Psychology Internship Faculty

Brant VanOrman, PsyD, is the Training Director for the pre-doctoral psychology internship at Pine Rest. He graduated from Wheaton College after completing his internship with Pine Rest. He then conducted assessment and therapy at the Grand Haven clinic for two years before transferring in 2002 to the Psychological Consultation Center on Pine Rest’s main campus. He is an Adjunct Assistant Professor at Michigan State University’s College of Human Medicine.  His current outpatient work is largely related to psychological assessment and consultation. He was named Training Director for the internship beginning in 2007. He facilitates the integration of faith, science and practice through the Case Conference Seminar. He supervises the Child and Adolescent inpatient rotation.  

Scott Halstead, PhD, is a supervisor for the Van Andel inpatient rotation and neuropsychological testing. Dr. Halstead received his degree from Fuller Theological Seminary in 1992, served as a psychologist with the U.S. Air Force from 1991 to 2003, and completed a two-year neuropsychology fellowship at Brown University in 2000. Joining Pine Rest in 2003, he is the Corporate Director of Pine Rest’s Professional Practice Group.  He also provides outpatient and inpatient neuropsychological evaluations. Dr. Halstead specializes in working with older adults with memory disorders, and presents to interns on this and other assessment issues.

Ryan Jaarsma, PsyD, is the manager of Pine Rest's Southwest Clinic. He graduated with his doctorate from Wheaton College in 1998 after completing an internship at the Western Michigan University Counseling and Testing Center. He began working at Pine Rest in 1998, became an outpatient supervisor in 2001, Assistant Training Director in 2003 and Training Director in 2004. Dr. Jaarsma was instrumental in remodeling the internship program in 2004, proposing the inpatient / outpatient / outreach model and securing a grant to reach underserved populations. He is a member of APA and the American Association of Christian Counselors.  He continues to provide psychotherapy to adults, teens and children at the Pine Rest Southwest Clinic, where he serves as a supervisor.

Bruce Retterath, PhD, is a licensed psychologist who has practiced at Pine Rest Christian Mental Health Services since 1993. He is the manager of the Psychological Consultation Center at Pine Rest.  Dr. Retterath completed his undergraduate and doctoral degree at the University of North Dakota. His prior work experience includes inpatient, outpatient and residential settings. Dr. Retterath’s current clinical areas of interest include the assessment and treatment of ADHD, anxiety disorders and mood disorders, diagnostic/personality evaluations, pre-surgical evaluations, learning disability evaluations, and management consultations. Dr. Retterath is a member of the Anxiety Disorders Association of American, American Association of Christian Counselors, and Michigan Psychological Association.

Jen Sachek, PhD, is a licensed psychologist who has been at Pine Rest since October of 2007. Originally from Florida, Dr. Sachek completed her undergraduate degree at Florida State University.  She completed her doctoral degree in clinical psychology at Michigan State University, with an internship at the VA Northern California Health Care System.  Dr. Sachek currently works at the Psychological Consultation Center. Her clinical interests include ADHD, LD, personality, and mood/ anxiety disorder evaluations, as well as therapy with adults from an interpersonal/ relational perspective. She supervises the Center for Psychiatric Residential Services rotation.

Mark Steenwyk, PsyD, is a clinical Psychologist and intern site supervisor at Pine Rest’s Northeast Clinic. Dr. Steenwyk earned his bachelor’s degree from Calvin College and doctorate at Fuller Theological Seminary. Dr. Steenwyk specializes in treating depressive and anxiety disorders in children, adults, and adolescents primarily utilizing an ACT based treatment model. Dr. Steenwyk also developed and facilitates a post-hospitalization aftercare program, entitled the Healthy Living Group which is designed to provide support, education, and skills for individuals reintegrating into the community after an intensive hospital based treatment program. Dr. Steenwyk is a professional member of the APA and ACBS (Association for Contextual Behavioral Science).

Vitaliy Voytenko, PsyD, is a fully-licensed psychologist working at the Pine Rest Christian Counseling Center in Grand Rapids. A native of Ukraine, Dr. Voytenko completed his undergraduate studies at East Ukrainian National University. After moving to the United States, he received his doctorate in Clinical Psychology from Wheaton College (Illinois) and completed his internship at Massachusetts Mental Health Center, a Harvard Medical School teaching hospital. He also completed a formal post-doctoral fellowship in university mental health at Boston College. Much of Dr. Voytenko’s career has been in teaching and practical training of counselors and psychologists. He has published and presented on the topics of international/cross-cultural training and church-psychology collaboration. He has been a member of the Christian Association for Psychological Studies and the American Psychological Association.

Pamela White, PhD, is a fully licensed psychologist who has practiced at Pine Rest since 1994. She completed her undergraduate degree at Miami University and earned her doctorate in clinical psychology at Kent State University in 1987. She completed her internship at Ohio State University Hospitals and her post doctoral fellowship at a behavioral medicine/rehabilitation center affiliated with OSU hospitals. Prior to joining Pine Rest, Dr. White provided outpatient therapy and consultation at Children’s Hospital of Columbus, Ohio. She currently provides outpatient therapy and consultation to children, adolescents, and adults at Pine Rest’s Campus Clinic, where she serves as supervisor.

Timothy Zwart, EdD, serves as the supervisor for the Aspen inpatient rotation. Dr. Zwart graduated from Western Michigan University in 1988. At Pine Rest he administers the ADD Institute and provides assessments, consultation and therapy. Dr. Zwart provides psychoeducational presentations to parents on ADHD, stress management and parenting issues. He is member of the Michigan Psychological Association and American Association of Christian Counseling. Dr. Zwart also provides personality and career assessment training.

Executive Leadership

Mark Eastburg, PhD: President / Chief Executive Officer
Alan Armstrong, MD: Vice President/Chief Medical Officer
Bob Nykamp: Vice President / Chief Operating Officer
Scott Halstead, PhD: Corporate Director, Professional Practice Group
Susan Langeland: Corporate Director, Hospital Based Services
Al Jansen: Director, Residential Services
Gary Burkhart: Chair of Psychology Department


Tory Seif: Campus Clinic

Carol Rich: Northeast Clinic

Bob Bouws: Aspen Unit

Tiffany Idziak: CPRS

Becky Haas: Child and Adolescent Unit

Ric Lutke: Elm Unit



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