In all cases you will receive advice and help from the responsible youth welfare office and the addiction counseling centers.
Youth welfare offices in Sachsen-Anhalt: https://ms.sachsen-anhalt.de/themen/familie/familienratgeber/adressen/jugendaemter/
Important information can be found here: https://www.suchtfragen.de/ and https://www.hls-online.org/
Addiction counseling centers in Sachsen-Anhalt can be found on the website of the Country office for addiction issues in Sachsen-Anhalt: http://www.ls-suchtfragen-lsa.de/suchthilfewegweiser/