Medical Director, Board Certified Psychiatrist

Dr. Martha R. Alzamora is a psychiatrist working with the adult population. She is the President and Medical Director of Nassau Psychiatric Services, P.C.

Dr. Alzamora completed her training in Adult Psychiatry at Mount Sinai School of Medicine. She worked as Assistant Professor at Mount Sinai School of Medicine, teaching, and training medical residents. Dr. Alzamora is a Diplomate of the American Board of Psychiatry and Neurology.

Treatment is available for Mental Health conditions, including but not limited to: Depression, Anxiety, Panic Attacks, Phobias, Post Traumatic Stress Disorder, Bipolar Disorder, Schizophrenia, Schizoaffective Disorder, Alcohol Abuse/Dependence. Dr. Alzamora offers support for people coping with domestic violence, family problems, physical illness, low self-esteem, and other life stressors.

Jennifer L. Eden  PMHNP-BC

Board Certified Psychiatric Nurse Practitioner

I am a board certified Psychiatric Nurse Practitioner.  I received my Bachelor’s of Arts in Psychology from the State University of New York at Buffalo and my Bachelor’s of Science in Nursing and Masters of Science in Nursing from Molloy College. After graduating from nursing school, I worked in the emergency department at Good Samaritan Hospital Medical Center in West Islip.

While working in the emergency department, I saw that people’s physical needs were being met, but their psychiatric needs were not.  This lit my passion to continue my education and pursue a psychiatric mental-health nurse practitioner certificate from Molloy College so that I could develop and implement patient-specific treatment plans that integrate medicine and mental health for the most complete and effective treatment. 

Before joining Nassau Psychiatric Services, P.C., I worked at one of the largest mental illness and chemical abuse (MICA) homeless shelters in Brooklyn. At the same time, I was part of an assertive community treatment (ACT) team providing care to those with significant functional impairment as well as serious and persistent mental illness or personality disorders, who have avoided or have not responded well to traditional outpatient mental health care and psychiatric rehabilitation services. My education, training, and professional experiences have prepared me to provide each patient with the utmost individualized care. I continue to have enthusiasm for learning, particularly cutting-edge science as well as knowledge involving the brain and body.

Gabriella Harrison, Psy.D.

Children and Family Clinical Psychologist

I am a New York State Licensed Clinical Psychologist since 1998. I have experience with adults, adolescents, children, families, and geriatrics. I treat a broad range of issues that include depression, anxiety, adjustment disorders, behavior disorders, ADHD, relationship issues, issues of self-esteem, trauma, and PTSD, sleep difficulties, adjustment to retirement, loss, and bereavement, and caregiver stress. I have worked with people affected by abuse and neglect, neurological disorders, obesity, and weight-related health issues, chronic pain, and stress-related health problems.

In therapy, I tailor treatment to the specific needs of each individual or family. I use cognitive-behavioral techniques, relaxation (breathing, muscle, and imagery), exposure therapy, behavior-management plans, mindfulness, and rational-emotive therapy.

When therapy is a safe place without judgment, and the treatment approach is personalized and supportive, people can enrich their lives with healthier attitudes and behaviors that empower them to create meaningful lifelong change.

Grisselle Virga, LCSW-R


I am a bilingual New York State Licensed social worker. I graduated with a Master's Degree in Social Work from Fordham University's Graduate School of Social Work in 2006. I have experience working with a wide range of mental health disorders some of which include Depression and Anxiety. My therapeutic techniques include cognitive behavioral therapy; solution focused therapy to help individuals who are suffering from mood disorders, relationship issues, recent stressful life experiences, health problems, and low self-esteem. 


Soy una Psicoterapeuta licenciada por el estado de Nueva York y proveo servicios en espanol que incluyen psicoterapia individual, terapia de pareja y de familia para aquellos que sufren de depresion, ansiedad, problemas matrimoniales, abuso domestico entre otros. Yo le ayudare a superar sus barreras y conseguir las metas que usted quiera lograr.


Me comprometo a brindarle respeto, apoyo, confianza, empatia, comprension y honestidad.  

George Isaac, M.D.

Board Certified Psychiatrist

I have a total of 45 years of experience as a fully qualified Psychiatrist and Child psychiatrist, out of which 14 years were in Public Psychiatry in New York State, encompassing the city, county, and state facilities. In addition, I worked several years in private, academic, and non-academic inpatient, outpatient, day treatment, consultation-liaison, Emergency Room, and Assisted Outpatient Treatment for children, adults, and the elderly in the United States, Canada, and India.

I have American Board Certification in Psychiatry since 1980 and in Child Psychiatry since 1986 as well as Canadian Board Certification in Psychiatry since 1973.

I was awarded the Nassau University Medical Center’s Dr. Julius Marcus Award for Excellence in Teaching in Psychiatry for the year 2007, and I have authored a few books, and several articles in Psychiatry in professional Journals. My writings on Bipolar Disorder in children span the past thirty years.



601 Franklin Ave, Suite 120

Garden City, NY, 11530

Phone: (516) 280-9030

Fax: (516) 280-9029

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2650 1st Ave S.

St. Petersburg, FL, 33712

Phone: (727) 800-9705

Fax: (727) 289-3053

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