In 1926 the Association was granted a Royal Charter and became the Royal Medico-Psychological Association. The Association was also granted a coat of arms by the College of Arms. The Arms contains the serpents of Aesculapius and the butterflies of Psyche.
After the granting of the Charter and the Arms members established committees reflecting the specialist clinical fields of mental handicap (intellectual disability) and child and adolescent psychiatry, and a Social Psychiatry Section, renamed Psychotherapy and Social Psychiatry, in 1949.
It was during this period the Association chose its first female president, Dr Helen Boyle, in 1939.
Dr J. R. Lord, medical superintendent of Horton Hospital and president of the Association was involved in introducing malarial treatment for syphilis to England and developed the Malaria Laboratory at Horton Hospital.
The use of drugs such as antipsychotics and antidepressants, beginning in the 1950s, to alleviate some of the symptoms of mental illnesses, was a major development during the time of the RMPA.
In the 1960s, the Mental Handicap Section and the RMPA played a major role in drawing attention to the need for appropriate community services and in shaping national policy. The influence of the Section led to the founding of the International Association for the Scientific Study of Mental Deficiency in 1964. Members of the Section also played a prominent role and held office in the Mental Retardation Section of the World Psychiatric Association.
- 1937 – Indian Division established (dissolved in 1948).
- 1939 – Dr Helen Boyle is elected the first female president of the Association.
- 1960 – Dr Henry P Laughlin of the American Psychiatric Association (APA) attends the 120th Annual Meeting of the Association.
- 1962 – Dr Isabel Wilson becomes the 2nd female president of the Association.
- 1963 – The Journal of Mental Science becomes the British Journal of Psychiatry.
- 1964 – The founding of the International Association for the Scientific Study of Mental Deficiency – the first international association for scientific research on the specialty to be established.
- 1965 – The Blake Marsh Lectures launched in memory of Dr R. J. Blake Marsh, Medical Superintendent of Bromham Hospital, Bedford and first Secretary and subsequent Chairmen of the Mental Deficiency Section. The Lectures were funded by part of his legacy left to Association. The Lecture were to be on a subject related to mental deficiency.
- 1971 – The RMPA is granted a Supplemental Charter and becomes the Royal College of Psychiatrists.
- The Rules and Charters of the College and its predecessors, including the Royal Charter, from Madness to Mental Illness: A History of the Royal College of Psychiatrists (PDF)
- The records of the Faculty of Psychotherapy Psychiatry, dating back to the faculty's founding
- The records of the Faculty of Child and Adolescent Psychiatry