Lithium: How Low Could We Go?

Background Notwithstanding its position as the gold standard mood stabiliser, lithium is under-used for several reasons including its adverse events when dosed within its known therapeutic window. Several strands of evidence are converging to establish lithium as neuroprotective, including preclinical and clinical neurobiological studies and trials of lithium for preventing or ameliorating cognitive impairments. These benefits may occur even at low doses. Aims & Objectives To examine the evidence base for using low dose lithium. Method Combining data from three studies, this presentation will discuss potential neuropsychiatric benefits that lithium may confer in low doses. Results Our findings indicate a protective association (particularly >80μg/L) between the quantity of trace lithium in publicly available drinking water and total suicide mortality (meta-analysis; subsequent data). Across studies of 300μg to ~200mg ionic lithium, a consistent effect emerges in attenuating cognitive decline, and more tentatively on depression and/or mania when adjunct to other therapies (systematic review). Studies unanimously reported safety. Safety was supported in our community survey of individuals who have taken commercially-available lithium supplements (~5 to 60mg per day) where wide-ranging subjective advantages were apparent, particularly in mood enhancement/stabilisation and cognition. Improvement was associated with longer durations of supplement use. Discussion & Conclusions Together, these data suggest that 'sub-therapeutic' lithium could have further benefits than have previously been supposed. There may be a trade-off between duration and quantity of lithium exposure in benefits. Commercially-available lithium has not been subjected to rigorous research and should be examined in long-term trials for people with subclinical cognitive or mood symptoms, and/or those at risk of neurodegenerative or affective illnesses.