Desey Tziortzis, Psy.D, Licensed Psychologist

Mountlake Terrace Location

Mountlake Terrace Location

Desey Tziortzis, Psy.D, Licensed Psychologist


I completed my master’s degree in Psychology (M.A.) and doctoral degree in Clinical Psychology (Psy.D.) at Pepperdine University in Los Angeles, CA. I am a licensed psychologist in Washington State, and I am also licensed as a psychologist in Oregon, New Mexico, and Arizona. I am a general practitioner, and I work with a wide range of diagnoses and issues, providing mental health services to individuals and families across the lifespan from all ethnic, cultural, and socioeconomic backgrounds. My areas of focus include individual psychotherapy with adults (18+) and family therapy. 


While in graduate school, I trained extensively in both inpatient and outpatient mental health settings providing intensive individual, family, and group psychotherapeutic services to children, adolescents, adults, and older adults. In addition, I’ve always had an interest in substance use disorders and addiction because of their relevance to society, their co-occurrence with other issues, and as common problems of contemporary life. I also enhanced my graduate training by working at UCLA on two NIH/NIDA funded research teams that conducted a variety of pharmaceutical/illicit drug related research studies. 

After earning my doctoral degree, I continued working in addiction research and was an adjunct faculty member at Argosy University in Orange, CA where I taught graduate level psychology courses. I then relocated to New Mexico to complete my postdoctoral training and began my work as a licensed psychologist at the New Mexico Behavioral Health Institute (NMBHI).

While at NMBHI, I acquired extensive inpatient experience including: crisis assessment and intakes/admissions, emergency and on-call services, individual and group therapy, milieu management, and providing court testimony for patients requiring continued psychiatric care. I then began working as a contract psychologist in the Pacific Northwest providing psychological services at facilities in need of providers. These clinical assignments further enabled me to advance and sharpen my skills within a forensic setting in the Seattle area, and a psychiatric hospital setting in Oregon State.  

After completing my contract psychology work in the beautiful Pacific Northwest, I decided to return to the great city of Seattle and establish my ongoing practice here.  


I provide brief and long-term psychotherapeutic services from multiple theoretical orientations including psychodynamic, existential-humanistic, cognitive, and behavioral frameworks. I blend elements from these approaches and tailor treatment according to each client's needs. The therapy is collaborative so that we can work together and find healthier, more adaptive ways to solve problems, decrease symptoms, and improve functioning and quality of life.

My training and work experiences have enabled me to provide psychological services to individuals presenting with a broad range of developmental and mental health problems including history of trauma, mood/affective disorders, substance use problems/addiction, anxiety, adjustment issues, dual diagnosis/co-occurring disorders, grief/loss, relational functioning, personality development, and severe/chronic mental health problems. 

As a licensed psychologist, I am dedicated to working with clients to foster personal growth, healing, and overall well-being. I aim to provide a safe and trusting environment, and to create a supportive, non-judgmental, and compassionate space to help make personally meaningful changes. I have a passion for my work and it’s an honor and a privilege to guide clients in their process of exploration, growth, and healing.