After the change to squad attacks in the 1.07 the confuse spell has been broken. It still works as advertised on single-troop units, but is broken on multi-troop units.
On units of 3 troops the confuse spell now changes the attack to -50% of the original attack. So a unit with attack +100 with confuse gets an attack of -50. This is not quite consistant though and gets really odd if the unit is confused multiple times. On unit I had that was confused three times ended up with -9000 to attack, when it recovered from all three confuse spells it still had -3000 to attack. When it was confused one time more it had around -16000 to attack, when confused again it suddenly had +21000 to attack.
So confuse affects multi-troops units wrong. It stacks badly, and attacks values wrap arounds at large negative values (since this looks like a signed 16bit value, I will assume it would also wrap around at large positive attack values).