“Mr. G” was born in 1950, is retired, married, and the father of a child. He and his family have described several hypomanic episodes each spring since 1996, with irritability, anger, and increase in the amount of speech, excessive, running thoughts, grandiosity and feeling fearless. Sodium valproate + valproic acid 1,000 mg/day was initiated in one of such episodes. Also, they have described depressive episodes occurring each winter since 1996. However, in 2003, Mr. G started to suffer from auditory and visual hallucinations. Meanwhile, the patient started to have sensory aphasia and difficulty in executive functions such as ordering, planning, and abstracting. The family informed us that the hypomanic and depressive episodes have disappeared since 2005. In his laboratory assessment, serum folate, vitamin B12, and thyroid hormone levels were in normal ranges, and HIV and syphilis markers were negative. Cranial MRI showed cerebellar and cerebral atrophy; PET scan revealed significant hypometabolism in bilateral parietotemporal regions. Neuropsychological assessment showed inability to maintain attention, frontal-type deterioration in verbal memory, impairment in visual-spatial configuration, language and speech apraxia, and difficulty in making and repeating sentences was noted. According to these findings frontotemporal-type dementia was diagnosed, and rivastigmine 16 mg/day was added by titration.