
Adrien Mathieux, MA, is a Doctoral Psychology Intern at Forest Psychological Clinic who provides comprehensive psychological evaluations and therapy under the direct supervision of
Dr. James Thatcher, PsyD, Licensed Psychologist (Oregon PSY #3386).
Adrien works with children, teens, and adults seeking greater clarity about autism, ADHD, learning differences, intellectual functioning, emotional concerns, and other psychological or
neurodevelopmental conditions.
He brings a calm, gentle, and thoughtful presence to his work, helping clients and families feel comfortable discussing experiences that may be personal, complicated, or difficult to put into words.
His approach is strongly neurodiversity-affirming. Adrien is passionate about helping autistic and otherwise neurodivergent individuals better understand how they experience the world, recognize their strengths, identify meaningful supports, and feel more accepted as themselves. He listens carefully and takes time to understand each person’s history, communication style, challenges, strengths, and goals.
At Forest Psychological Clinic, Adrien participates in comprehensive psychological evaluations for children, teens, and adults throughout Lake Oswego, Portland, and the surrounding Portland metropolitan area.
Depending on the referral question, an evaluation may explore:
Autism spectrum disorder
ADHD and executive functioning
Learning disorders
Intellectual disability
Cognitive strengths and weaknesses
Anxiety, depression, and emotional regulation
Behavioral concerns
Personality and psychological functioning
Complex or overlapping diagnostic presentations
Adrien views psychological assessment as more than assigning a diagnosis. A meaningful evaluation should help people understand themselves more clearly, identify why certain areas of life may have been difficult, and find practical supports that reflect their actual needs.
For adults seeking an autism or ADHD evaluation, the process may provide language for experiences they have struggled to explain for years. Many adults have spent much of their lives adapting to expectations, concealing difficulties, or receiving diagnoses that captured only part of their experience. Adrien approaches these clients with curiosity, humility, and respect.
For children and teens, an evaluation can help families better understand learning, communication, emotional, behavioral, or developmental differences. The results may also clarify which supports could be helpful at home, at school, and in the community. As part of his advanced clinical training, Adrien may conduct clinical interviews, gather
developmental histories, administer and score psychological measures, work directly with clients and caregivers, contribute to diagnostic formulation, and assist with reports and feedback sessions.
Throughout the evaluation process, Adrien works under the direct supervision of Dr. Thatcher. Dr. Thatcher reviews the clinical findings, oversees diagnostic decisions, and provides professional review and sign-off on the final report.
This collaborative model allows clients and families to benefit from Adrien’s focused attention, curiosity, and developing assessment expertise while also receiving oversight from a licensed psychologist with extensive experience evaluating autism, ADHD, learning disorders, intellectual disabilities, and complex psychological presentations
In addition to psychological evaluations, Adrien maintains a small therapy caseload primarily serving teens, young adults, and adults. His therapy style is warm, collaborative, validating, and easy to engage with. Adrien works to create an environment where clients can speak honestly without feeling judged, rushed, or reduced to a diagnosis. He is especially attentive to clients who communicate differently, need additional time to process questions, or have previously felt misunderstood in therapy.
Adrien may support clients experiencing:
Autism or ADHD
Anxiety and persistent worry
Depression or low motivation
Emotional regulation difficulties
Anger, irritability, or explosive reactions
Obsessive-compulsive symptoms
School, college, or workplace stress
Social and relationship difficulties
Identity development
Neurodivergent burnout or overwhelm
His therapeutic work draws from Cognitive Behavioral Therapy, Dialectical Behavior Therapy, Acceptance and Commitment Therapy, and exposure-based interventions. Depending on the client’s needs, sessions may focus on recognizing patterns among thoughts, emotions, and behaviors, developing emotional regulation skills, increasing psychological flexibility, improving communication, or gradually approaching situations that have become associated with anxiety or avoidance.
Adrien does not assume that one therapeutic strategy will work for every person. He adapts treatment to each client’s communication preferences, developmental level, strengths, lived experiences, and goals. His aim is to provide practical support while helping clients feel understood, respected, and more confident navigating daily life.
Adrien has worked with autistic children, teens, adults, and families in clinical, educational, community, recreational, and research settings. These experiences have given him a deep appreciation for the many ways neurodivergence can influence communication, sensory experiences, emotional regulation, executive functioning, relationships, learning, and everyday life.
He does not approach therapy or assessment with the goal of making neurodivergent people appear more typical. Instead, he seeks to understand how each person experiences the world and which accommodations, strategies, environmental changes, or supports might make life more manageable and fulfilling.
Adrien is particularly thoughtful when working with autistic adults and individuals who may have gone unrecognized earlier in life. He understands that some people have spent years masking, compensating, or trying to meet expectations that did not account for their needs. He
works to create a space where clients can explore these experiences carefully and without judgment.
Adrien earned his Master of Arts in Applied Clinical Psychology from Pacific University and is completing his PhD in Clinical Psychology at Pacific University. His graduate research has included a systematic review examining Dialectical Behavior Therapy for autistic adults.
Before joining Forest Psychological Clinic, Adrien provided psychotherapy and psychological assessment through the Pacific Psychology and Comprehensive Health Clinic. He also received specialized clinical experience treating anxiety, obsessive-compulsive disorder, panic, trauma- related concerns, and depression through the NW Anxiety Institute.
Adrien has more than a decade of experience supporting autistic individuals and their families across mental health, educational, behavioral, recreational, and research settings.
He is fluent in English and French and can communicate with French-speaking clients and family members.
Outside of his clinical and academic work, Adrien enjoys traveling, learning about different places and cultures, and spending time outdoors. Having lived outside the United States, he values different perspectives and brings an open, curious, and culturally thoughtful approach to
his work.
Adrien is able to accept Kaiser Permanente, Moda Health, Regence and BlueCross BlueShield plans, PacificSource, and ComPsych.
Insurance participation and benefits may vary depending on the individual plan and service type. Clients and families are encouraged to contact Forest Psychological Clinic or their insurance provider to confirm coverage before scheduling an autism evaluation, ADHD evaluation, comprehensive psychological assessment, or therapy appointment.
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300 Oswego Pointe, Suite 220 Lake Oswego, OR 97034


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300 Oswego Pointe, Suite 220 Lake Oswego, OR 97034
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