about us

About Us

Acacia (“Ah-kay-sha”) Mental Wellness Centers is comprised of a comprehensive mental health management group that helps you flourish in life in a unique environment.We understand  that your mental health is more than just medication and brain chemistry. We believe your mood, thoughts, physical fitness, social connections, desires for purpose, and more all contribute to your mental health.

As a result, Acacia mental wellness studio offers comprehensive psychiatry, therapy, and holistic lifestyle services. Our dedicated care coordinators help guide you through our integrated, customized treatment process. We are committed to helping you flourish: Brain, Body, and Soul.

We are passionate about helping those with treatment-resistant depression. Our advanced treatment tools will help you feel better, faster: medication, innovative therapy, and transcranial magnetic stimulation.



David Carreon, M.D.

Psychiatrist, Medical Director

Dr. Carreon is a board-certified psychiatrist who received his psychiatric training at Stanford University.  He has been practicing since 2014, with a specialty in TMS and other neuromodulation techniques.  For the past five years, Dr. Carreon has conducted research at Stanford in the Etkin Neuroscience Lab, primarily focusing on the underlying physiology of psychiatric disorders, including MDD. Prior to practicing medicine, Dr. Carreon received a Bachelor of Science in Civil and Environmental Engineering at UCLA, with an interest in Global Health. Dr. Carreon is Acacia's Medical Director.

Nathan Meng, M.D.

Care Coordinator, Clinic Operations

Dr. Meng is a physician who trained at Stanford University. He most recently served as Chief Technical Officer of Ameda, Inc., a privately-held medical device company in the mother-baby space.  While at Stanford, Dr. Meng was also the Clinical Lead at Embrace, Inc., a start-up medical device company, also in the mother-baby space. Prior to medicine, Dr. Meng received a BS in Electrical Engineering and Computer Science at MIT and had an interest in medical devices. Dr. Meng runs Acacia's Clinic Operations and Finances.

Shauna King Hollis, PMHNP-BC

Nurse Practitioner, Acacia Partner

Shauna is a UCSF-trained psychiatric mental health nurse practitioner with over 20-years of experience in the field.  She specializes in ADHD, Anxiety, Depression, PTSD, Sleep Disorders, and Christian counseling.  Shauna provides personalized, compassionate, and holistic treatment plans that integrate medication management, therapy, health promotion, and spiritual well-being.  In addition, Shauna is a wife, mother, and retired veteran of the United States Navy.  She currently practices at Christian Counseling Centers in San Francisco.

Karen Yeh, Ed.M., Psy.D.

Clinical Psychologist, Acacia Partner

Karen is a clinical psychologist who specializes in anxiety, mood disorders, parent-child issues, couples therapy, relationship issues, adolescent & child therapy, stress & behavior issues, life changes, and spiritual/Christian counseling.  She received a Ed.M. in Counseling and Consulting Psychology at Harvard University and has trained in and practices specialized cognitive behavioral therapy called TEAM-CBT.  She is currently based at the Feeling Good Therapy and Training Center in Fremont.  Prior to therapy, Karen studied Biology at MIT.

M. Bret Schneider, M.D.

Psychiatrist, Advisor

Dr. Schneider is a board-certified psychiatrist with over 20 years of experience in the field.  He is one of the most experienced TMS specialists in the United States, using TMS to treat depression since 2003. He has operated his private TMS clinic in Menlo Park for over 10 years. Dr. Schneider also serves as Adjunct Professor of Psychiatry at the Stanford University School of Medicine, and has previously completed postdoctoral fellowships in Advanced Psychiatry and Stereotactic Radiosurgery, both at Stanford. Dr. Schneider’s title at Acacia is Consulting Attending Physician, and he will serve on the Clinical Advisory Board.

I love treating my patients with TMS because they usually get better and they usually get better fast.

I woke up and I just felt good. It was a weird sensation… I don’t feel this dark cloud over me.

47 year old woman, with bipolar depression after 6 sessions of TMS.

I’m thinking quicker. Thoughts take better directions. I don't have to fight as hard to think coherent thoughts, or be rational.

19 year old young man , with depression, after session 12.

The shoulders are lighter, the face is different. My cheeks are getting sore from smiling so much! ...This has enlightened my heart again.

60 year old woman , in remission by TMS after decades of depression.

I noticed I was appreciating things a lot more... noticing how nice it was on my walk to class.

21 year old university student , who got TMS for depression, which is now in remission.

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