Validity of the depressive dimension extracted from principal component analysis of the PANSS in drug-free patients with schizophrenia

• Published in: Schizophrenia research Vol. 56; no. 1; pp. 121 - 127
• Main Authors: El Yazaji, Meriem, Battas, Omar, Agoub, Mohamed, Moussaoui, Driss, Gutknecht, Christel, Dalery, Jean, d'Amato, Thierry, Saoud, Mohamed
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-07-2002; Elsevier Science
• Subjects: Acute Disease; Adult; Biological and medical sciences; Depression; Depression - classification; Depression - diagnosis; Depression - psychology; Depression scales; Female; Humans; Male; Medical sciences; PANSS; Patient Admission; Principal Component Analysis; Psychiatric Status Rating Scales - statistics & numerical data; Psychology. Psychoanalysis. Psychiatry; Psychometrics; Psychometrics. Diagnostic aid systems; Psychopathology. Psychiatry; Reproducibility of Results; Schizophrenia; Schizophrenia - classification; Schizophrenia - diagnosis; Schizophrenic Psychology; Techniques and methods; Schizophrenia; Depression scales; Depression; PANSS; Mood disorder; Human; Factor analysis; Evaluation scale; Acute; Prediction; Psychometrics; Psychosis; Test validation; Symptomatology; Positive and Negative Syndrome Scale Kay et al; Comparative study; Principal component analysis
• ISSN: 0920-9964; 1573-2509
• DOI: 10.1016/S0920-9964(01)00247-X

Depressive symptoms frequently occur during the course of schizophrenia. This study explored the relationships between the schizophrenia symptomatology and three measures of depression.
Eighty-one drug-free inpatients with acute schizophrenia were assessed with the positive and negative syndrome scale (PANSS), the Calgary depression scale for schizophrenia (CDSS), and the Hamilton rating scale for depression (HAM-D). The depressive subscale of PANSS (PANSS-D) was also considered as a third scale for measuring depression.
A principal component analysis (PCA) of PANSS items identified five clinical dimensions of schizophrenia called ‘negative’, ‘positive’, ‘anxio-depressive’, ‘excitement’, and ‘disorganisation and others’. Our anxio-depressive dimension (PANSS-ad) was strictly identical with the PANSS-D. Scores on CDSS and HAM-D were highly inter-correlated and highly correlated with the PANSS-ad. Furthermore, while scores on CDSS were correlated only with this dimension, scores at HAM-D were also positively correlated with the negative dimension and negatively correlated with the excitement dimension.
In conclusion, our results suggest that PANSS evaluation itself may be sufficient to give a correct approximation of the depression in patients with schizophrenia. However, depression scales are of course needed to assess specifically depressive symptoms in patients with schizophrenia; hence, the CDSS could be a more specific instrument than HAM-D.