New-onset bipolar disorder in late life: A case of mistaken identity

A 60-year-old, right-handed, previously successful and psychiatrically healthy businessman was brought by his family to a university hospital neuropsychiatry service for consultation regarding behavioral and personality changes. When he was age 55 years, his customarily excellent financial and social judgment began to decline. Over the next 4 years, his attention to personal hygiene deteriorated, his business decisions became financially and ethically unsound, his range of social interests narrowed dramatically, and he developed an insatiable "sweet tooth." In the year preceding the consultation, his ability to maintain sleep diminished, he began spending money recklessly and impulsively and became unable to appreciate the feelings and concerns of others, and his speech and behavior took on a perseverative quality. Concurrently, he developed unprovoked, brief, frequent, and excessively intense episodes of tearfulness and laughing. These episodes lasted minutes at most, after which he would return to his usual euthymic emotional state. One month before the neuropsychiatric consultation, he had received a diagnosis of late-onset bipolar disorder and had begun treatment with lithium carbonate. When his serum lithium level reached the therapeutic range, his cognitive, behavioral, and motor function declined precipitously, prompting the consultation for a second diagnostic opinion. Is this patient's presentation consistent with late-onset bipolar disorder? What assessments are needed to clarify his diagnosis?.