"The discussion ends."

[Axelels]

de discussie stopt? Is this not possible?

[MShafiei1]

Eindigt of beeindigt?

[Tijsdv]

Eindigt.

'Beëindigd' (NOT beëindigt, which you proposed. The -t ending doesn't exist for this verb in this form. These are hard, I know!) means 'ended'. E.g.: De discussie is beëindigd = The discussion has ended.

[El2theK]

Beëindigen certainly can be conjugated like any other verb.

The difference is:

• Eindigen = intransitive
• Beëindigen = transitive

So by using beëindigen you would need an object that the subject ends/finishes, e.g. Hij beëindigt zijn carrière (He ends his carreer).

[ArthurLace4]

Does "De discussie is afgelopen" imply the same meaning?

[MentalPinball]

I'd say so, but you're using a passive structure (and the original sentence was in active voice).