Neural correlates of movement generation in the 'at-risk mental state'.

OBJECTIVE

People with 'prodromal' symptoms have a very high risk of developing psychosis. We examined the neurocognitive basis of this vulnerability by using functional MRI to study subjects with an at-risk mental state (ARMS) while they performed a random movement generation task.

METHOD

Cross-sectional comparison of individuals with an ARMS (n = 17), patients with first episode schizophreniform psychosis (n = 10) and healthy volunteers (n = 15). Subjects were studied using functional MRI while they performed a random movement generation paradigm.

RESULTS

During random movement generation, the ARMS group showed less activation in the left inferior parietal cortex than controls, but greater activation than in the first episode group.

CONCLUSION

The ARMS is associated with abnormalities of regional brain function that are qualitatively similar to those in patients who have recently presented with psychosis but less severe.