Learn Hardcore Spanish (Latin America): No todos necesitan ver a una psiquiatra, pero saber que existe esa opción me da tranquilidad. - Not everyone needs to see a psychiatrist, but knowing that option exists gives me peace of mind.

Spanish normally puts no before the verb, but when you say no todos + verb, you’re really saying “it’s not true that everyone …” which matches the English idea of “Not everyone needs …”

Why is it ver a una psiquiatra and not just ver una psiquiatra? What is that a doing there?

That a is the “personal a” in Spanish.

You use a before a direct object that is a specific person (or people), even when they are not named:

Ver a una psiquiatra – see a psychiatrist (a person)
Ver a mi mamá – see my mom
Ver a los niños – see the children

But you don’t use it with things:

Ver una película – see a movie
Ver un edificio – see a building

So ver a una psiquiatra is correct because a psychiatrist is a person, even though it’s “a psychiatrist” and not “the psychiatrist.”

Why is it una psiquiatra (feminine) and not un psiquiatra? Is that just saying the psychiatrist is a woman?

Yes.

In Spanish, many profession nouns like psiquiatra have the same form for both genders, and what changes is the article:

un psiquiatra = a male psychiatrist
una psiquiatra = a female psychiatrist

So this sentence is imagining or referring to a female psychiatrist.

If you wanted to speak more generically, people often say:

ver a un psiquiatra (generic / default masculine)
or ver a una persona psiquiatra (very explicitly neutral, but much less common and sounds a bit “corrective”).

In everyday Latin American Spanish, generic talk about the profession usually defaults to un psiquiatra unless there is a reason to stress that she is a woman.

In English we say “see a psychiatrist” meaning “go for an appointment.” Does ver a una psiquiatra mean the same thing, or just literally “to see her”?

Ver a una psiquiatra can mean both, depending on context:

Literal “to see” (with your eyes):
- Ayer vi a una psiquiatra en la tele.
  I saw a psychiatrist on TV yesterday.
“See” in the sense of “have an appointment with / consult” – just like English:
- Estoy pensando en ver a una psiquiatra.
  I’m thinking of seeing a psychiatrist.

You will also hear:

Ir al psiquiatra – literally “go to the psychiatrist,” often used as “to be in treatment / go regularly.”

In your sentence, context makes it clear it’s about consulting a psychiatrist as an option, not just literally seeing one somewhere.

Why is it pero saber que existe esa opción without an explicit subject like “el saber”? Who is doing the “knowing”?

Here, saber is used as an infinitive acting as a noun, and the whole phrase saber que existe esa opción is the subject of da:

Saber que existe esa opción me da tranquilidad.
→ Knowing that that option exists gives me peace of mind.

In English, -ing verbs (like knowing) can act as nouns. In Spanish, the infinitive (saber) plays that role.

You could say El saber que existe esa opción me da tranquilidad, and it’s correct, but:

Saber que… (without el) sounds more natural and lighter in everyday speech.
El saber que… can sound a bit more formal or heavy.

The person who knows is shown by me in me da tranquilidad (“gives me peace of mind”).

Why is it que existe esa opción and not que exista esa opción? Why the indicative and not the subjunctive?

After saber que, you normally use the indicative when you’re talking about something real, known, or factual:

Saber que existe esa opción…
= Knowing that this option does exist (it’s considered a fact).

You use the subjunctive (exista) with verbs that express doubt, wish, uncertainty, or nonexistence:

Dudo que exista esa opción.
I doubt that option exists.

So:

Sé / saber que existe → I know it exists → indicative (exists in reality).
Dudo / no creo que exista → I doubt it exists → subjunctive (uncertain / hypothetical).

In your sentence, the speaker is reassured precisely because they believe the option really does exist, therefore existe.

Could you also say esa opción existe instead of existe esa opción? Is there a difference?

Yes, you can say both:

saber que existe esa opción
saber que esa opción existe

They are both grammatically correct and natural. Any difference is very subtle:

existe esa opción slightly emphasizes the existence first.
esa opción existe slightly foregrounds “that option” first.

In everyday speech, both word orders are fine; the choice here is mostly style, not grammar.

What exactly is me da tranquilidad doing grammatically? Why me, and why da?

Dar (“to give”) is being used in a figurative way:

X da tranquilidad a alguien = X gives someone peace of mind / makes someone feel calm.

Breakdown:

saber que existe esa opción → subject (the thing doing the giving)
da → 3rd person singular of dar (“gives”)
tranquilidad → direct object (what is given)
me → indirect object (to whom it is given → to me)

So literally:

Saber que existe esa opción me da tranquilidad.
= Knowing that that option exists gives peace-of-mind to me.

This “dar + noun” structure is very common:

Me da miedo. – It scares me. (It gives me fear.)
Me da esperanza. – It gives me hope.
Me da vergüenza. – It embarrasses me.

Why tranquilidad and not paz mental or something else? Is there a nuance?

Tranquilidad is a very common, flexible word in Spanish that covers:

calmness
peace of mind
the opposite of anxiety / worry

In this context, me da tranquilidad is the natural default phrase.

Alternatives exist, but they’re either less common or slightly different in tone:

me da paz mental / paz – understandable, but sounds a bit more literal or formal; less idiomatic in casual speech.
me hace sentir tranquilo/a – focuses more directly on the feeling, not just “peace of mind” as a concept.

So tranquilidad is chosen because it’s the usual, idiomatic way to express “peace of mind / a sense of calm” in this kind of sentence.

Could the sentence use tienen que or deben instead of necesitan? What’s the difference between necesitar, tener que, and deber here?

All three are related but not identical:

necesitar + infinitive – need to
- No todos necesitan ver a una psiquiatra.
  Not everyone needs to see a psychiatrist.
  Neutral; just says it isn’t necessary for everyone.
tener que + infinitive – have to / must (external obligation)
- No todos tienen que ver a una psiquiatra.
  Not everyone has to see a psychiatrist.
  Sounds more like an external rule or obligation (doctor’s orders, social pressure, etc.).
deber + infinitive – should / ought to / must (moral or logical duty)
- No todos deben ver a una psiquiatra.
  Not everyone should see a psychiatrist.
  Adds a sense of recommendation, appropriateness, or moral / logical duty.

In your original sentence, necesitan is best because it talks about actual need in a neutral way, not obligation or advice.