| Stage 1. People in the first stage forget recent events or new information, particularly names and places. For example, they might forget the name of a famous film star or how to get home from a familiar place. This first stage is similar to mild cognitive impairment—even experts cannot always tell the difference. |
| Stage 2. Generalized confusion develops, with deficits in concentration and short-term memory. Speech becomes aimless and repetitious, vocabulary is limited, words get mixed up. Personality traits are not curbed by rational thought. For example, suspicious people may decide that others have stolen the things that they themselves have mislaid. |
| Stage 3. Memory loss becomes dangerous. Although people at stage 3 can care for themselves, they might leave a lit stove or hot iron on or might forget whether they took essential medicine and thus take it twice—or not at all. |
| Stage 4. At this stage, full-time care is needed. People cannot communicate well. They might not recognize their closest loved ones. |
| Stage 5. Finally, people with AD become unresponsive. Identity and personality have disappeared. Death comes 10 to 15 years after the first signs appear. |