From Bulbapedia, the community-driven Pokémon encyclopedia.
According to [http://www.angelfire.com/pa4/jman/held_item.html#misc this fansite], Berserk Gene only confuses the holder for the standard duration in Stadium 2. [http://upcarchive.playker.info/0/upokecenter/content/pokemon-gold-version-silver-version-and-crystal-version-held-items.html UPC] seems to imply the same thing (without being explicit). Could someone check Stadium 2 to confirm this? --[[User:SnorlaxMonster|<span style="color:#A70000">'''Snorlax'''</span>]][[User talk:SnorlaxMonster|<span style="color:#0000A7">'''Monster'''</span>]] 12:59, 22 August 2017 (UTC)