This technology includes GABAa a5 Negative Allosteric modulators (GABAa a5 NAMs) which have been recently discovered to act as fast-acting antidepressants in a variety of mouse models of depression. These NAMs are actively metabolized in vivo. This invention involves the conceptualization and synthesis of GABAa a5 NAM molecules with a deuterium in the active metabolic position. This significantly increased the metabolic stability, while still retaining the antidepressant activity.