Bad Status Effects #1
confuse - you lose control of your character
berzerk - although strength increases, character can only attack
stop - character cannot move
poison - hp gradually decreases
sleep - character falls asleep and cannot move
slow - atb fills up slowly

Bad Status Effects #2
heat - character ko if takes any action
freeze - char becomes frozen and gets ko if physically attacked
mini - character shrinks, reduces battle power and defense

Very Bad #1
petrify - character becomes petrified and cannot move
venom - hp and mp gradually decrease and character cannot move
virus - character cannot gain xp or ap after battle
silence - character cannot use magic

Very Bad #2
darkness - vision is impaired and physical attack accuracy decreases
trouble - damage char receives transfers to other characters
zombie - healing items and magic cause damage to character

Good Status #1
auto life - character revives from ko automatically once during battle
regen - hp are gradually restored
haste - atb gauge fills up faster
float - character floats and does not receive earth damage

Good Status #2
shell - damage from magic attacks decreases
protect - damage from physical attacks decreases
vanish - character vanishes and cannot be hit by physical attacks, character reappears if hit by magic
reflect - magic is reflected at the caster, some magic cannot be reflected.

Final Fantasy IX Walkthrough Index