Certification
- Australia:MA15+ (TV rating, Season 1-4 DVD)
- Canada:16+ (Quebec)
- Canada:18+ (TV rating)
- Germany:18 (self-applied)
- Ireland:18 (TV rating)
- Netherlands:12 (self-applied)
- New Zealand:R16 (TV rating, Season 1-4 DVD)
- Russia:18+
- Spain:18
- Sweden:16+ (self-applied)
- United Kingdom:18 (some episodes, Season 1 DVD)
- United Kingdom:15 (some episodes, Season 2-3 DVD)
- United States:TV-MA
- United States:TV-MA (V, some episodes)