The stabilizing influence of diamagnetic drift effects on ideal and resistive interchange modes is investigated. A resistive-ballooning-mode equation derived from the gyro-kinetic equation is applied to a cylindrical model spheromak equilibrium. It is found that these kinetic effects can significantly improve the beta limits for collisionless interchange stability. For the resistive modes, the diamagnetic drift terms lead to growth rates which scale linearly with resistivity and are considerably reduced in magnitude. However, growth rates for near-term spheromaks remain significant.