Apeirophobia
Apeirophobia is a specific phobia, the excessive or irrational fear or phobia of infinity, eternity, endlessness, or the uncountable and is also known as the fear of infinity, the fear of eternity, or the fear of endlessness, causing discomfort and sometimes panic attacks from intrusive thoughts of the infinity. It normally starts in adolescence or earlier and it is currently not known how it normally develops over time. Apeirophobia may be caused by existential dread about eternal life or oblivion following death. Due to this, it is often connected with thanatophobia, chronophobia, nihilophobia, and other existential fears. Sufferers commonly report feelings of derealization which may cause the perception of a dreamlike or distorted reality. Existential OCD may sometimes be the cause of obsessive thoughts about infinity or eternity, which can lead to or trigger apeirophobia. Like other phobias, apeirophobia may be tied to mental health conditions such as anxiety disorders or obsessive-compulsive disorder. Martin Wiener, a neuroscience professor at George Mason University, hypothesized that apeirophobia is a manifestation of the fear of an unknown future, similarly to the fear of aging.
There is very little research on this phobia. Despite not being recognized specifically by the American [Psychiatric Association] in the DSM-5, it does meet their criteria for a specific phobia, which is a type of anxiety disorder. There are no known treatment methods that are specifically designed to treat apeirophobia, although some apeirophobes have benefited from anti-anxiety medications or cognitive behavioral therapy.