The symptoms of mercury poisoning can vary depending on the type of mercury, the dose, and the duration of exposure. Acute exposure to high levels of mercury vapor can cause symptoms like cough, chest pain, and shortness of breath, along with neurological effects such as tremors and cognitive disturbances. Chronic exposure, particularly to methylmercury, can lead to more severe neurological and developmental damage, including cognitive deficits in children and motor dysfunctions in adults.