Because it is difficult to quantify the experience of psychosis, progress toward understanding its biology has been limited. A new study indicates that mice may be a scientifically useful model. When exposed to ketamine and trained to expect a reward when they heard a specific sound, mice behaved similarly to humans experiencing auditory hallucinations. The mice also showed increased levels of dopamine during the study activity and resumed normal behavior after being treated with the antipsychotic haloperidol, a further similarity to humans. If further research proves that the mouse model is reliable it may be a valuable new avenue to increase our understanding of conditions like schizophrenia. For more information, see the study in Science.