A new study has identified six variables in the early treatment of schizophrenia patients to predict the oncoming need for switching the antipsychotic medication in order to meet long-term treatment needs.
As mainstays in the clinical treatment and management of schizophrenia, antipsychotic medications often have to be switched due to less than optimal responses from patients or lack of tolerance.
Recently published in the journal BMC Psychiatry, Haya Ascher-Svanum of Eli Lilly and Company and a team of researchers noted that minimal data exists on the frequency, timing and predictors of medication changes in schizophrenia patients.
“Previous studies evaluating predictors of switching assessed a relatively narrow range of variables and did so for patients who may not be representative of those treated in usual outpatient care settings,” the team wrote, adding that “furthermore, previous research assessed predictors of medication switching at discrete time points, thus providing a time-limited context for this dynamic treatment practice.”
Data on 648 patients aged 18 or older was analyzed. Participants in the antipsychotic treatment study were diagnosed with schizophrenia, schizoaffective, or schizophreniform and remained on their initially assigned medication for at least eight weeks.
Following the eight-week mark, the patients’ medication was changed if clinically warranted.
Researchers assessed baseline characteristics using standard psychiatric measures and reviews of medical records that included baseline sociodemographics, comorbid psychiatric and non-psychiatric conditions, body weight, clinical and functional variables.
Change scores were taken during the first two weeks on standard efficacy and tolerability measures, and cox proportional hazards modeling was used to identify the best predictors of switching from the initially assigned antipsychotic medication.
Approximately one-third of the patients—equating to 191 total—switched antipsychotics before the conclusion of the one-year study.
Researchers identified six characteristics as the best predictors of switching including lack of antipsychotic use in the prior year, pre-existing depression, female gender, lack of substance use disorder, worsening of akathisia, and worsening of symptoms of depression and anxiety during the first two weeks of antipsychotic therapy.
“Switching antipsychotics appears to be prevalent in the naturalistic treatment of schizophrenia and can be predicted by a small and distinct set of variables,” the team concluded. “Interestingly, worsening of anxiety and depressive symptoms and of akathisia following two weeks of treatment were among the more robust predictors of subsequent switching of antipsychotics.”
For the early variables of anxiety/depression symptoms and akathisia, researchers found that for every one-point increase in the positive and negative syndrome scale (PANSS) depression/anxiety subscale score, the risk for switching increased by 5.1 percent, and for every one-point increase in the Barnes Akathisia objective score, the risk for switching increased by 34.5 percent.
A total of 304 patients completed the one-year study without changing the initially-prescribed antipsychotic, and a total of 153 dropped out of the study without switching.
Other findings revealed that women were 37.6 percent more likely to switch than men, and patients with a pre-existing depression diagnosis were 48.4 percent more likely to switch than those without the pre-existing condition.
Also, those who had undergone antipsychotic treatment in the prior year were 38.3 percent less likely to switch, and those with a substance use diagnosis were 26.9 percent less likely to switch than those without the illness.
Researchers suggested that “further longitudinal studies are needed to evaluate and replicate these findings.”
Source: BMC Psychiatry