Space psychology was a branch of psychology that studied the patterns which developed in the close quarters of a starship during long voyages in deep space.
Starfleet took the subject of space psychology quite seriously. For instance, the determination of the state of mind of a captain was important in court martial proceedings, and was facilitated by consultation with an expert in space psychology. (TOS: "Court Martial")
In 2369, several members of the USS Enterprise-D crew attended a three day conference on the psychological effects of long-term deep space assignments. (TNG: "Timescape")
Although the connection has not been established, this discipline was likely connected with exopsychology.