Critical Reasoning

According to a review of 61 studies of patients suffering from severely debilitating depression, a large majority of the patients reported that missing a night's sleep immediately lifted their depression. Yet sleep-deprivation is not used to treat depression even though the conventional treatments, which use drugs and electric shocks, often have serious side effects.

Which of the following, if true, best explains the fact that sleep-deprivation is not used as a treatment for depression?

(A) For a small percentage of depressed patients, missing a night's sleep induces a temporary sense of euphoria.
(B) Keeping depressed patients awake is more difficult than keeping awake people who are not depressed.
(C) Prolonged loss of sleep can lead to temporary impairment of judgment comparable to that induced by consuming several ounces of alcohol.
(D) The dramatic shifts in mood connected with sleep and wakefulness have not been traced to particular changes in brain chemistry.
(E) Depression returns in full force as soon as the patient sleeps for even a few minutes.

OA is E. Why not C?

Source- GMAT Test Code 14

pareekbharat86 wrote:According to a review of 61 studies of patients suffering from severely debilitating depression, a large majority of the patients reported that missing a night's sleep immediately lifted their depression. Yet sleep-deprivation is not used to treat depression even though the conventional treatments, which use drugs and electric shocks, often have serious side effects.

Which of the following, if true, best explains the fact that sleep-deprivation is not used as a treatment for depression?

(A) For a small percentage of depressed patients, missing a night's sleep induces a temporary sense of euphoria.
(B) Keeping depressed patients awake is more difficult than keeping awake people who are not depressed.
(C) Prolonged loss of sleep can lead to temporary impairment of judgment comparable to that induced by consuming several ounces of alcohol.
(D) The dramatic shifts in mood connected with sleep and wakefulness have not been traced to particular changes in brain chemistry.
(E) Depression returns in full force as soon as the patient sleeps for even a few minutes.

OA is E. Why not C?

Source- GMAT Test Code 14

We need an answer which explains "why the sleep deprivation method(no sleep) is NOT used to cure depression"
C does not say anything about depression (we are not concerned with impairment of judgement), E provides a link between lack-of-sleep & depression.
Answer : E

Choice C mentions the effects of prolonged loss of sleep. The stimulus speaks of missing a night's sleep. It is not at all clear that the treatment involves prolonged loss of sleep. Also temporary impairment is not as serious as the "Serious side effects" of the other treatments. So that even if choice C did apply, it might still be preferable to the other treatments. Whereas choice E indicates that sleep-deprivation is essentially useless as a treatment since even a few minutes sleep ruins all positive impacts.

Does that help?

David@VeritasPrep wrote:Choice C mentions the effects of prolonged loss of sleep. The stimulus speaks of missing a night's sleep. It is not at all clear that the treatment involves prolonged loss of sleep. Also temporary impairment is not as serious as the "Serious side effects" of the other treatments. So that even if choice C did apply, it might still be preferable to the other treatments. Whereas choice E indicates that sleep-deprivation is essentially useless as a treatment since even a few minutes sleep ruins all positive impacts.

Does that help?

Thanks David. Makes much sense now.

Prolonged loss of sleep can lead to temporary impairment of judgment.
Aside from the change in scope -- PROLONGED loss of sleep ≠ missing ONE NIGHT'S sleep -- notice the following word: can.
That something CAN happen does not mean that it happens FREQUENTLY.
For all we know, the temporary impairment affects only one of every 1,000,000 patients -- a percentage too small to affect the argument.