Sleep-related symptoms such as unusual dreams or insomnia did emerge during beta-blocker therapy for some patients. Beta blockers are medications that reduce the heart rate, the heart’s workload and the heart’s output of blood, which, together, lower blood pressure. They are a common treatment for cardiovascular diseases, including heart failure, arrhythmias, chest pains and high blood pressure. But despite being so commonly used, researchers have for long suspected that beta-blockers have negative psychological side effects, including depression, anxiety, drowsiness, insomnia, hallucinat...