Don’t try to lift the diver out of the water using your BCD. Always inflate the diver’s BCD first because you may need to drop back below the surface to get away or provide some other form of assistance. Once the panicked diver is buoyant, you can move away and assess your options. You have gained control of the situation, and now you can make decisions about your next course of action.
This is an excerpt from Scuba Diving Safety.