TY - JOUR
T1 - Paternal age related schizophrenia (PARS)
T2 - Latent subgroups detected by k-means clustering analysis
AU - Lee, Hyejoo
AU - Malaspina, Dolores
AU - Ahn, Hongshik
AU - Perrin, Mary
AU - Opler, Mark G.
AU - Kleinhaus, Karine
AU - Harlap, Susan
AU - Goetz, Raymond
AU - Antonius, Daniel
PY - 2011/5
Y1 - 2011/5
N2 - Paternal age related schizophrenia (PARS) has been proposed as a subgroup of schizophrenia with distinct etiology, pathophysiology and symptoms. This study uses a k-means clustering analysis approach to generate hypotheses about differences between PARS and other cases of schizophrenia. Methods: We studied PARS (operationally defined as not having any family history of schizophrenia among first and second-degree relatives and fathers' age at birth ≥ 35. years) in a series of schizophrenia cases recruited from a research unit. Data were available on demographic variables, symptoms (Positive and Negative Syndrome Scale; PANSS), cognitive tests (Wechsler Adult Intelligence Scale-Revised; WAIS-R) and olfaction (University of Pennsylvania Smell Identification Test; UPSIT). We conducted a series of k-means clustering analyses to identify clusters of cases containing high concentrations of PARS. Results: Two analyses generated clusters with high concentrations of PARS cases. The first analysis (N = 136; PARS = 34) revealed a cluster containing 83% PARS cases, in which the patients showed a significant discrepancy between verbal and performance intelligence. The mean paternal and maternal ages were 41 and 33, respectively. The second analysis (N = 123; PARS = 30) revealed a cluster containing 71% PARS cases, of which 93% were females; the mean age of onset of psychosis, at 17.2, was significantly early. Conclusions: These results strengthen the evidence that PARS cases differ from other patients with schizophrenia. Hypothesis-generating findings suggest that features of PARS may include a discrepancy between verbal and performance intelligence, and in females, an early age of onset. These findings provide a rationale for separating these phenotypes from others in future clinical, genetic and pathophysiologic studies of schizophrenia and in considering responses to treatment.
AB - Paternal age related schizophrenia (PARS) has been proposed as a subgroup of schizophrenia with distinct etiology, pathophysiology and symptoms. This study uses a k-means clustering analysis approach to generate hypotheses about differences between PARS and other cases of schizophrenia. Methods: We studied PARS (operationally defined as not having any family history of schizophrenia among first and second-degree relatives and fathers' age at birth ≥ 35. years) in a series of schizophrenia cases recruited from a research unit. Data were available on demographic variables, symptoms (Positive and Negative Syndrome Scale; PANSS), cognitive tests (Wechsler Adult Intelligence Scale-Revised; WAIS-R) and olfaction (University of Pennsylvania Smell Identification Test; UPSIT). We conducted a series of k-means clustering analyses to identify clusters of cases containing high concentrations of PARS. Results: Two analyses generated clusters with high concentrations of PARS cases. The first analysis (N = 136; PARS = 34) revealed a cluster containing 83% PARS cases, in which the patients showed a significant discrepancy between verbal and performance intelligence. The mean paternal and maternal ages were 41 and 33, respectively. The second analysis (N = 123; PARS = 30) revealed a cluster containing 71% PARS cases, of which 93% were females; the mean age of onset of psychosis, at 17.2, was significantly early. Conclusions: These results strengthen the evidence that PARS cases differ from other patients with schizophrenia. Hypothesis-generating findings suggest that features of PARS may include a discrepancy between verbal and performance intelligence, and in females, an early age of onset. These findings provide a rationale for separating these phenotypes from others in future clinical, genetic and pathophysiologic studies of schizophrenia and in considering responses to treatment.
KW - Cluster analysis
KW - K-Means clustering
KW - PARS
KW - Paternal age related schizophrenia
KW - Schizophrenia
UR - http://www.scopus.com/inward/record.url?scp=79955468233&partnerID=8YFLogxK
U2 - 10.1016/j.schres.2011.02.006
DO - 10.1016/j.schres.2011.02.006
M3 - Article
C2 - 21353765
AN - SCOPUS:79955468233
SN - 0920-9964
VL - 128
SP - 143
EP - 149
JO - Schizophrenia Research
JF - Schizophrenia Research
IS - 1-3
ER -