Does cannabis affect the capacity to work and concentrate on tasks more so than other drugs?

Negative effects: Pot, especially if used chronically, generally causes decreased focus and performance -- and especially decreased motivation. As to comparing it to other drugs... It depends on dosing, as well as what the other drugs are. There are street drugs that are worse, and there are some that may have little if any adverse effect on work and concentration.

Depends on the drug: Cannabis is well known as an inhibitor of ambition, capacity to work and concentration. Using enough of a different drug might affect these capacities in a similar fashion.