What psychiatric problems do khat create?

Psychological: addiction, anxiety, aggressiveness and altered sexual drive have been reported.

Same as stimulants: in general. Like the coca leaf or coffee/teas, khat was used mainly by people in East Africa and the middle east as a mild stimulant, being chewed or brewed into tea. Stronger preparations can result in severe anxiety, panic attacks, insomnia and sometimes even paranoia and psychosis. The basic ingredients, cathinones, are similar to "bath salts," which are synthetic stimulants.