Andie had bipolar disorder.
- I mean, she behaves in a increasingly erratic way across seasons 3 and 4.
Series is being told in flashback.
Would explain the Dawson Casting
- And the voluble behaviour of the protagonists.
http://tvtropes.org/pmwiki/pmwiki.php/WMG/DawsonsCreek
FollowingGo To
Would explain the Dawson Casting