Neuroprotective Effects of Low-dose Lithium in Individuals at Ultra-high Risk for Psychosis. A Longitudinal MRI/MRS Study

OBJECTIVES: To investigate if low-dose lithium may counteract the microstructural and metabolic brain changes proposed to occur in individuals at ultra-high risk (UHR) for psychosis. METHODS: Hippocampal T2 relaxation time (HT2RT) and proton magnetic resonance spectroscopy ((1)H-MRS) measurements were performed prior to initiation and following three months of treatment in 11 UHR patients receiving low-dose lithium and 10 UHR patients receiving treatment as usual (TAU). HT2RT and (1)H-MRS percentage change scores between scans were compared using repeated measures ANOVA and correlated with behavioural change scores. RESULTS: Low-dose lithium significantly reduced HT2RT compared to TAU (p=0.018). No significant group by time effects was seen for any brain metabolites as measured with (1)H-MRS, although myo-inositol, creatine, choline-containing compounds and NAA increased in the group receiving low-dose lithium and decreased or remained unchanged in subjects receiving TAU. CONCLUSIONS: This pilot study suggests that low-dose lithium may protect the microstructure of the hippocampus in UHR states as reflected by significantly decreasing HT2RT. Larger scale replication studies in UHR states using T2 relaxation time as a proxy for emerging brain pathology seem a feasible mean to test neuroprotective strategies such as low-dose lithium as potential treatments to delay or even prevent the progression to full-blown disorder.