Comment by somenameforme

Subjective cognitive decline is a 'subjective' because it is perceived by the individual themselves. This means one of:

1) Weed dramatically reduces cognitive impairment.

2) Weed dramatically reduces an individual's ability to accurately asses their cognitive ability.

3) People who use weed are, for some other reason, dramatically less likely to suffer from cognitive impairment, or dramatically less able to accurately evaluate their own cognitive state.

4) The study itself is biased or flawed somehow.