A clock is striking 4:00am at a psychiatric clinic. The darkness, the silence, and absence of people makes it look like a morgue. A young mental health professional is sitting in a chair drinking a cheap vodka alone. He doesn’t resembles a person who is certified in treating mental disorders. He has dark straight hair that is long enough to give him a teenage look. The only qualification seems to be is his sharp and intellectual look in his eyes. He is sitting in the middle of the clinic's cafeteria. The moon is the only thing that illuminates his emotionless face.
I removed the striking of the clock. Psychiatric clinics aren't likely to have clocks that strike, especially at four in the morning, especially in the cafeteria.
Also, I switched from present progressive to simple present tense. That feels more engaging to me.
I'm not sure what to do with the three sentences in the middle. I can't figure out the viewpoint. It can't be omniscient, because the narrator judges too many things from a narrow perspective:
These judgments are wholly unreliable. So is the narrator an actual, unreliable person observing the lone young man? If so, the young man isn't alone.
Or is this an omniscient narrator telling us that we readers might judge the young man in these ways? If so, that's mighty condescending of the reader.
Not knowing what the viewpoint is, I didn't know what to do with those three sentences.
As it turns out, I think the paragraph reads delightfully without those observations and judgments. Perhaps the information about the young man's looks could be restored into the paragraph somehow. But it might be better to add it in subsequent paragraphs—either without the judgments, or after we are more clearly introduced to the narrator who is doing the judging.
Use four a.m. (or just four as it becomes clear the scene is at night). (Also, most clocks don't strike differently for a.m. versus p.m.)
A young mental health professional -- Toss it and introduce him by name, instead. The next sentence implies his profession, and we get he's young from teenage look.
You don't need to say alone, since you've already told us there is nobody else.
What is a sharp and intellectual look, especially in the eyes of someone who is getting drunk in the darkness? And it's not a qualification.
He is sitting in the middle of the clinic's cafeteria -- You said "He is sitting" earlier, so just drop this sentence and combine with the earlier one to establish the setting.
Hope this helps.
I apologize that this is more criticism than direct recommendations for improvement; hopefully I've pointed out what needs to be improved, and made it clear roughly how. If I can, I'll be back later to give an example of a rewrite according to my above comments.
Hope these comments are helpful :)