Psychic mediums channel the spirits of the dead, therefore they are also known as channellers in the US and UK. Spiritualism (communication with the spirit world) has its origins towards the end of the 19th century in the US and interest in it increased greatly after World War One with family members wanting to contact dead service men.
Mediums operate through Spiritualist churches where they talk to a large group of people and bring messages from the dead to people in the audience. Private sittings can also be arranged.
Bereavement is one of the main reasons people consult psychics and mediums can offer proof of life after death and reassurance about the continuing existence of the departed person. They can also pass on messages from the deceased. Psychic mediums have to be skilled in clairvoyance (receiving visual impressions), clairaudience (aural impressions such as voices) and clairsentience (feeling).
Sometimes spirits have physical manifestations such as ectoplasm (a white/silvery mist) or the facial features or voice of the medium changes. Physical manifestations of diseases or conditions within the body when that person died can occur, for instance the side of the medium's face collapses when channelling the spirit of someone who had a stroke, or developing a cough to represent a lung disease.
The medium may see someone carrying out a favourite occupation, or wearing a uniform perhaps to represent a soldier to give clues as to who the person is. For instance if a sailor is trying to contact his granddaughter, he may appear to the medium wearing a sailor's uniform and if he died drowning, the medium may experience difficulty breathing and may feel suffocated. Psychic mediums can also give guidance about people who are still living.
In Victorian times people used to hold séances in a darkened room where spirits communicated by knocking on the table. Physical phenomena occurred where spirits appeared as corporeal entities.
Another way the dead used to communicate with the living was through ouija boards: these are still in use now but have become less popular and are considered quite dangerous in amateur's hands as they can release spirits which cannot then be controlled. The board has letters and numbers in a semi-circle around the edge and the users rest their finger lightly on the pointer which moves from letter to letter to spell out words.
Automatic writing is another example of the dead communicating with the living - one medium plays piano compositions she believes are sent to her by the spirits of dead composers. Some authors believed that their works were being sent to them in this way. The messages can take the form of pictures rather than words.