Dr. Pia Quimson-Guevarra, DO

Dr. Quimson-Guevarra is a board-certified psychiatrist (DO) and founder of Quimson Behavioral Health, LLC, providing compassionate, culturally responsive mental health care for adults across Oregon and Washington. As a Filipina-American and BIPOC/AAPI provider, Dr. Quimson-Guevarra brings a thoughtful, individualized approach to psychiatric care, informed by her psychiatry training at Oregon Health & Science University (OHSU) and medical education at Western University of Health Sciences.

At Quimson Behavioral Health, care goes beyond brief medication check-ins. The practice is committed to providing deeply personalized, whole-person psychiatric care in an inclusive and affirming environment where every individual feels seen, heard, and respected. The clinical team combines evidence-based treatment with compassion, patient education, and counseling informed by psychotherapy frameworks including Cognitive Behavioral Therapy (CBT), Acceptance and Commitment Therapy (ACT), …and psychodynamic approaches.

The practice’s clinical services and areas of focus include:

• Culturally Responsive Psychiatry: Individualized, affirming care for adults of all backgrounds, including BIPOC, AAPI, and LGBTQ+ communities.
• Adult ADHD, Anxiety, and Mood Disorders: Comprehensive evaluation and medication management for ADHD, anxiety disorders, panic attacks, OCD, and major depressive disorder.
• Whole-Person Psychiatric Care: Thoughtful medication management integrated with patient education, therapeutic support, and collaborative treatment planning.
• Complex Adult Psychiatric Conditions: Comprehensive treatment for conditions including Bipolar Disorder, Schizoaffective Disorder, and Schizophrenia.

Dr. Quimson-Guevarra is joined by Cayley Mesterheide, PA-C, Psychiatric Physician Assistant, who provides psychiatric evaluation, medication management, and ongoing clinical care as part of the Quimson Behavioral Health team. Together, the clinical team strives to build collaborative, trusting relationships and create treatment plans that reflect each patient’s individual needs, goals, values, and lived experience.

Located in Bethany Village on the westside of Portland, Quimson Behavioral Health conveniently serves the Beaverton and Hillsboro communities while offering flexible virtual telehealth appointments throughout Oregon and Washington. The practice also provides dedicated monthly in-person clinic days for patients who prefer or benefit from in-person care.