Mark GreenMark Green, MD

Addiction Psychiatrist and Founder

“It is such a relief to find a Doctor who actually listens to me, and understands exactly how I felt. For so long, I’ve felt frustrated, starting different medicines, feeling rushed in and out. It is wonderful to be making some real progress in my life at last.”

Mark graduated (UK version of) summa cum laude in neurobiology and then completed his medical degree at University College London. He knows an awful lot of medicine – general, sleep, pain, neurology and other areas. He came over to NYC for his Psychiatry residency then and Addictions fellowship (Payne Whitney Clinic, New York Presbyterian Hospital, Cornell Medical Center), and later conducted research in the neurobiology of addictions at Rockefeller University. He’s been on Faculty at Cornell (Asst. Prof), Vermont (Asst. Prof), and Harvard (Instructor) Medical Schools. He is dually boarded by the American Board of Psychiatry and Neurology in both general psychiatry and addictions.

Since graduating in 1999, Mark has set up & run addiction treatment programs (NYC, Vermont), directed supreme evidence-based dual disorders programs, overhauled national addictions and pain programs (Kaiser Permanente, Colorado) and treated thousands of patients.

Mark is an expert psychotherapist. He is trained in many modalities: psychoanalytic, cognitive behavioral, solution-focused, motivational, hypnosis, and others. He’s currently receiving training in Accelerated Experiential Dynamic Psychotherapy. Dr. Green’s therapy approach is relational, pragmatic, structured, direct, and emotionally vivid.

He is an expert psychopharmacologist, remaining cutting edge without taking undue risks with you, using what’s tried and tested, and imaginatively minimizing side effects. He often helps people get off med cocktails they’ve been stuck on for years. He sees medications as facilitating psychotherapeutic change.

He has written some articles in neurobiology, psychiatry and addictions, and lectured at major conferences nationwide.

Click here to read his resume.

Nicholas Barnes, MD


Nicholas Barnes MD is psychiatrist with a particular interest in treating patients with addictions, anxiety, depression, trauma and chronic pain. His psychotherapeutic approach utilizes psychodynamic techniques combined with mindfulness and self-compassion practices. He is currently on faculty at Harvard Medical School (clinical instructor in Psychiatry).  He graduated from residency at Cambridge Health Alliance / Harvard Medical School, received his MD from Dartmouth College and his BA from Hendrix College. In addition to working at Psych Garden, he also works at the Center for Mindfulness and Compassion at Cambridge Health Alliance, at the outpatient addictions service of Cambridge Health Alliance and in the Functional Restoration Pain program at Spaulding Rehab. He is affiliated with both Cambridge Health Alliance and MGH.

Drew Welch, RN

Nurse, Program Director, family therapist

“He’s the best nurse I ever worked with. We worked together for 6 years at WestBridge and I am really lucky he agreed to work with me at Psych Garden. He’s thorough, conscientious, caring, humble, courageous, honest and wicked smart.”

Drew Welch is a licensed registered nurse & therapist with over 20 years of experience working with individuals with co-occurring disorders as well as their families. He has extensive training in evidence based practices including motivational interviewing, cognitive behavioral therapies, family therapy, vocational rehabilitation and integrated dual disorders treatment and has super- vised and taught others these skills.

Drew was at WestBridge Community Services for 7 years as their nurse care manager, team leader and national wellness coordinator. Prior to that he was the Nurse Manager for the Co-occurring Disorders Unit at Bournewood Hospital.

Drew has more than 20 years of sobriety. He understands how impossible recovery can seem and that no single path works for all. He knows the importance of education, support and hope. These days he uses all his training, experience and passion to help others feel freer, prouder and more connected. Sometimes 12 step approaches help, sometimes CBT, sometimes a focus on exercise and diet (Drew recently completed his first triathlon). Side-by-side coaching can be invaluable to re- build the self-confidence withered by addictions and psychiatric illness; so he’ll do that too.

Stacey Peters, LICSW


Stacey received her Bachelor’s degree in Psychology from the University of Colorado at Boulder and her Master’s degree in Clinical Social Work (MSW) from Boston College School of Social Work. Stacey joins Psych Garden with 20 years of clinical experience working in a variety of addiction and mental health settings along the continuum of care (inpatient, acute residential, partial hospitalization/intensive outpatient, outpatient and telephonic).

Her experience includes working with individuals with co-occurring disorders ranging from adolescence to seniors and their loved ones or employers via employee assistance consultation services. She worked many years in Emerson Hospital’s Addiction Rehabilitation Program and coordinated the Evening Intensive Outpatient Program prior to transitioning to an outpatient community mental health setting in most recent years.

Stacey has a warm, interactive and relational style and draws from a variety of modalities: cognitive-behavioral, solution-focused, motivational, mindfulness, 12-step and SMART Recovery. She’s committed to providing well-informed, respectful and compassionate care using a holistic perspective and strong belief that each individual can discover their individualized path to personal recovery.

Karen MacKenzie, LICSW

Individual and Family Therapist

Karen is a compassionate, focused and experienced therapist who has special expertise in working with couples and families, including those affected by addictions.

Her training includes Emotionally Focused Therapy, a short-term model proven effective in healing relationships, as well as psychotherapy from relational, systemic and CBT models and community Reinforcement Approach. In addictions work, she has learned from both 12-step and Harm Reduction perspectives and individualizes care.

She uses an experiential and systemic approach to assist clients in identifying patterns of feelings, thoughts and behaviors that occur in times of stress, and to change them so as to achieve success, happiness and intimacy. Karen believes that by collaboratively recognizing, honoring, and building on the strengths and resources clients possess as well as the impact of close relationships, they are able to glean a sense of hope and agency for the future.

Karen was a registered nurse before changing careers, studying psychology (summa cum laude) and then obtaining her masters in social work at Simmons.

Francis Guerriero, LICSW


Francis is a deep therapist who brings a wealth of experience with DBT and mindfulness practice to us. Francis trained and practiced at McLean Hospital for seven years, working at the OCD Institute and 3East. He has extensive experience with mindfulness-based therapies, is certified in Dialectical Behavioral Therapy, has taught Mindfulness to therapists at the graduate level and brings 25 years of personal experience with contemplative Eastern and Western spirituality and tradition. His Bachelors was in Human Services with a focus in holistic psychotherapy from Lesley University, and Master’s degrees in both Social Work and Theology and Ministry from Boston College. He is a graduate of the Institute for Existential-psychoanalytic Therapy and a steering committee member of the New England Center for Existential Therapy.  Francis enjoys engaging at the threshold where psychotherapy and spirituality meet, welcoming religious and spiritual issues into the therapeutic work. His current specialty is in the treatment of trauma and addiction, including the Internal Family Systems model and the integration of non-ordinary states of consciousness; including being one of the few trained therapists that use psychedelic experiences in treatment, as part of the very important national FDA-approved trial of MDMA-assisted psychotherapy for PTSD.

Jennie Knott, LICSW


Jennie received her MSW from Simmons College in 2013, and a post-masters certification in the multi-contextual treatment of trauma in 2015. She is trained in Internal Family Systems (IFS) therapy and is a passionate practitioner of integrative harm reduction psychotherapy. Jennie has worked with: REACH-Beyond Domestic Violence, the Cambridge Health Alliance, the AIDS Action Committee of MA, and Massachusetts College of Art. Such diverse experience reflects Jennie’s commitment to giving the best possible care to those often given short shrift. She is smart and precise, but is warm and welcoming.

Danielle Green, LICSW

Couples and Family Supervisor

Danielle is Founder of the New England Center for Couples and Therapy, in Arlington. She received her MSW from Columbia University in 1993 and completed 5 years of further specialist training in couples and family therapy at the Ackerman Institute for the Family, in New York City. She worked and taught at Cornell Medical Center for 10 years before relocating to Boston to serve as Clinical and Training Director of the Couple and Family Therapy Program, at the Cambridge Health Alliance, Harvard Medical School. There, she trained psychologists, psychiatry residents and social workers and lectured extensively throughout the Harvard system. Danielle is a certified EFT (Emotionally Focused Therapy) therapist and supervisor. Danielle helps couples develop skills to restore trust, communicate and express feelings effectively, understand and resolve differences, and enhance intimacy. It is Danielle’s passion to help couples repair their connections and create secure and lasting bonds with those who matter the most. Danielle also offers supervision to advanced practitioners.

Kerri KuklentzKerri Kuklentz, MS CRC CPRP, NASM-CPT

Case Manager/ Fitness Coach/ Rehabilitation Specialist

Kerri has more than 10 years experience as a case manager for persons with mental health challenges and addictions. We worked together for many and she was incredibly warm, supportive, inspirational and effective, helping people identify core values, get back to accomplishing, living fully through work, education, social connection and healthy living. Then she left to be a personal trainer and a mom for several years and now we are lucky to work with her again, with these added skills and perspectives. She believes exercise is a key path to building self-esteem, gaining acceptance with one’s body and feelings, and attaining balance in life.

Camillia JoyCamillia Joy

Office Manager

Camillia is the office manager for our practice. She grew up in Idaho with a love for dance, soccer and skiing. After graduating from The Thacher School in Ojai, CA she moved to Portland, OR where she spent 15 years enjoying the city’s eclectic culture and local music scene. In 2008 she and her husband relocated to the Boston area to be closer to family as they started a family of their own. Aside from spending time with her daughter, Camillia enjoys being an active member in the community and manages a large listserv for families in her town. Her compassion and warm personality are a perfect fit with our providers and the desire to make every client at Psych Garden feel welcome.



Miles received his initial training on a farm in rural OK before an internship in Belmont and further training at the Psych Garden. We are honored that he has chosen to continue his studies with us and contribute his warmth, gentleness and insights. He is a hypoallergenic poodle-cavalier mix. Like our other staff, he doesn’t bark or bite.