[OodaThunkett]

Strange jerky head movements?

Yes - 1 point
No - 0 points

Talking to himself?

Yes - 1 point
No - 0 points

Now add up your score.

2 points - call the police.
1 point - observe carefully until he either starts/stops making strange jerky head movements or starts/stops talking to himself, then redo test.
0 points - relax.