^ Yeah, that and also hard Neptune transits for mental issues in general.tNeptune square/opposite Sun, (Mercury,) Mars, Saturn and Pluto especially. (The "masculine" planets, save for Mercury which is neutral.)
tSaturn in hard aspect to Mars, Neptune, Uranus or Pluto can also create a lot of internal discord and/or anxiety.
I'm not completely sure, but perhaps progressions play a role in this, as well (for instance, transiting planets making hard aspects to progressed planets).
ETA: Duh, forgot Pluto and Uranus. Those two can really shake things up (badly). Especially if the Moon is affected.