Meet our Psychologists
Licensed. Expert neurodiversity-affirming evaluations. Here to give you answers.
Every evaluation at Grey Matter is conducted or directly supervised by a licensed
doctoral-level psychologist. We don't outsource interpretation.
Dr. Quincee Gideon
Quincee Gideon, PsyD
Licensed Psychologist | Founder & Owner
California License: PSY 29352
PsyD in Clinical Psychology | Certified Neurodiversity-Affirming Provider
Member, American Psychological Association (APA)
Dr. Gideon is the founder and owner of Grey Matter Psychological Assessment and the primary evaluating psychologist for ADHD, autism, and learning disorder assessments. She created Grey Matter to fill a gap she saw clearly: people who suspected they were neurodivergent struggling to access evaluations that were thorough, affirming, and actually useful in their real lives.
Her clinical focus is on comprehensive neurodiversity-affirming evaluations for children, adolescents, and adults — with particular expertise in ADHD across the lifespan, autism spectrum disorder in adults (including those who masked for years before seeking answers), and learning disorders such as dyslexia and executive functioning differences. She is a certified neurodiversity-affirming provider and brings that lens to every evaluation she conducts.
In addition to her assessment work, Dr. Gideon has received extensive training in forensic psychological evaluation — a background that informs the precision and rigor she applies to every report she writes. She is a member of the American Psychological Association (APA).
Dr. Gideon evaluates clients in person at Grey Matter's Santa Monica offices and virtually throughout California.
Specialties:
→ ADHD evaluation across the lifespan (children, teens, adults)
→ Autism spectrum disorder assessment, including late-identified adults
→ ADHD and autism in women and girls
→ Learning disorder testing (dyslexia, dyscalculia, dysgraphia)
→ Exam accommodations documentation (SAT, ACT, GRE, LSAT, MCAT, Bar Exam)
→ Neurodiversity-affirming assessment
→ Forensic psychological evaluation
Credentials at a Glance
• Degree: Doctor of Psychology (PsyD), Clinical Psychology
• California License: PSY 29352
• Certification: Certified Neurodiversity-Affirming Provider
• Membership: American Psychological Association (APA)
• Evaluation Ages: Children (6+), adolescents, adults
• Languages: English
• Telehealth: Available statewide in California
“A diagnosis isn’t a label — it’s a map. My job is to hand you that map in a
way that actually makes sense for your life, not just check a clinical box.
I started Grey Matter because I believe everyone deserves to understand
how their brain works, and to have that understanding treated as a strength.
”
Dr. Megan Johnson
Megan Johnson, PhD
Licensed Psychologist | Supervising Psychologist & Forensic Neuropsychologist
California License: PSY 31167
PhD in Clinical Psychology | Forensic Neuropsychologist
Member, American Psychological Association (APA)
Dr. Johnson is the supervising psychologist at Grey Matter Psychological Assessment, where she oversees the practice's clinical standards and brings deep expertise in both forensic and neuropsychological evaluation. She is the psychologist clients work with for complex cognitive assessments, neurological conditions, and evaluations connected to legal proceedings.
Her forensic training is extensive and field-tested. Dr. Johnson completed significant forensic work at Twin Towers Correctional Facility in downtown Los Angeles — the largest mental health facility of its kind in the world — where she evaluated individuals for competency to stand trial, criminal responsibility, and fitness for duty. That experience gave her rare, hands-on expertise in high-stakes psychological assessment under demanding clinical conditions.
Alongside her forensic background, Dr. Johnson specializes in neuropsychological evaluation — assessing and diagnosing conditions such as dementia, traumatic brain injury (TBI), and other cognitive impairments. She works with clients and their families to translate complex neurological findings into clear, actionable understanding, and to develop effective strategies for treatment and long-term management.
At Grey Matter, Dr. Johnson also conducts ADHD assessments, diagnostic evaluations, and mini-ADHD assessments, and plays a central role in maintaining the clinical excellence that defines every report the practice produces.
She approaches every evaluation — from a brief attention test to a full forensic workup — with the same empathy, rigor, and genuine commitment to helping clients find the answers they need.
Specialties:
→ Forensic psychological evaluation
→ Competency to stand trial evaluations
→ Criminal responsibility (insanity) evaluations
→ Fitness for duty evaluations
→ Neuropsychological assessment (dementia, TBI, cognitive impairment)
→ ADHD evaluation (mini and comprehensive)
→ Diagnostic testing
→ Conservatorship and capacity evaluations
Credentials at a Glance
• Degree: Doctor of Philosophy (PhD), Clinical Psychology
• California License: PSY 31167
• Training: Twin Towers Correctional Facility, Los Angeles (Forensic)
• Membership: American Psychological Association (APA)
• Evaluation Ages: Adults (18+)
• Telehealth: Available statewide in California
• In-person: Santa Monica, CA; concierge evaluations available in LA County
“Some of the most important work I do happens at the intersection of
psychology and the legal system — where a careful, honest evaluation can genuinely change someone’s life. Whether I’m assessing a TBI or conducting a forensic evaluation, I bring the same commitment: to see the whole person, not just the question I’ve been asked to answer.””
Every evaluation at Grey Matter is conducted by a licensed doctoral-level psychologist — not a technician, not an algorithm. We write every report ourselves, we deliver every feedback session personally, and we stand behind every conclusion we put on paper.
We are a small practice by design. That means you will always know who is evaluating you, you will always have direct access to your psychologist, and your report will never be a templated document with your name swapped in.
Our commitment to every client
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