MDMA can also cause problems with the cardiovascular system. This is because MDMA causes the body to release a hormone... moreMDMA can also cause problems with the cardiovascular system. This is because MDMA causes the body to release a hormone called serotonin, which helps to regulate blood pressure and heart rate. When serotonin is released, it can cause the blood vessels to constrict, which can lead to increased blood pressure and heart rate.