What are the exact negative effects berserk has?

Is there a negative save v mental penalty?

Is that what the focused fury edge prevents, the save v mental?

Is there a penalty against skill learning rates?

I know that there is the 10% penalty to most skills while berserking. It stands to reason that one might learn skills faster while berserking because with the 10% penalty because it means that you'll fail more often thereby increasing the chances you'll get the bigger 'learn from your mistakes' skill gains. Is this true?

Thdth