Solipsism syndrome refers to a psychological state in which a person feels that the world is not external to their mind. Periods of extended isolation may predispose people to this condition. In particular, the syndrome has been identified as a potential concern for individuals living in outer space for extended periods of time.
Overview
Individuals experiencing solipsism syndrome feel that the world is not 'real' in the sense of being external to their own minds. The syndrome is characterized by feelings of loneliness, detachment and indifference to the outside world. Solipsism syndrome is not currently recognized as a psychiatric disorder by the American Psychiatric Association, though it shares similarities with depersonalization disorder, which is recognized. Solipsism syndrome is distinct from solipsism, which is not a psychological state but rather a philosophical position, namely that nothing exists or can be known to exist outside of one's own mind; advocates of this philosophy do not necessarily suffer from solipsism syndrome, and sufferers do not necessarily subscribe to solipsism as a school of intellectual thought.
Periods of extended isolation may predispose people to solipsism syndrome. In particular, the syndrome has been identified as a potential challenge for astronauts and cosmonauts on long-term missions, and these concerns influence the design of artificial habitats.