Negative symptoms in schizophrenia – the remarkable impact of inclusion definitions in clinical trials and their consequences

Negative symptoms of psychosis: A life course approach and implications for prevention and treatment

“…This concept is similar to cognitive reserve theory for dementia, which suggests that factors across the lifespan such as higher education, participation in mentally stimulating activities and complexity of occupation can increase an individual's protection against dementia (Harrison et al, ). Cognitive reserve theory has been mainly applied to dementia, although more recently the “reserve” concept has also been suggested for cognitive deficits in schizophrenia (de la Serna et al, ; Rabinowitz et al, ).…”

Primary and persistent negative symptoms: Concepts, assessments and neurobiological bases

“…Two definitions have been used (Kinon et al, 2006;Rabinowitz et al, 2013;Stauffer et al, 2012) to identify a population with clinically-relevant negative symptoms: prominent and predominant negative symptoms (Kinon et al, 2006;Rabinowitz et al, 2013;Stauffer et al, 2012). Criteria were based on the PANSS scores and identified different patient populations.…”

“…Prominent negative symptoms were defined as (1) Baseline score ≥ 4 (moderate) on at least three, or ≥ 5 (moderately severe) on at least two negative PANSS subscale items (Kinon et al, 2006;Stauffer et al, 2012;Rabinowitz et al, 2013). The definitions of predominant negative symptoms were more heterogeneous and included: (1) the same severity threshold for the PANSS negative subscale as for prominent negative symptoms, plus a PANSS positive score of less than 19 (Stauffer et al, 2012); (2) PANSS negative subscale score at least 6 points higher than the PANSS positive subscale score (Olie et al, 2006); (3) PANSS negative subscale score of at least 21 and at least 1 point greater than the PANSS positive subscale (Riedel et al, 2005) and (4) a common sense definition: PANSS negative subscale greater than the positive one (Rabinowitz et al, 2013).…”

“…The definitions of predominant negative symptoms were more heterogeneous and included: (1) the same severity threshold for the PANSS negative subscale as for prominent negative symptoms, plus a PANSS positive score of less than 19 (Stauffer et al, 2012); (2) PANSS negative subscale score at least 6 points higher than the PANSS positive subscale score (Olie et al, 2006); (3) PANSS negative subscale score of at least 21 and at least 1 point greater than the PANSS positive subscale (Riedel et al, 2005) and (4) a common sense definition: PANSS negative subscale greater than the positive one (Rabinowitz et al, 2013). Thus, the definition of the predominant negative symptoms is characterized by the reduced severity of the positive symptomatology with respect to the negative one.…”

Public–private partnerships to revitalize psychiatric drug discovery

“…[16]. It has, for instance, created a large database of schizophrenia clinical trial data contributed by industry (> 20,000 patients in > 25 countries) and analyzed by academia, with findings on the impact of operational criteria for negative symptom change that should prove very useful in designing future trials [17].…”