Fergal Keane talks to William and Kate Lyons about the devastating effects of bipolar disorder on both sufferer and carer. The lives of William and Kate Lyons, a young married couple, have included dealing with Kate's bipolar depression. It's a condition she has had most of her adult life and that William has to monitor constantly. It has led, on one occasion, to him having Kate sectioned under the Mental Health Act. They have decided to speak out because they believe there is a taboo surrounding the illness which can leave carers, as well as sufferers, isolated and vulnerable.