Too many people may be damaging their health by self-medicating with sleeping pills, according to the Royal Pharmaceutical Society Thursday. It said half of people with insomnia diagnosed themselves and took medication without seeking medical advice. However, the society said insomnia was often part of other physical or mental health problems which needed treating. The warning was based on the findings of a survey of 2,077 people. Insomnia is difficulty in getting to sleep, staying asleep or getting enough good quality sleep night after night, doctors said. One in three people in the UK are thought to have bouts of insomnia. It can be caused by psychiatric problems such as depression, anxiety disorders and schizophrenia. Other illnesses including heart disease, Alzheimer\'s disease and hormonal problems can also disturb the normal pattern of sleep. In the survey, 30% of people said they had taken sleeping pills for more than a month without getting advice while 14% had gone six months.