My daughter, now 40, was exactly the same at 18 months. She was an absolute nightmare, and rarely slept. We took her to see a paediatrician at Booth Hall Hospital, Manchester. He suggested it could be something in her diet, causing hyperactivity. After many tests, he prescribed a medicine called Vallergan Forte. The chemist refused to dispense it for such a young child. He said that one teaspoon would knock a horse out for 24 hours, and the doseage was 2 teaspoons, twice a day. He phoned the doctor for advice and was told to dispense it. It worked. We finally had some peace for the first time in months. Later tests showed that her hyperactivity was caused by an additive in orange juice called Tartrazine, E221, I think. Not sure about that number, but we kept her off orange juice and reduced the medicine doseage and in a matter of weeks, sge was just a normal, active child, sleeping soundly at night. That was our experience. It may not be the case for you, but worth a thought.