Our Staff
![Eleftheria Tsavoussis, PMHCNS-BC](https://walthambehavioralhealth.org/wp-content/uploads/2015/01/Lefty2.jpg)
Eleftheria Tsavoussis, PMHCNS-BC
Owner, CEO & Psychiatric Clinical Nurse Specialist
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![Suzanne Brennan-Nathan, LICSW, C.G.P.](https://walthambehavioralhealth.org/wp-content/uploads/2015/01/Suzanne.jpg)
Suzanne Brennan-Nathan, LICSW, C.G.P.
Clinical Social Worker
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![Chris Shaw, PMHNP-BC](https://walthambehavioralhealth.org/wp-content/uploads/2015/01/Chris.jpg)
Chris Shaw, PMHNP-BC
Psychiatric Mental Health Nurse Practitioner
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![Christine Aposhian, Ed.D, M.Ed.](https://walthambehavioralhealth.org/wp-content/uploads/2015/01/Christine.jpeg)
Christine Aposhian, Ed.D, M.Ed.
Psychologist
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![Susan Korber, PMHCNS-BC](https://walthambehavioralhealth.org/wp-content/uploads/2018/11/Sue_Korber-e1543180404805.jpg)
Susan Korber, PMHCNS-BC
Psychiatric Mental Health Nurse Practitioner
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![Linda Simon LICSW](https://walthambehavioralhealth.org/wp-content/uploads/2018/11/Linda_Simon-e1543180326334.jpg)
Linda Simon LICSW
Clinical Social Worker
![Marylouise Demick, PMHNP-BC](https://walthambehavioralhealth.org/wp-content/uploads/2018/11/MaryLouise_Demick-e1543180161576.jpg)
Marylouise Demick, PMHNP-BC
Psychiatric Mental Health Nurse Practitioner
![Margaret (Meg) van Bael LICSW](https://walthambehavioralhealth.org/wp-content/uploads/2018/11/Meg_van_Bael-e1543180046333.jpg)
Margaret (Meg) van Bael LICSW
Clinical Social Worker
![Karen Kronenberg LICSW](https://walthambehavioralhealth.org/wp-content/uploads/2023/01/Karen-Kronenberg.jpg)
Karen Kronenberg LICSW
Licensed Independent Clinical Social Worker
Karen Kronenberg is a (LICSW) who specializes in helping adults who are facing issues with depression, anxiety, grief and loss, relationship problems or other mental-health concerns. Prior to joining Waltham Behavioral Health, she served as a hospice social worker, ran a dual-diagnosis group at a Partial Hospital Program, and as a psychotherapist at different mental-health agencies prior to WBH. Mental Health Association. Karen specializes in using a combination of psychodynamic therapy, cognitive-behavioral therapy (CBT), dialectical behavioral therapy (DBT), and Emotionally Focused Therapy (EFT) in a warm, supportive environment while challenging clients as appropriate. She holds a B.A. in Human Services from the University of Massachusetts/Boston and an MSW from Simmons University’s Graduate School of Social Work.