Atypical presentation of frontotemporal dementia masquerading as bipolar disorder and substance abuse: a case report.

This is the case of a 44-year-old man with frontotemporal lobar dementia whose presentation was consistent with bipolar affective disorder with psychosis in addition to ongoing substance abuse. Despite extended periods of sobriety and multiple medications to target Bipolar Disorder, his symptoms remained refractory. With repeated brain imaging and progression of the disease, frontotemporal dementia was diagnosed. The patient went on to develop amyotrophic lateral sclerosis (ALS), which is known to overlap the neuropathological features with frontotemporal lobar dementia. Respiratory compromise ultimately led to this patient's death, which was deemed secondary to ALS. This case demonstrates the need for clinicians to recognize differential diagnoses in manic and psychotic symptoms resistant to polypharmacy.