How do I resolve a critical hit on an attack with a spell that doesn't do direct damage?

Question

I mean spells like Ray of Enfeeblement - what happens if someone rolls critical to attack with them?

It doesn't do damage and instead forces target to pass a fortitude save to place condition on target. In general, rules say that on critical roll to hit - damage should be double, but there is no damage, just condition, so RAW - such critical should be ignored.

In general, I can see following options:

1. Double condition placed on enemy if enemy would fail fortitude save
2. RAW, ignore that critical.
3. Treat enemy's save as one step worse.

I'm mostly interested if there were any official rulings regarding it that I could have missed.

Answer 1

This is covered in the individual spell

The rules for critical hits on p. 278 Core Rulebook tell you how this is handled:

If you critically succeed at a Strike, your attack deals double damage. Other attacks, such as spell attack rolls and some uses of the Athletics skill, describe the specific effects that occur when their outcomes are critical successes.

For example, Ray of Enfeeblement says

If you critically succeed on your attack roll, use the outcome for one degree of success worse than the result of its save.

So in this case, you use an outcome of one degree of success worse than normally for the result of that save. Another spell may have a different resolution.