The answer: yes.

My sister got me a Kakuro book a few weeks ago. It's a more complicated version of Sudoku that involves some basic math skills. I was very glad to get it as Sudoku was becoming quite boring.

Anyway, I took an Ambien for the flight to London, although I only slept for a couple of hours. The rest of the time I tried playing Kakuro. And I played some that night at the hotel. In a day's worth of travelling, I could only finish three games. On each game, I made at least one mistake and I eventually screwed up the puzzle so much I had to abandon it unfinished.

The next day we flew from London to the Czech Republic. In a matter of a couple of hours, I finished three puzzles without any errors.

Yikes.

Stay away from drugs, kids.