Some progress has been made towards predicting the onset of schizophrenia, but no one has previously developed a way of guessing which symptoms will arris in a given individual with schizophrenia. Schizophrenia can come with a wide variety of positive and negative symptoms. Positive symptoms are new and bizarre behaviors or perceptions like hallucinations or paranoia, while negative symptoms are the lack of normal healthy behavior like eye contact and coherent speech. A study this month in The Journal of Neuroscience, led by Dr. Paul C. Fletcher, suggests that there may be biological signs of which symptoms a person is most likely to develop.

Dr. Fletcher administered a variety of cognitive tasks to 15 patients before and after giving them either a placebo or ketamine, a drug that temporarily induces both the positive and the negative symptoms of schizophrenia. Subjects were given these same tasks again one month later but received the opposite injection.

Functional MRI scans during placebo conditions were able to predict symptoms during ketamine conditions. Frontothalamic responses to a memory task and bilateral frontal responses to an attention task were correlated with negative symptoms. Frontotemporal activation during language tasks predicted auditory hallucinations and disordered thinking.

Ketamine-induced psychosis is admittedly different from naturally occurring psychosis, but it is very possible that Dr. Fletcher’s work will give doctors both better insight into the nature of schizophrenia and better tools to predict the course of the disease. It now seems likely that divergent progressions of schizophrenia are at least somewhat determined by longstanding neural differences. Families and doctors may me able to preemptively treat some symptoms if they can predict exactly which ones will occur.