Magnetic resonance imaging predictors of treatment response in first-episode schizophrenia

Abstract

Identifying neurobiological predictors of response to antipsychotics in patients with schizophrenia is a critical goal of translational psychiatry. Few studies, however, have investigated the relationship between indices of brain structure and treatment response in the context of a controlled clinical trial. In this study, we sought to identify magnetic resonance (MR) imaging measures of the brain that predict treatment response in patients experiencing a first-episode of schizophrenia. Structural MR imaging scans were acquired in 39 patients experiencing a first-episode of schizophrenia with minimal or no prior exposure to antipsychotics participating in a double-blind 16-week clinical trial comparing the efficacy of risperidone vs olanzapine. Twenty-five patients were classified as responders by meeting operationally defined treatment response criteria on 2 consecutive study visits. Fourteen patients never responded to antipsychotic medication at any point during the clinical trial. MR imaging scans were also acquired in 45 age- and sex-matched healthy volunteers. Cortical pattern matching methods were used to compare cortical thickness and asymmetry measures among groups. Statistical mapping results, confirmed by permutation testing, indicated that responders had greater cortical thickness in occipital regions and greater frontal cortical asymmetry compared with nonresponders. Moreover, among responders, greater thickness in temporal regions was associated with less time to respond. Our findings are consistent with the hypothesis that plasticity and cortical thickness may be more preserved in responders and that MR imaging may assist in the prediction of antipsychotic drug response in patients experiencing a first-episode of schizophrenia.

Fig. 1.

An Illustration of the Regions-of-Interest Defined by the LPBA40 Atlas Used in the Current Study.

Fig. 2.

Significant (P < .05, Uncorrected) Differences in Cortical Thickness Encoded in Color in Responders Compared With Healthy Volunteers (Panel A), Nonresponders Compared With Healthy Volunteers (Panel B), And Responders Compared With Nonresponders (Panel C).

Fig. 3.

Significant Correlations Between Time to Response And Cortical Thickness Among The Responders (N = 25). Note: Hot colors denote negative correlations and cool colors denote positive correlations.

Fig. 4.

Significant Differences (Uncorrected P values Encoded in Color) in Asymmetry Indices Encoded in Color in Responders Compared With Healthy Volunteers (Panel A), Nonresponders Compared With Healthy Volunteers (Panel B), and Responders Compared with Nonresponders (Panel C).

Fig. 5.

Asymmetry Indices Averaged at Thousands of Hemispheric Surface Points Within Responders And Nonresponders Separately. Note: Cool colors represent larger distances from the origin in the right compared with the left hemisphere (reflecting right frontal protrusions). Hot colors represent larger distances from the origin in the left compared with the right hemisphere (representing left occipital protrusions).