Lauren is passionate about working with patients through a person-centered and strengths-based approach in order to further build upon the therapeutic relationship. Her goal is to establish a safe and supportive environment to assist patients through their journey of understanding past traumas, growth and healing, and developing new positive behaviors. Lauren also believes in treating the whole person in order to improve one’s quality of life. She places an emphasis on having one’s basic needs met and is very knowledgeable about community resources.

Clinical & Nursing Services

Charla Bacon, MSN, APRN, WHNP-BC, FNP-C

Nurse Bacon is a native of East Tennessee and an alumnus of East Tennessee State University. She is dually boarded in Women’s Health by the National Certification Corporation and in Family Health by the American Academy of Nurse Practitioners. She received her graduate nursing degree at the University of Cincinnati with a focus in Women’s Heath. Later she received a post-master’s in Family Health from King University.

Her clinical background include experience in pain management, primary care, and women’s health. She has dedicated her entire career to treating patients holistically, combining mind, body and soul.

Kimberly Lilley, MSN, APRN, FNP-C

Nurse Lilley is a native of East Tennessee. She recognized her passion for medicine while working as a Certified Nursing Assistant in a local skilled nursing facility. Kimberly worked her way through the ranks of nursing and then attained her Master of Science in Nursing in 2017. Kimberly completed her undergraduate and graduate degrees at East Tennessee State University.

Her clinical background includes acute care and primary care. She has dedicated her life to nursing and to serving the surrounding Tri- Cities communities. She feels every patient deserves to be treated with respect, kindness, and compassion.

Lauren Berry, MSN, APRN, FNP-C

Lauren is an alumnus of East Tennessee State University with her graduate degree in nursing as well as her undergrad in business administration. She is board certified in family health by the American Academy of Nurse Practitioners. Her clinical background includes experience in pain management and primary care. She is dedicated to helping her patients achieve their optimal health.

Meghan Hollier, PMH-NP, BSN

Meghan is an alumnus of East Tennessee State University where she received her graduate degree in nursing, specializing in psychiatry and mental health. She is certified through the American Nurses Credentialing Center. Her clinical background includes experience in emergency medicine and psychiatry.

Brianne Dunning, MSN/PMHNP-BC

Brianne is an alumnus of East Tennessee State University where she received her graduate degree in nursing, specializing in psychiatry and mental health. She is certified through the American Nurses Credentialing Center. Her clinical background includes substance abuse prevention and education.

Kathleen Seaton, MD

Dr. Seaton is a psychiatrist who specializes in addiction treatment and psychotherapy. She completed her medical degree at the University of Southern California, followed by a residency at Stanford University and a fellowship at the Medical College of Georgia. She is board certified through the American Board of Psychiatry and Neurology and the American Board of Preventive Medicine.

Martin Eason, MD

Dr. Eason received his medical degree from the University of Arizona and his specialty training in Anesthesiology and Pain Management from the University of Virginia.  He was formerly an associate professor at the Quillen College of Medicine at East Tennessee State University and an associate chief of staff at the James H. Quillen Veterans Affairs Healthcare facility in Johnson City.  While at VA, Dr. Eason chaired the committee to reduce the use of addictive medications among our veterans.  Dr. Eason also served as a fellow in Congress on the Committee for Veterans Affairs in the US House of Representatives. There, Dr. Eason assisted in the drafting of legislation to reduce the impact of illegal use of drugs in the US.   He has a strong passion to help those whose lives have been affected by addiction and has been involved in Addiction Medicine for approximately ten years, seven of which have been as an associate at Catalyst Health Solutions. 


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