Well more specifically CBD causes the "couch lock" effect and its very prominent in trichomes that are in the amber stage. Clear trichomes contain a higher amount of thc thus giving you a "racing high". To add, strains with a higher percentages of sativa in their genetics will have very low numbers of amber trichomes even when the bud itself is completely ripe ie: fading leaves, receding of all pistils, and complete swelling of the caylxes. Trichomes in indica leaning genetics by the time harvest arrives (totally by the looks of the buds and the plant) will have a much higher number of amber trichs... This is what gives sativas and indicas their distinctive "highs".
Beyond the amber stage is when the desired effects start to waste away.
To my knowledge this is the way it works.
With all that said, I dont bother checking trichs any longer in regards to harvesting times. They are still fun to look at