The most obvious symptoms of brief psychotic disorder include:

Hallucinations: Hallucinations are sensory perceptions of things that aren't actually present, such as hearing voices, seeing things that aren't there or feeling sensations on your skin even though nothing is touching your body.
Delusions: These are false beliefs that the person refuses to give up, even in the face of contradictory facts.
Other symptoms of brief psychotic disorder include:

Disorganized thinking
Speech or language that doesn't make sense
Unusual behavior and dress
Problems with memory
Disorientation or confusion
Changes in eating or sleeping habits, energy level, or weight
Inability to make decisions