Successful antipsychotic treatment may alter striatal connectivity

By Eleanor McDermid, Senior medwireNews Reporter

Connectivity within the striatum changes as psychotic symptoms improve in patients treated with second-generation antipsychotics, a study shows.

“These data further characterize the pathophysiology of psychosis and support the role of neuroimaging as a potential biomarker for clinical response”, say Anil Malhotra (Zucker Hillside Hospital, New York, USA) and co-authors.

At the study baseline, the 24 patients with first-episode psychosis had received a median of 1 day of treatment with a second-generation antipsychotic. The researchers created functional connectivity maps for 12 regions of interest within the striatum using data from 24 mentally healthy controls who were matched to the patients for age, gender, education and handedness.

There were no differences in connectivity between the patients and controls at baseline. Controls showed no changes in connectivity over the subsequent 12 weeks of antipsychotic treatment, and the patient group overall showed only one, involving the right ventral caudate.

However, there were significant connectivity changes that related to treatment response, the team reports in JAMA Psychiatry.

The patient group had a significant reduction in positive symptoms on three items of the Brief Psychiatric Rating Scale–Anchored version (unusual thought content, hallucinations and conceptual disorganisation), from an average of 11.0 to 5.6 points.

Positive symptoms did not correlate with connectivity at baseline or follow-up, but as symptoms improved, functional connectivity increased between the right dorsal caudate and the orbitofrontal cortex, anterior cingulate and right dorsolateral prefrontal cortex; between the right ventral caudate/nucleus accumbens and the left hippocampus; and between the right ventral rostral putamen and the anterior cingulate and right anterior insula.

Changes in connectivity to the anterior cingulate imply “a role for error monitoring and cognitive control in recovery from psychotic symptoms”, comment Malhotra et al.

Some connections reduced as psychosis improved, specifically those between the right ventral caudate/nucleus accumbens and the bilateral superior parietal lobule and supramarginal gyrus, and between the left ventral caudate and the superior parietal lobe.

“As hypothesized, our results demonstrated that symptomatic improvement of psychosis was associated with alterations in functional connections of the striatum, a structure consistently implicated in the pathophysiology of psychosis and a shared site of [dopamine] D2 receptor binding of all antipsychotic agents”, say the researchers.

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