Possible Clues:

• Condition for Marc Summers, notably
• Neat freak's condition, e.g., for short
• Cause of some repetitive behavior, in brief
• 'Monk' condition
• Neatnik's diagnosis, at times
• Too focused, for short
• Anxious med. condition for TV's Monk
• Condition for TV's Monk: Abbr
• Last of 26
• Anxiety issue, briefly