Critical Reasoning

The symptoms of mental disorders are behavioral, cognitive, or emotional problems. Some patients with mental disorders can be effectively treated with psychotherapy. But it is now known that in some patients mental disorders result from chemical imbalances affecting the brain. Thus these patients can be effectively treated only with medication that will reduce or correct the imbalance.

The argument depends on assuming which one of the following?
(A) Treatment by psychotherapy can produce no effective reduction in or correction of chemical imbalances that cause mental disorders.
(B) Treatment with medication always shows faster results for patients with mental disorders than does treatment with psychotherapy.
(C) Most mental disorders are not the result of chemical imbalances affecting the brain.
(D) Medication is always more effective in treating patients with mental disorders than is psychotherapy.
(E) Treatment with psychotherapy has no effect on mental disorders other than a reduction of the symptoms.

Hi,

[spoiler]I found it difficult to select between A and D.
OA: A and IMO : D[/spoiler]

My Take: Some pat. (m.dis) = treated with psychotherapy.
Contrast: In those patients disorders is due to chemical imbal.
Concl: Only medication can treat such patients by reducing or correcting the imbalance.

Assumption: psychotherapy is not as effective as medication in reducing or correcting the imbalance.
So confused with D and A ,can you please help me to explain why d is wrong or less effective than A.

Hi gaurav.

The first thing you need to do when dealing with assumption question is, identify both the evidence and the conclusion. Here they are.

Conclusion (as you said) : ONLY medication can be an effective treatment for patients acquiring mental disorders from chemical imbalances in the brain. Notice that I put emphasis on the word "ONLY", and you will see why.

Evidence : some patients with mental disorders can be treated with psychotherapy. However, there are new cases in which people suffer mental disorders as a result from chemical imbalances.

What would be the assumption?

You will see why A is correct, and there are a number of strategies that can help you identify A, and NOT D. as the correct answer.

Strategy #1 : an assumption should fill the gap between the evidence and the conclusion. Choice A does so by saying that, although it works on some other cases of patients with mental disorders, treatment by psychotherapy can NOT effectively reduce or correct the chemical imbalances. Thus ... (and, this is where the conclusion comes in) ONLY medication can offer effective reduction in or correction of the chemical imbalances.

Let's see whether choice D fills the gap. Even if it is true that medication always provides more effective treatments for patients with mental disorders than psychotherapy does, we cannot use this as a basis to conclude that ONLY medication will reduce or correct the chemical imbalances, substances that have recently been found to cause mental disorders. Just because medication is a more effective solution does not mean that it is the ONLY solution. Choice D does NOT lead us to the conclusion; thus, it is NOT the assumption.

Strategy #2 : one effective way to determine the assumption is Negation Test. Because the assumption is necessary for the conclusion to stand, negating the assumption will break the conclusion apart. Let's try negating choice A.
If it is true that treatment by psychotherapy CAN produce effective reduction or correction, the conclusion that ONLY medication will reduce or correct the imbalance will no longer be held true. As negating choice A brings down the conclusion, we can be sure that choice A is the assumption.

On the other hand, let's try negating choice D. Even if it is true that medication is NOT always more effective in treating mental disorders than psychotherapy, the conclusion will be left unaffected. Perhaps, medication will NOT be an effective solution for patients with mental disorders resulting from other causes than chemical imbalances. Yet, it will be a perfect solution for patients with mental disorders resulting from chemical imbalances.
In this case, the conclusion is still perfectly valid. Hence, choice D can NOT be the assumption.

I hope it helps...

Wow!

ronaldramlan that is an excellent explanation. You have captured the strategies quite well here and I feel there is nothing left to add.

What I will say for any who are reading this LSAT question is that it is a little more technical and a therefore perhaps a little more difficult than an assumption question on the GMAT. This one is very similar enough to the GMAT and can be studied by GMAT-takers, but it is a tough one.

One take away from this question: Did you notice ronaldramlan's emphasis on the particular wording of the conclusion? This is key. Please mimic this. Students often focus on the smallest details of the background information and then just give some general statement of the conclusion. This will not work. The details of the conclusion can be the difference between one answer and another being correct.

I second what David said - great explanation Ronald!

I'd like to add another general takeaway:

on assumption questions, we're looking for the bare minimum thing that must be true in order for the conclusion to make sense. Accordingly, it will be very rare for an extremely worded answer choice to be correct.

As soon as you see the word "always" in (D), you have cause to eliminate it. We don't care about what's always true - we just need to know what's true in this particular case.

While an extreme statement can be a good answer to a strengthening question, the only time it will be correct in an assumption question is if the author also uses extreme language, which is very rare.

woohoo! I got the question right (although in 2:20

Basically, assumption questions are easy.. Just negate every answer! When the answer is negated, does it hurt the argument? If so, you pretty much have your answer.

for example, the conclusion is: "these patients can be effectively treated only with medication that will reduce or correct the imbalance."

When you negate an answer, simply make something the opposite in a critical portion of the sentence (you can take out a negative word like "no" or "not" or you can add a negative word such as "not":

A). Treatment by psychotherapy can produce no effective reduction in or correction of chemical imbalances that cause mental disorders.

becomes

A) Treatment by psychotherapy can produce no effective reduction in or correction of chemical imbalances that cause mental disorders.

Does that hurt the conclusion? Yer darn tootin it does! (A) is saying that something else can reduce the chemical imbalance. Thus the conclusion assumes this doesnt happen! Assumption questions rely on ruling out possible alternatives to the conclusion.. if you find something that hurts it, you know it is assumed that it doesn't happen.

Pretty much what ronald said in the second portion of his response. NEGATE ASSUMPTIONS! Before this strategy, I would probably get this Q wrong (and spend about 5 minutes in the process of doing so).