Paper is devoted to the self-consistent analysis of thin current sheets (TCSs) formation in the presence of nonadiabatic effects. It is shown that nonadiabaticity of particle motion influences significantly the structure of young current sheets in which the particles have Speiser orbits. This results into the appearance of ions with large magnetic moments which reduces the current in the center of the sheet. The TCS then deteriorates, which leads to its aging due to the unavoidable nonadiabatic jumps of the adiabatic invariants of particle motion. When the resulting quasi-trapped domain becomes highly populated, the current decays. The characteristic lifetime of TCS due to the chaotic nature of the system is found to be about 10--60 minutes. This effect provides a new evolutionary mechanism which finally leads to the disruption of CS structure, at least in the frames of our 1D model.