Which are the demographic and clinical characteristics of patients who respond to subcutaneous esketamine?

Abstract

The paper by Lucchese et al. (2021), published in Journal of Psychopharmacology, January 9th 2021, provides important information about the use of subcutaneous esketamine in real-world patients. However, some points need to be clarified: First, the majority of patients received the doses of 1 mg/kg, but the paper does not make clear whether those patients were the same who presented a better response. Second, the best response was observed in patients with comorbidity anxiety disorder. The diagnostic and statistical manual of mental disorders – fourth edition (DSM-IV) was used as the diagnostic criteria to include and exclude patients, anxiety disorders in this version of the DSM included post-traumatic stress disorder (PTSD) and obsessive-compulsive disorder (OCD), we do not comprehend why the diagnostic and statistical manual of mental disorders – fifth edition (DSM-5) was not used since it was published in 2013 and data were collected between 2017 and 2018 (American Psychiatric Association, 1994, 2013). Moreover, these patients with anxiety disorders were in use of benzodiazepines (BZD)? How many of them had PTSD or OCD? Third, Table 2 is misleading, mostly because it suppresses two of the duration parameter classes used in the Maudsley Staging Method (MSM), which are acute and subacute (Fekadu et al., 2009). For complete data analysis, all the classes should have been shown in Table 2 including the number of treatment failures. Fourth, why were chosen, out of all categories in the DSM-IV, only anxiety disorders to be reported, was because it was the only one to be statistically significant? Fifth, why most of the chosen patients have such a high body mass index (BMI) (mean = 29 and SD = 7.5)? The relation between treatment response and BMI was not made clear, as it was not shown if patients with a lower BMI responded equally to the ones with high BMI. It is important to make this clear, since there are pharmacokinetic differences in the bioavailability between patients with high rates of fat and ones with lower rates. In addition, there may be different drug effects, considering the different metabolic rates between these two groups. Lastly, six patients dropped out of the trial, but the reasons were not revealed, was it side effects, lack of efficacy?