Clinical Relationships: While memory is the key cognitive problem in AD, apathy is the key behavioral problem. Apathy is characterized by indifference, disengagement, passivity, and lack of enthusiasm, interest, empathy and interpersonal involvement. Apathy is the most common, one of the earliest and probably the most persistent of behavioral problems in AD. Apathy is the most disturbing behavior to caregivers and has the greatest impact on functional status and caregiver burden.