madness

I think that the type of mould you describe only grows when fed with clean water. So any dampness on the wall will be from condensation and not from rising damp. rising damp is contaminated by salts. Lack of ventilation is a cause, as are drying clothes in the room and the fact that the walls are cold.

Clean the mould off with water and bleach as it appears and try to ventilate the room. You probably won't totally cure it but it should help to control it.