One interpretation of Lilliput from a psychological perspective could focus on the disparity between Gulliver's size and the Lilliputians. Since Gulliver is enormous compared to the Lilliputians, he should be easily able to overpower and control them, but during his imprisonment and stay there he has little ability to control his own fate.
I perceived it to be a human creature not six inches high, with a bow and arrow in his hands, and a quiver at his back. In the mean time, I felt at least forty more of the same kind (as I conjectured) following the first. I was in the utmost astonishment, and roared so loud, that they all ran back in a fright... However, they soon returned...
(Swift, Gulliver's Travels, eNotes eText)
The Lilliputians tie him up, chain him, and use him as a weapon, and instead of destroying them or using his strength to cow them into fearing him, Gulliver meekly accepts them as his captors. This could be a metaphor for Gulliver's unease in society; he might feel that he is unable to act individually, and instead he is controlled by a thousand smaller forces that push him in various directions: his wife, his children, his societal responsibilities, etc. In this interpretation, Gulliver is unable to bring his full faculties to bear in dealing with others, and allows himself to be swayed by people instead of asserting his own personal opinions and rights.