I believe that the bible is completely good...but that not all good things are in the bible.
I tend to find that the bible often deals with the "what", but not very directly with the "how". Whether the "what" is premarital/marital counseling, alcohol, parenting, etc...there is definitely some biblical things to bring to the table. Love your wives; honor your husbands. Flee from sin; two are better than one. Spare the rod, spoil the child; lead children not to anger.
That doesn't mean it's wrong to come up with "extra"biblical things. And, as RiverTigriss was saying...it's easy to mis-apply biblical principles and give them a false sense of authority. So what to do? I think we definitely need to find our "what"...our beliefs/world view/truth claims/paradigm from the bible. We should be looking at the world through a Christ-centered lense. As for the "how"...if we understand that a biblical command or principle applies to a situation - then of course we'll use it.
As for your original question...if Dr. Atheist comes up with a good technique for combatting some type of bad behavior...why wouldn't we want to adopt that? Obviously, if some idea of treatment is telling someone to do something sinful, we shouldn't do it. Honestly, though, I would submit that for every good counselling technique found through secular means, we could probably apply some biblical principles to it. Sometimes working a problem backwards is a great way to find a solution.
I guess the main grey area for a lot of folks is over-prescription/diagnosis of psychological things...and for this I would just say to be careful there.