Most people believe that older adults with memory loss are more likely to develop dementia, and are therefore wary of memory loss and often advise patients to seek medical attention as soon as possible. It is true that some common types of dementia, such as Alzheimer’s disease (dementia), have memory loss as the first symptom and main manifestation, but this is not always the case. Some types of dementia are characterized by early manifestations of mental-behavioral abnormalities. These abnormalities are usually more insidious and can easily be mistaken for signs of aging in the early stages and are not actively sought after, resulting in delays in diagnosis and treatment. The following mental, personality, and behavioral changes should be taken seriously when older adults appear, such as becoming fragile, unkempt, childlike and childish, and unashamed. FTD can be the first manifestation of many diseases, but frontotemporal dementia (FTD) is the most common among the elderly and is currently considered to be the second most common neurodegenerative disease after Alzheimer’s disease (dementia) in terms of incidence. FTD has an insidious onset, and the earliest and most prominent aura symptoms are mainly emotional changes, such as depression, anxiety, and excessive sentimentality, which are easily overlooked. As the disease progresses, patients develop complex personality changes and social behavior decline, such as indifference, selfishness, aggressiveness, no longer modest, polite behavior decreases, and personality disorders are more prominent, such as neglect of personal hygiene, open defecation, lack of attention to instrumentation, and even naked strolling. Some patients change their eating patterns, eat excessively and uncontrollably, prefer sweets, and put inedible things into their mouths to taste them, such as swallowing soap. There is a gradual loss of flexibility and rigidity in daily life, such as overly strict punctuality, performing the same specific activities at precisely the same time each day, singing the same song over and over again, and not allowing interruptions in speech. Some patients also develop exploitative behaviors, such as repeatedly opening and closing the TV, doors and windows, cutting books with scissors on the table, and making swatting motions when they see a fly swatter. Some patients have reduced speech, do not initiate speech, and respond briefly to questions. Besides frontotemporal dementia, Lewy body dementia; certain metabolic encephalopathies, such as Hashimoto’s encephalopathy; and paralytic dementia caused by syphilis can also present with the above mental symptoms, which should be taken seriously and treated promptly at the hospital.