OUR TEAM
Meet Our Team
Marcy Gunn, Psy.D.
Owner/Director of Child Psychology
Dr. Gunn is a licensed clinical psychologist who sees individuals of all ages. Having begun with a particular interest in working with children, adolescents and families, she now enjoys seeing clients across the lifespan. She has over thirty years of experience in the Dayton area providing therapy and assessments for a diverse range of needs, and she has been the owner of Cordell Associates, LLC for the past six years. Areas of expertise include treatment of childhood sexual abuse and other traumas; interventions with children who have experienced family disruptions such as divorce and/or foster or kinship care placement; assisting individuals on the autism spectrum and their families; and helping adult women cope through life’s transitions. Dr. Gunn also provides clinical supervision to several of the psychology residents and psychology assistants in the office.
Jonathan Cleveland, Ph.D.
Director of Adult Psychology
Dr. Cleveland (Jon) meets with adults who experienced difficult childhoods. Over the course of treatment, he collaborates with his clients to increase insight, self-esteem, resiliency, flexibility, the ability to trust, as well as the capacity for humor and creative expression. Jon specializes in treating trauma and dissociation using psychodynamic psychotherapy, hypnosis, havening, and EMDR (eye-movement desensitization and reprocessing). For clients wishing to focus on “parts work,” he incorporates ego state and IFS (internal family systems) techniques. He often meets with therapists who are seeking their own psychotherapy or professional consultation and enjoys supervising doctoral students and postdoctoral trainees.
Jon serves on the board of directors for the International Society for the Study of Trauma and Dissociation and is the current chair of membership for the Ohio Psychological Association. He is a clinical faculty member at WSU’s School of Professional Psychology, former editor-in-chief of Trauma Psychology News, and current editor of The Miami Valley Psychologist. In his leisure time, Jon finds himself cooking, reading, and tinkering with synthesizers. He also enjoys playing golf and traveling to new places to ski & scuba dive with friends.
Ray Oakes, M.A., LPCC-S
Clinical Supervisor
A Dayton resident since 1976, Ray has been affiliated with the practice since 1992. He has worked in partial hospital, intensive residential, outpatient and school settings with a primary focus on children, parenting & family. Consulting with school personnel to support achievement has been a major focus. Family, friends, exercise & social justice are passions that give purpose.
Erika Fontana, M.S.W., LISW-S
Clinical Supervisor
Erika earned her Master of social work degree from the University of Utah and has been a practicing therapist for over 16 years, with much of her focus on clients with trauma and substance abuse issues. She has received training in EMDR, havening, DBT, and seeking safety, and employs these and other treatment modalities including CBT and mindfulness training according to each client’s needs. She has experience working with adults, teens, children, groups, couples and families, and currently works with both adults and adolescents.
Areas of focus: Trauma, mood disorders, anxiety, grief and loss, substance abuse, relationship difficulties, communication skills, parenting skills
Stephen Hamilton, Ph.D. M.Div.,
Lt.Col. (ret)
Clinical Psychologist
Dr. Hamilton has been practicing with Cordell Associates since 2022. Prior to coming to the practice, he was a staff psychologist at Wright Patterson AFB mental health clinic and faculty member at their APA accredited psychology internship program. Originally from Southern California, he has a combined 32 years of clinical experience, both on active duty and following his retirement, as a civilian psychologist at the Dayton VA and WPat MH clinic. He has been trained in and practiced all the current evidence-based trauma treatments (CPT, PE, EMDR), but has found using the Havening techniques (a new and powerful therapeutic tool to help people recover from painful thoughts, memories, feelings and sensations) to be exceptionally effective. Dr. Hamilton is one of the first certified Havening practitioners and the only trainer in Ohio.
Given his career experiences, he likes working with military members and their families, veterans, first responders, performers, and athletes who seek to perform at a consistently high level under the most challenging conditions and succeed. His clinical interests are sports and performance psychology, anxiety disorders, behavioral health and positive psychology.
Kathryn Strieff, M.S.W., LISW-S
Independent Social Worker
Kathryn has experience and training in a variety of therapeutic approaches, including eye movement desensitization and reprocessing; dialectical behavior therapy; mindfulness; motivational interviewing; cognitive behavioral therapy; and problem solving therapy. To learn more about her philosophy and approach, you mayvisit www.KathrynLStreiff.com
Gregory Singfield, M.A., LMFT
Marriage and Family Therapist
Gregory earned his master’s degree in marriage & family therapy from St. Mary’s University of Minnesota. Prior to joining the Cordell team, Gregory, a relationship therapist, attained a variety of skills that have assisted him in working with couples, families, individuals, the Deaf/Hard of Hearing communities, and others who are working toward managing stress, drug/alcohol difficulties, conflict and personal growth journeys. Gregory is strongly committed to strength-based therapy and is passionate about assisting families in discovering and utilizing strengths while respecting their cultural values throughout the healing process. His specialties include families, couples, adolescents, seniors, emotional regulation, relationship difficulties, Deaf and Hard of Hearing, substance use disorders, parenting, and group therapy.
Linda DeRamus, Ph.D.
Psychology Resident
I love working in the field of psychology. Not yet licensed in the state of Ohio, I work at Cordell Associates as a psychology resident. It is a privilege to connect with people in their most honest and raw moments. I hold people’s pain with the utmost compassion and care. I hope the process of therapy helps you to increase your compassion for yourself. Sometimes therapy can imply that something is wrong and needs to be fixed. I prefer to think of therapy as a means to support one another in the path of life-long personal growth as we work together to resolve difficulties in the most enlightened ways possible.
Over the past 37 years, I have worked in a variety of settings, including inpatient psychiatric hospitals in Ohio and California, outpatient psychiatry in California and Kaiser Permanente, and in Hawaii as a director of mental health, overseeing mental health care of children, teens, young adults and families in Maui. At Cordell Associates, I focus on treating people who struggle with depression, anxiety, low self-esteem, trauma symptoms, eating and body image issues, relationship conflicts, difficulties with employers, obsessive compulsive disorder, and more serious difficulties. I look forward to connecting with you soon.
Kim Yost, B.A.
Pre-intake Specialist
Kim conducts pre-intake phone calls at Cordell Associates. He earned his bachelor’s degree in philosophy from Wright State University and is currently studying clinical mental health counseling at Liberty University. Kim enjoys cooking, cycling, gardening, and spending time with loved ones.
Jessica Hubbell, M.A.
Predoctoral Resident
Jessica Hubbell is a psychology resident in the final stage of completing her dissertation and doctorate in school psychology from Michigan State University. Jessica has extensive experience with assessment, creating and implementing behavioral plans, and consulting on system-level interventions. Jessica also has experience working in a state-run psychiatric hospital, consulting with psychiatrists, and providing outpatient psychotherapy to diverse patients.
Currently, she works with children, adults, and families. Jessica strives to create a comfortable, accepting, educational, and fun environment! Her preferred psychotherapeutic modalities are CBT, CPT, PCIT, and DBT. She is also being trained in EMDR and IFS. Jessica’s areas of focus are trauma (children and adults), social skills, parenting skills, relationship difficulties, communication skills, anxiety, depression, mood disorders, and parent/child relationships.
Aroosa Syed, Psy.M., M.S.
Psychology Assistant
Aroosa is a 5th year doctoral student at Wright State University’s School of Professional Psychology. Aroosa received her master’s degree in Clinical Psychology from Wright State University and her master’s degree in educational psychology from University at Albany. She received her bachelor’s degree in psychology from Buffalo State College. Her clinical interests include trauma, anxiety, depression, family/parenting, multicultural identity formation and assessment. She has been a trainee at Resilient Young Ladies and Gentlemen(RYLM), and Child Focus where she worked with young adults and provided individual and group therapy. Aroosa is skilled in cognitive, academic achievement, and personality assessments for both adults and children. Her research interests include emotion dysregulation in adolescents and different issues related to discrimination and racism. She typically takes a cognitive behavioral and feminist psychology approach to treatment. She has been enjoying working in private practice where she has been able to form meaningful connections and further develop her clinical abilities.
Vanessa Prosper, Psy.M.
Psychology Assistant
Vanessa is a 4th-year clinical psychology doctoral trainee at Wright State University’s School of Professional Psychology, where she received her master’s degree in clinical psychology and is pursuing a doctoral degree. She received her bachelor's degree in psychology from the University of South Florida with a minor in applied behavioral analysis. Her clinical interests include trauma, anxiety, depression, relationship concerns, mindfulness practice, assessment and racial trauma. Vanessa enjoys working with a wide variety of clients and diagnoses. She uses an integrative approach to treatment with a basis in client centered feminist theories. This allows her to center client's needs in treatment, address client's own capabilities to make changes, address systems that impact client's well-being and incorporate other evidence-based approaches towards
client's goals.
Elizabeth Thomsen, Psy.M.
Psychology Assistant
Liz is a third year Psychology Trainee at Wright State University’s School of Professional Psychology. Her professional interests include psychological assessment and psychotherapy with youths and adults. Her clinical interests include learning disorders, ADHD, academic struggles, anxiety, depression, and trauma. Liz works from a person-centered lens that incorporates a social-cognitive perspective and is passionate about helping people connect with their personal strengths and gaining trust in themselves.
Prior to pursuing her doctoral degree, Liz lived in Portland, Oregon where she earned her Bachelor of Science in psychology at Portland State University. She served her Pacific Northwest community through community mental health and crisis work, while also contributing to and leading research projects at the Center for ADHD Research at Oregon Health and Science University. Liz loves being outdoors and spending time with friends and family. She spends her free time skateboarding, swimming, camping, and hiking.