Schizophrenia treatment responses follow distinct trajectories

By Joanna Lyford, Senior medwireNews Reporter

The positive and negative symptoms of schizophrenia generally change in parallel with each other, shows research, supporting the notion that the different symptom domains of the condition have a shared underlying pathology.

The findings are reported by Lei Chen (Lilly Research Laboratories, Indianapolis, Indiana, USA) and team, who identified a total of 11 distinct symptom trajectories among people with schizophrenia.

“Further research on the association between these treatment response trajectory subgroups and the underlying determinants (i.e., treatment choice, pathophysiology, and etiology indicators) may help inform clinical practice or aid the effort to develop targeted treatment of schizophrenia,” they write in BMC Psychiatry.

Chen et al analyzed information on 399 patients with schizophrenia spectrum disorder who had participated in a randomized clinical trial. All patients began treatment with first- or second-generation antipsychotics and were assessed seven times during the 1-year study, at weeks 0, 1, 3, 9, 21, 33, and 49.

The team tracked the trajectory of positive and negative symptoms for each participant, assessed for severity using the Positive and Negative Symptoms Scale.

This revealed a total of four distinct negative symptom trajectories and three positive symptom trajectories, giving rise to 11 combined trajectory patterns (no patients followed the 12th potential trajectory). Negative and positive symptom trajectories moved generally in parallel, write the authors, and changes in negative and positive symptoms significantly correlated.

Also, at every time point, negative symptoms were generally more severe than positive symptoms.

Analysis of the combined negative and positive symptom trajectories suggested that 98% of patients generally followed one of three distinct disease courses: dramatic and sustained early improvement in both negative and positive symptoms (18%); mild and sustained improvement in negative and positive symptoms (59%); or no improvement in either negative or positive symptoms (21%).

The final 2% of patients followed idiosyncratic courses.

“These findings suggest that changes in negative and positive symptoms are neither inversely related nor independent with each other, at least in chronically ill patients treated in the United States, who represent the study population,” write Chen et al.

They conclude: “These findings support the Howes-Kapur hypothesis that there may be a common upstream pathological process that leads to different symptom manifestations in schizophrenia.”

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