Final answer:
Alzheimer's disease (AD) is a progressive and irreversible mental condition that causes severe memory loss and cognitive decline. Although there is no cure, cognitive rehabilitation and other interventions can help mitigate its effects.
Step-by-step explanation:
The mental condition that is considered progressive and not reversible is Alzheimer's disease (AD). AD is a neurodegenerative disease that affects the brain and leads to severe memory loss and cognitive decline. It is characterized by the presence of plaques and tangles in the brain, which cause cell death and impair brain function. AD progresses over time, with symptoms worsening from mild to moderate to severe stages. While there is currently no cure for AD, there are strategies to mitigate its effects, such as cognitive rehabilitation and environmental and nutritional interventions.