Related Clues:

• Madness
• Unmitigated folly
• Craziness
• Psychopathy
• Extreme foolishness
• Lunacy
• Utter madness
• Psychopathy, e.g.
• Mental illness
• Lunacy, madness
• Lunacy, derangement
• Mental derangement
• Perhaps where there's a nit there's a nut
• 'Mind, it's not right, but it's only a tiny sin (8)'
• Extreme folly