The term hyperventilation syndrome is a shortened version of the more descriptive “psychogenic hyperventilation syndrome,” which indicates a psychosomatic cause for breathing too deep and/or too fast. Basically, that means there is some sort of behavioral or emotional reason for the hyperventilation. In most cases, hyperventilation goes hand-in-hand with anxiety or panic disorders. Many of the symptoms of hyperventilation syndrome appear during what is commonly called a panic attack.
There are other, more serious medical conditions that may lead to hyperventilation. The most serious is related to an increase of pressure inside the skull (intracranial pressure), which can happen from a traumatic brain injury or from a stroke. The increased pressure pushes the brain through the foramen magnum, the opening in the base of the skull where the spinal cord exits. This is called herniation of the brain and leads to neurogenic hyperventilation syndrome, an involuntary reaction of the respiratory centers in the brain to increases in pressure.
For the purposes of this article, the term hyperventilation syndrome refers to conditions stemming from behavioral causes.