- Field-dependent relaxation effects in driven three-level atoms are studied at an arbitrary intensity and detuning of the field for all possible 3-level configurations. An analytical solution of the generalized master equations that incorporates the modification of the relaxation processes by the driving field is derived. Strong symmetry breaking is predicted between populations of the dressed levels. This is caused by field-dependent relaxation and leads to coherent population trapping of atoms in one of two Stark levels. It is shown that when a Stark sublevel crosses a former ground state, electromagnetically induced transparency and lasing without inversion may occur.