Psychosis not otherwise specified diagnosis question...?

I went to conseling about a year ago and the idiot diagnosed me with Adjustment Disorder which is complete bullshit but the reason he did was because in order to take drug tests I had to have a reason. So is there any reason why you would need that diagnosis? And honestly he can't be l00% sure. If you were once psycotic then theres a chance that behavior can reoccure.