What psychological problems or issues do astronauts experience during spaceflight, that are caused by microgravity, background "white noise" or other unusual environments that astronauts in space are exposed to?
I am particularly interested in astronauts returning from long space missions (at least one month) onboard the ISS.
In order to study "cosmic illusions", a large-scale experiment was conducted by Institute of Biomedical Problems of the Russian Academy of Sciences, during which the pre- and post-flight state of cosmonauts' body was examined, and everything that happened was recorded on the ISS in microgravity. It turned out that in this unusual for the human body state [the microgravity], orientational, kinetic, coordinative and proprioceptive illusions are manifested.
Orientational illusions were observed in almost all cosmonauts (98%). They were expressed in the loss of perception of space. On the ISS, even after examaning the surrounding space, when the lights were turned off, sometimes there was complete disorientation - a person could not determine which direction and how long he should move to the target.
Kinetic illusion was characterized by [a false] sensation of rotation of one's own body around, as well as moving along an axis.
Some astronauts also noted an illusory sensation of the position of various parts of the body: “it seems that you are sitting bent, but actually you are lying flat in a sleeping bag”, “hands are at the top, but it seems they are at the bottom” - this is how proprioceptive illusions showed themselves.
Along with illusory reactions, 72% of astronauts had difficulty tracking a moving target and fixing their gaze on it, discoordinating manifestations were also noted - misses when trying to grab an object, hitting the head against a panel when “swimming” inside the station.
The article also describes scientific devices and methods used for their neurological study.
Results of the ANKETA and OPROSNIK experiments performed by 102 cosmonauts in and post flight were analysed. It is shown that perceptive disturbances (orientation illusions) developed in the period of early adaptation to weightlessness were not an inherent feature of individual persons but regular responses of the body sensory systems. The character, intensity, duration, and the dynamics of illusion responses in space mission are described. Forms of the vestibular disorders, types of adaptation of the sensory systems and classification of spontaneous illusion responses in the weightless environment are presented. Hypothesis for possible mechanisms of the illusion responses in weightlessness is suggested.
Unfortunately, the article is behind paywall
Further studies showed that the atmosphere was normal, and problems arose due to physical and psychological overload accompanied by the lack of physical excercise, poor sleep and poor psychological support from the Earth.
I was often still disoriented about how my body was positioned: I would wake up convinced that I was upside down, because in the dark and without gravity, my inner ear took a random guess as to how my body was positioned in the small space. When I turned on a light, I had a sort of visual illusion that the room was rotating rapidly as it reoriented itself around me, though I knew it was actually my brain readjusting in response to new sensory input.
Emphasis in all quotes mine.
The psychological effects experienced by the Apollo astronauts are well documented - check out Andy Chaikin's "A Man on the Moon" and Andrew Smith's "Moondust" for two great insights.
Chris Hadfield has also remarked that as well as physical reconditioning he's had to psychologically recondition, even to the simple acts of everyday living that were not present on orbit.
Generally speaking, astronauts are chosen based on psychological stability assessment results and trained to deal with the unusual circumstance of their job. I suspect that any significant long term negative psychological damage would be due more to the proclivity of the individual rather than it being spaceflight itself having a unique psychological effect. I suspect we just don't have enough long term data yet to say if space will make us crazy, but I wonder if there are perhaps studies done on other long term isolation scenarios such as saturation diving or remote outposts (e.g. Antarctica).
