If you mean Noa Pothoven, it's not true she was given euthanasia; the press reports saying she did were in error. Pothven's request for euthanasia was turned down by Dutch health authorities.

She died at home after she stopped drinking and eating. But apparently she had family and a doctor who went along with this, which is unusual. In most countries, and in most families, a troubled minor so intent on self-destruction would be put in a hospital where she'd be put on IV drip hydration and some sort of forced or tube feeding. And she'd be given intensive in-patient psychotherapy, and every possible anti-depressant med and therapy would be tried, including ECT and IV Ketamine.

In the countries where euthanasia is allowed, it's rarely done for solely psychiatric reasons - it's usually done for people who are suffering horribly due to physical illnesses that are terminal and incurable and the agony of which is not easily reduced by painkillers - like cystic fibrosis, Huntington's and certain advanced cancers.

https://www.insider.com/noa-pothoven-dutch-euthanasia-clinic-address-media-error-2019-6

https://www.insider.com/noa-pothoven-teen-death-puts-spotlight-on-europe-euthanasia-laws-2019-6