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Meet Our Providers

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Kimberly Mastis, MD

Medical Director

Board Certified Adult Psychiatrist

Board Certified Child and Adolescent Psychiatrist

Dr. Mastis has dual board certifications in adult and child & adolescent psychiatry. She graduated from Tufts University School of Medicine and completed her residency and fellowship training at

UMass Medical School in Worcester.

She has been in private practice for 10 years serving as medical director of Pediatric Behavioral Health. She remains an instructor of psychiatry at UMass Medical School. 

Originally from New York, she has been a proud member of the greater Worcester MA community for the past fifteen years.

She offers a personalized, strength-based, holistic approach in her work with patients and families, and is deeply rewarded by her ability to provide quality psychiatric clinical care within the community.

Dr. Mastis is a member of the

American Society of Ketamine Physicians and Clinical TMS Society. 


Tracey Guertin, PhD, HSP

Clinical Director

Clinical Psychologist

Dr. Guertin is a psychologist with over 20 years of experience providing clinical expertise in psychological assessment and cognitive behavioral therapy for multiple psychological disorders. She has extensive experience helping patients with biologically based medical and psychological disorders that include anxiety, depression, chronic pain, obsessive/compulsive behavior, and eating/weight problems.  She received her Ph.D. from Purdue University and completed post-doctoral training at Brown University and UMass Memorial Medical Center. 

Kelly Hobson, LMHC

Kelly Hobson, LMHC specializes in supporting pregnant and postpartum parents that are experiencing troublesome thoughts and emotions during the transition to parenthood.

Adrienne Sharpe
Office Manager
TMS Coordinator
Michael Birnkrant, LMHC

Michael is trained in talk therapy and analytic counseling, which focuses on resolving deeper issues, in order to improve and alleviate symptoms, improve interpersonal relationships, and gain better self-understanding.

He also teaches individuals CBT and DBT skills designed to rapidly alleviate unwanted symptoms that cause discomfort when they begin therapy. Michael has extensive experience working within various therapeutic environments with clients of all ages and diagnoses.

By creating a safe environment for expressing thoughts and feelings, Michael is able to help those who enter into a therapeutic alliance with him improve general satisfaction in interpersonal relationships and life.

Robyn Ernst, LMHC
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