Neuroimaging could predict psychosis treatment response

By Eleanor McDermid, Senior medwireNews Reporter

Assessing white matter integrity in patients with first-episode psychosis may predict who will respond to antipsychotic treatment, research suggests.

“The early discrimination between responders and non-responders is […] of crucial importance, as it can reduce disability, healthcare costs, and eventually improve long-term outcome,” say lead researcher Tiago Reis Marques (King’s College London, UK) and co-workers.

They found that white matter integrity was significantly reduced in patients who subsequently failed to respond to antipsychotic treatment, but was indistinguishable from controls in those who responded.

“In combination with other neuroimaging and clinical measures, these findings could considerably help patient stratification in psychiatry, ultimately allowing individualized patient management from the time of the first presentation to services,” writes the team in Brain.

A total of 63 patients underwent diffusion tensor imaging before starting antipsychotic medication, exhibiting significant reductions in white matter integrity relative to 53 mentally healthy controls. After 12 weeks of treatment, 30 patients had achieved a clinical response, determined by direct assessment of Positive and Negative Syndrome Scale (PANSS) scores or via the Personal and Psychiatric History Schedule.

The 33 patients who did not respond had significantly reduced white matter integrity relative to the responders, even after accounting for PANSS scores and duration of follow-up.

“The most affected tracts comprised associative fibres, including the uncinate, stria terminalis and superior frontal-occipital tract; commissural fibres such as the corpus callosum; and several projections fibres, such as the internal and external capsule and corona radiata,” says the team.

The nonresponders also had significant white matter integrity reductions compared with controls, but the responders did not.

Twenty treatment responders and 22 nonresponders had repeat scans after 12 weeks of treatment. Both groups showed significant increases in white matter integrity relative to baseline, and this correlated with the cumulative dose of antipsychotic medication. Nonresponders still had significantly lower white matter integrity than responders at this point, but the differences were less pronounced than at baseline.

The researchers note that white matter integrity in regions that differed in responders versus nonresponders was lower in patients with higher PANSS scores, both at baseline and follow-up, suggesting these changes may relate more to the underlying pathophysiology than symptomatology, and are therefore little affected by treatment.

But they caution that “we cannot exclude that the altered white matter integrity was already present in non-responders long before illness onset, reflecting a different, possibly neurodevelopmental origin.”

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