If the magic damage doesn't list bludgeoning, slashing, or piercing damage types, it'll go through DR.
As per this FAQ:
Damage Reduction: How does DR interact with magical effects that deal bludgeoning, piercing, or slashing damage?
Although the Bestiary definition of Damage Reduction (page 299) says "The creature takes normal damage from energy attacks (even nonmagical ones), spells, spell-like abilities, and supernatural abilities," that's actually just referring to damage that isn't specifically called out as being of a particular type, such as fire damage or piercing damage. In other words, DR doesn't protect against "typeless damage" from magical attacks.
However, if a magical attack specifically mentions that it deals bludgeoning, piercing, or slashing damage, DR affects that damage normally, as if it were from a physical weapon. (Otherwise the magical attack might as well not have a damage type, as it would only interface with B/P/S damage in a very few corner cases, such as whether or not an ooze splits from that attack.)
For example, the ice storm spell deals 3d6 points of bludgeoning damage and 2d6 points of cold damage. If you cast ice storm at a group of zombies, the zombie's DR 5/slashing protects them against 5 points of the spell's bludgeoning damage. Their DR doesn't help them against the spell's cold damage because DR doesn't apply to energy attacks.
Actually, Mind thrust is a spell (actually a power), so by default and unless the damage is typed slashing/piercing/blunt , DR does not help against it. Given that it's a telepathy power and the damage would be typed as psychic damage in 4e, it obviously bypasses DR completely.
I believe Balancer is referring to the Mind Thrust line of psychic spells of Occult Adventures book, not the 3rd party Mind Thrust from Dreamscarred Press (or 3.5 Psionics).
The only time a spell's damage is subject to DR is when the damage is explicitly spelled out as typed (bludgeoning, for instance) OR it is a conjuration that deals untyped damage.
In the first case, it's because the author provided you type for that reason. In the second case, it's because conjured items are real and do what they do.
Basically, conjuring an anvil over someone will deal bludgeoning damage (subject to DR) because it's real, while evoking a force to crush them from above won't because it's the spell doing damage... unless the spell explicitly says it does bludgeoning damage.
Either way, mind thrust (the power or the spell) isn't subject to DR.