Find a therapist in Great Neck, NY — covered by insurance

As a clinical psychologist, I assist patients in reshaping negative thought and behavior patterns in a judgement free setting.

Hi, I'm Jean-Jeffrey Marcellus, DNP, PMHNP-BC, AGNP-BC, a board-certified Psychiatric Mental Health Nurse Practitioner with over 19 years of healthcare experience. I provide compassionate, evidence-based care for adults experiencing ADHD, anxiety, depression, insomnia, and substance use disorders.

I specialize in Medication-Assisted Treatment (MAT) for alcohol, opioid, benzodiazepine, kratom, and prescription medication dependence. My approach is collaborative and personalized, focusing on creating treatment plans that support each individual's goals, recovery, and overall well-being.

I offer both in-person and telehealth appointments, providing a welcoming, judgment-free environment where patients feel heard, respected, and empowered. I am committed to delivering culturally responsive care and making high-quality mental health services accessible to individuals from diverse backgrounds.

Does your child or adolescent’s behavior leave you wondering, “What is going on?”Are they having meltdowns, withdrawing, struggling at school, worrying, or feeling sad? Children and adolescents often communicate their feelings through behavior long before they have the words to explain what they are experiencing.I work with children, adolescents, and families navigating challenges such as adoption, divorce, co-parenting, blended-family transitions, grief and loss, school-related worries, family conflict, and the growing push for independence. I help children and caregivers better understand what may be underneath the behavior while strengthening connection, communication, and emotional regulation. I am a Licensed Clinical Social Worker (LCSW) and Registered Play Therapist-Supervisor (RPT-S). I received my Doctorate in Clinical Social Work (DSW) and Master’s in Social Work (MSW) from New York University, and my Bachelor’s of Science in Social Work (BSW) from Cornell University. With more than two decades of clinical experience across inpatient, outpatient, and residential settings.

• I am a Daughter, Sister, Mother, & Ally.
• I was educated at the Hunter Bellevue School of Nursing in Manhattan, New York City, NY.
• My background is in Psychiatric & Correctional Healthcare.
• I offer Specialized ADHD/Autism 1:1 Weekly Coaching, Leucovorin & FRAT testing!
• Also, Medication Management, Talk Therapy, Goal Setting, Time Management, Fertility Support, Special Education Advocate, Weight Management, Confidential Religious Crisis Guidance.