We say "commit suicide" (without the article "a"). "Commit a suicide" is incorrect.

We say "commit suicide" (without the article "a"). "Commit a suicide" is incorrect.

He committed suicide.

He committed a suicide.

Note that we use the verb "commit". We don't say "make suicide" or "do suicide".

His father tried to commit suicide on several occasions.

His father tried to do/make suicide on several occasions.

But you can use the expressions “attempt suicide” or “die by suicide”.

My sister attempted suicide yesterday.

She also tried to kill her boyfriend before dying by suicide.

The word “suicide” can also be used to describe another noun. In such a situation, add the article “a” or another determiner according to the usual rules.

Peter shot his wife and himself in a suicide pact.

The suicide rate among males declined by 3%.

You can also use a determiner (this, that, many, different, several, etc.) before the plural form (suicides).

The unfortunate reality is that this situation is the cause of many suicides.

But omit the article if you are speaking about "suicides" in a general sense.

Suicides among young people continue to be a serious problem.