Practitioner Bios


Leon Smith, DO

Dr. Smith is the Medical Director of Eastside Outpatient Services (Muskegon, MI), Eastern Clinic (Grand Rapids, MI) and HTC Outpatient Services (Benton Harbor, MI).  Dr. Smith attended Wayne State University(Detroit, MI). He received a D.O. degree from the Philadelphia College of Osteopathic Medicine.

Dr. Smith enjoyed an illustrious career as a Family Medical Doctor which began in 1972 until his retirement in 1991. Throughout his career as the primary physician at his Family Medical Practice, Dr. Smith was an active medical staff member of Muskegon General Hospital. He was also an Associate of Family Practitioner and the American Osteopathic Association, in addition to continuing post-graduate CME training yearly as required by the state medical board. After working part-time in the field of addiction medicine, Dr. Smith was drawn to assisting people battling substance abuse and therefore he embarked on a full-time career in Addiction Medicine.

As a direct result of the Muskegon County Health Department, Dr. Smith founded the Eastside Substance Abuse Clinic in 1988 currently known as Eastside Outpatient Services. For many people battling their addiction to opiates; this clinic was viewed as a “last-result” in their recovery and Eastside Outpatient Services was also instrumental in the development of Eastern Clinic (Grand Rapids) and HTC Outpatient Services (Benton Harbor, MI) both of which are successful in battling substance abuse. Throughout the years the medical industry has changed and Dr. Smith has remained on top of the latest trends in science and technology. As Medical Director, he worked with the clerical, medical and clinical staff to develop a paperless addiction software system; currently used in all three clinics.

Dr. Smith found his true calling in the field of addiction medicine. He has been essential in patients seeing past the fog of substance abuse and entering into a lifetime filled with hope, happiness and dreams.


Kitty McCarthy, CNP

Kitty is a graduate of Grand Valley State College where she received her Bachelors of Science in Nursing degree.  She was chosen as 1 of only 10 students in the state of Michigan for specialized Nurse Practitioner program through University of Wisconsin and graduated this program in 1992. She has further specialized training as Women's Health Nurse Practitioner. She is licensed in the state of Michigan as a Nurse Practitioner.

Kitty has been a noted presenter at conferences involved in educating health care providers and the public about addiction and pregnancy and co-developed "Peer to Peer Neonatal Mother Support Program" at Helen Devos Children's Hospital. She has participated in Vermont Oxford Study which was aimed at decreasing Neonatal Abstinence Syndrome in the United States.

Kitty has served the community for over 25 years and has provided medical services in collaboration with Dr. Leon Smith at Eastside for over 8 years. She brings a passionate heart for providing support and care for any and all who struggle with the disease of addiction.



Mark Apman, BA, MA, CCS

Mark Apman was born and raised in California. In the 1980’s he received his Masters Degree in Clinical Psychology and later was licensed as a Marriage, Family and Child Counselor. He worked in private practice for a few years in the San Francisco Bay area and then moved his family to Muskegon. He became employed with West Michigan Therapy, a not for profit substance abuse clinic, and worked there for over 17 years in a variety of capacities. During that time he received his Certified Advanced Alcohol and Drug Counseling Certificate (CAADC) and also his Certified Clinical Supervisor Certificate (CSS-R). He is licensed in the State of Michigan as a Marriage and Family Therapist. A couple of his passions are playing handball and gardening.


Darien L. Smith, BA, MA

Darien is a graduate of Cornerstone University where he earned his Bachelors Degree in Business Administration. He is attended Western Michigan University, where he earned a Masters Degree in Counseling Psychology. He has over 16 years of experience within the realm of community service. Darien is devoted to building stronger communities, families and lasting relationships. He has spent the last ten years honing his skills within the substance abuse treatment and prevention arenas.

From the onset, Darien's vision for the clinic was to become interwoven within the healing and rebuilding process for the community and our society at large. With a strong belief in communities and a commitment towards helping others Darien leads his team to strive for a healing and rebuilding process; starting with one person at a time. With the above understanding Eastside Outpatient Services mission is: “To encompass individuals and their families; to help them beat the habit of using or abusing illicit drugs and to rebuild their lives one person and one family at a time.” In doing so, we will also build one unit and one community at a time together.


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