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Photo of Dr. Mary C Johnston, MD

Mary C Johnston, MD

Assistant Professor of Psychiatry and Behavioral Sciences
Appointment Phone


Primary Location

The Johns Hopkins Hospital

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Out-of-State & International Patients +
Out of State Patients

Call 410-464-6641 (8a.m. to 6p.m., EST, Mon-Fri)

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International Patients

Call +1-410-502-0773 (7a.m. to 6p.m., EST, Mon-Fri)

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  • Assistant Professor of Psychiatry and Behavioral Sciences


Adult Psychiatry, Forensic Psychiatry, Geriatric Psychiatry, Memory Disorders, Psychiatry, Psychiatry and Behavioral Sciences

Research Interests

Outreach mental health care for homebound elders; Aging in Place; Memory Disorders


Dr. Johnston is is co-investigator of MIND at Home, a study measuring the effectiveness of pro-active care coordination to persons with memory disorders at home. In 2008, the American Association for Geriatric Psychiatry created the AAGP Deirdre Johnston Award for Excellence and Innovation in Geriatric Mental Health Outreach Services, to encourage programs providing mental health services to the frail elderly in their homes.
Dr Johnston''s previous appointment was at Wake Forest University School of Medicine, where she was the inaugural Director of the Kate Mills Snider Geriatric Psychiatry Outreach Program (the GO Program), an innovative model of collaborative in-home mental health care for the frail elderly. The GO Program and the Deirdre Johnston award were made possible by generous gifts from the Snider family of Salisbury NC and New York, in honor of their mother, Kate Mills Snider, in gratitude for Dr Johnstons care of Mrs. Snider.
Dr Johnston holds specialty qualifications in psychiatry in the UK and in Canada as well as in the United States and is certified by the American Board of Psychiatry and Neurology in both Geriatric Psychiatry and Forensic Psychiatry.


  • English

Additional Resources

Additional Resources +
  • Education +


    • University College Hospital ( Galway) (1979)


    • University of Alberta - Falculty of Medicine & Dentistry/Psychiatry ( EdmontonAlberta) (1989)
    • University College Hospital/Psychiatry ( Galway) (1985)


    • Geriatric Psychiatry, American Board of Psychiatry & Neurology (2005)
    • Psychiatry, American Board of Psychiatry & Neurology (1992)
  • Research & Publications +
  • Academic Affiliations & Courses +
  • Activities & Honors +
  • Videos & Media +
  • Upcoming Events +
  • Contact & Locations +


    The Johns Hopkins Hospital
    600 N. Wolfe Street
    Hospital Main Entrance - Sheikh Zayed Tower
    Baltimore, MD 21287
    Phone: 410-955-6158
    Appointment Phone: 410-955-6158
    Location Map


    • Psychiatry and Behavioral Sciences - Geriatric Psychiatry and Neuropsychiatry

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