Negative symptoms in schizophrenia: a study in a large clinical sample of patients using a novel automated method

Abstract

ObjectivesTo identify negative symptoms in the clinical records of a large sample of patients with schizophrenia using natural language processing and assess their relationship with clinical outcomes.DesignObservational study using an anonymised electronic health record case register.SettingSouth London and Maudsley NHS Trust (SLaM), a large provider of inpatient and community mental healthcare in the UK.Participants7678 patients with schizophrenia receiving care during 2011.Main outcome measuresHospital admission, readmission and duration of admission.Results10 different negative symptoms were ascertained with precision statistics above 0.80. 41% of patients had 2 or more negative symptoms. Negative symptoms were associated with younger age, male gender and single marital status, and with increased likelihood of hospital admission (OR 1.24, 95% CI 1.10 to 1.39), longer duration of admission (β-coefficient 20.5 days, 7.6–33.5), and increased likelihood of readmission following discharge (OR 1.58, 1.28 to 1.95).ConclusionsNegative symptoms were common and associated with adverse clinical outcomes, consistent with evidence that these symptoms account for much of the disability associated with schizophrenia. Natural language processing provides a means of conducting research in large representative samples of patients, using data recorded during routine clinical practice.

Healthcare resource use in schizophrenia, EuroSC findings

“…In terms of hospitalisations, which are likely to be the most expensive of the healthcare resources investigated, the average needs in patients with severe negative symptoms (HS4) were lower only than in those with extremely severe symptoms (HS8). These results suggest that effective targeting of negative symptoms is likely not only to improve quality of life and social interaction in patients with schizophrenia, as described above, but it may also substantially lower the burden schizophrenia poses on healthcare systems, especially given that negative symptoms are rather common [41,42]. …”

“…We studied the EuroSC cohort, a representative sample of schizophrenia patients from three European countries, which has been extensively used in prior research on this debilitating disease [15–25] Within this cohort, up to a third of patients were in HS2 or HS4 and experienced predominantly negative symptoms that were classed as moderate or severe, in line with earlier studies suggesting that negative symptoms of schizophrenia are indeed very common. In previous reports, 41% of patients experienced two or more negative symptoms [41], while as many as 58% had at least one negative symptom [42]. The impact of negative symptoms on overall functional impairment is substantial and no specific treatment can be considered particularly effective against these symptoms, according to the evidence base summarised in a recent review [43].…”

What proportion of patients with psychosis is willing to take part in research? A mental health electronic case register analysis

“…Data for this study were obtained from these sources of clinical data using the Clinical Record Interactive Search tool (CRIS). CRIS is a bespoke database search and assembly tool which has supported a range of studies [20][21][22][23][24][25] using clinical data from the SLaM BRC Case Register.…”

Data science for mental health: a UK perspective on a global challenge

“…Recent enhancements include the development of natural language processing applications to derive structured information from the text fields present in the electronic mental health record. These include recorded diagnoses, cognitive test scores, pharmacotherapy and symptom profiles [38][39][40][41][42] .…”