A 55-year-old male with semantic variant-primary progressive aphasia was evaluated for outbursts of severe agitation, skin picking, frequent elopement attempts, and multiple instances of shoplifting. At the time of evaluation, he was being treated by another psychiatrist with donepezil 23 mg, clonazepam 1 mg, duloxetine 60 mg, fluvoxamine 100 mg, venlafaxine 37.5 mg, lisdexamfetamine 30 mg, and lithium 600 mg daily. When behavioral symptoms did not fully resolve, lithium was increased to 1200 mg daily, which was reduced to 600 mg after one week when he became sedated and developed a tremor. The initial improvement in behavioral symptoms was maintained and all other psychiatric medications were tapered and discontinued over time. The patient remained on lithium until his death two years after starting treatment. Serum lithium levels were not recorded.