Our Staff
Eleftheria Tsavoussis, PMHCNS-BC
Owner, CEO & Psychiatric Clinical Nurse Specialist
Eleftheria Tsavoussis is a seasoned Psychiatric Clinical Nurse Specialist and Adult Nurse Practitioner with over 25 years of experience across multiple healthcare settings. She offers psychopharmacologic treatment for adult clients with a focus on resistant depression, anxiety and panic disorders, ADHD testing and treatment, bipolar disorder, substance abuse and women’s issues.Click here to learn more
Suzanne Brennan-Nathan, LICSW, C.G.P.
Clinical Social Worker
Suzanne Brennan-Nathan’s areas of specialty include: trauma, sexual abuse, depression, group psychotherapy, eating disorders and adult children of alcoholics and dysfunctional families. She has over 30 years of experience in counseling and social work.Click here to learn more
Chris Shaw, PMHNP-BC
Psychiatric Mental Health Nurse Practitioner
Christopher Shaw offers psychopharmacology services for adolescent and adult patients. He specializes in treating patients with dual diagnoses of mental health and addictions. In addition to his work with Waltham Behavioral Health, LLC, Mr. Shaw is a nurse practitioner Addictions Consult Team Leader at Massachusetts General Hospital.Click here to learn more
Christine Aposhian, Ed.D, M.Ed.
Psychologist
Christine Aposhian has over 30 years of experience in the mental health field with a special interest in diagnosing and treating bipolar spectrum disorders. She especially enjoys incorporating the arts into therapy. Prior to joining Waltham Behavioral Health, Ms. Aposhian was a psychologist at Greater Lowell Psychiatric Associates, at The Psychological Center in Lawrence, and the North Essex Mental Health Center.Click here to learn more
Susan Korber, PMHCNS-BC
Psychiatric Mental Health Nurse Practitioner
Susan Korber, PMHCNS-BC Sue Korber is an experienced clinical nurse specialist treating children, adolescents and adults across the lifespan. She offers psychopharmacologic assessment and treatment for these patient populations and has been working in this arena for thirty-one years. She has extensive experience working with affective disorders such as Depression and Bipolar disorder, ADHD, PTSD, Autism Spectrum Disorders, Disruptive Mood Dysregulation disorder, Substance Use disorders and has special expertise in Tourette’s Syndrome and other movement disorders.Click here to learn more
Linda Simon LICSW
Clinical Social Worker
Linda Simon LICSW Linda has more than thirty years’ experience treating children, adolescents and adults in individual, couples and family therapy. She focuses on the needs of each client through the integration of cognitive-behavioral therapy (CBT), psychodynamic psychotherapy and family systems modalities.
Marylouise Demick, PMHNP-BC
Psychiatric Mental Health Nurse Practitioner
Marylouise Demick, PMHNP-BC, has psychiatric experience providing psychotherapy and psychopharmacology treating patients in both inpatient, partial programs and adult outpatient clinical settings. She is currently a Psychiatric Nurse Practitioner at McLean Hospital and serves as adjunct faculty at Boston College. While working as a staff nurse at Brigham and Women’s Hospital, Marylouise’s primary interests were parenting education and family intervention in areas of perinatal loss, In Vitro Fertilization, postpartum depression and parenting. Before working at Waltham Behavioral Health, Marylouise continued building her expertise by completing a postgraduate psychiatric residency at the Boston VA concentrating on depression, anxiety, mood disorders, trauma, addictions, PTSD and narrative therapy.
Margaret (Meg) van Bael LICSW
Clinical Social Worker
Margaret (Meg) van Bael has worked in the mental health field for thirty years with adults of all ages. Her areas of specialization include unipolar and bipolar depression, PTSD and other anxiety disorders, adult children of alcoholics, dual diagnosis (substance use disorder and mental illness), chronic illness and stress, life role transitions and issues of grief and loss. Since she believes that there is no such thing as “One size fits all” when it comes to mental health treatment, her style is eclectic, incorporating supportive interpersonal work, CBT, mindfulness and other modalities. During her academic training, she worked at the EN Rogers Memorial Veterans’ Hospital before graduating Summa cum Laude from the Salem State Graduate School of Social Work. Prior to joining Waltham Behavioral Health, she worked for McLean Hospital, Program of All-inclusive Care for the Elderly (PACE) and Jewish Family and Children’s Service. She is a member of the Private Practice Shared Interest Group of the Massachusetts National Association of Social Workers.
Mary Woodland LICSW
Clinical Social Worker
Mary Woodland is an independently licensed clinical social worker who has extensive experience working with children, adolescents and young adults in a variety of levels of care, including community-based services, short term acute residential and long term residential care settings. In her career, she has completed individual, family and group therapy in addition to on-call crisis support. Mary also works as a clinical social worker at Boston Children’s Hospital. In this role she supports children and adolescents struggling with a variety of behavioral health difficulties, working collaboratively with these patients and their families in providing intensive short-term individual intervention and regular family therapy.
Charlotte Baillieul, PMHNP-BC, LICSW
Psychiatric Mental Health Nurse Practitioner
Charlotte Baillieul, PMHNP-BC, LICSW is a psychiatric nurse practitioner and licensed independent clinical social worker who has worked in mental health settings with children, teenagers and young adults for the past decade. With experience in academic, outpatient and residential settings, she offers on-going psychopharmacological assessment and treatment as well as education and support to patients and families, with a particular focus on helping understand the developmental and social needs throughout treatment. She has extensive experience working with young people, young adults and their families in the areas of anxiety, mood, and adjustment disorders, ADHD, and other behavioral health disorders.
Martine Rossell LMHC, ATR-BC
Licensed Mental Health Counselor
Martine Rossell is a Licensed Mental Health counselor, School Adjustment Counselor, and Board Certified Art therapist. Martine got her Master’s in Mental Health Counseling with a specialty in Art Therapy from Lesley University in 2015. She interned at the Franciscan Hospital for Children and has worked as a school counselor and Expressive therapist in residential and school settings. Martine works primarily with children, adolescents, and young adults. Martine brings with her extensive experience working in special education with individuals diagnosed with intellectual disabilities and/or developmental disorders. Martine has also worked with individuals who have experienced trauma using DBT, CBT, and knowledge of how art can be used with these and other approaches to facilitate psychological growth and healing.
