Meet Our Providers

Kimberly Mastis, MD
Medical Director
Board-Certified Adult, 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 over 15 years serving as medical director of Pediatric Behavioral Health and Neural Health Therapies.

Originally from New York, she has been a proud member of the greater Worcester community for the past 20+ 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.

Tracey Guertin, PhD, HSP
Clinical Director
Clinical Psychologist

Dr. Guertin is a psychologist with over 25 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

Licensed Mental Health Counselor

Kelly takes a holistic approach to therapy, emphasizing the connection between mental and physical health. Her work is primarily grounded in Cognitive Behavioral Therapy (CBT), while integrating elements of Dialectical Behavior Therapy (DBT), Motivational Interviewing, Interpersonal Therapy, and neuropsychotherapy based on each client’s needs. She has a particular interest in attachment and helping clients understand how early relationships and experiences can shape the ways they view themselves, connect with others, and navigate relationships in adulthood. Her approach emphasizes developing insight into these patterns while building practical skills to create meaningful and lasting change.