This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Psychiatry
Modafinil is approved by FDA for treatment of all except : 
Select and explain. 
A. Obstructive sleep apnea syndrome (OSAS), B. Shift work syndrome (SWS), C. Narcolepsy, D. Lethargy in depression
D: Lethargy in depression
Answer: D: Lethargy in depression 
Explanation: Modafinil (Provigil) :

Modafinil is an oral drug that is used for improving wakefulness in patients with excessive sleepiness.
Modafinil is used to promote wakefulness in patients with excessive sleepiness associated with :


Narcolepsy.
Obstructive sleep apnea/hypopnea syndrome and
Shift work sleep disorder.


The exact mechanism of action of modafinil is not clear. It seems that modafinil increases the release of monoamines specifically the catecholamines (norepinephrine and dopamine) from the presynaptic terminals. However, modafinil also elevates hypothalamic histamine levels (in contrast to amphetamine-like stimulant which only releases catecholamines, but not histamine).