title: CSF biomarkers in suicide attempters--a principal component analysis.
abstract: OBJECTIVE
  The objective of the present study was to identify biological patterns (factors) among 20 cerebrospinal fluid (CSF) biomarkers in suicide attempters and subsequently analyse their association with suicidal behaviour.
  
  
  METHODS
  We measured kynurenic acid, orexin, homovanillic acid (HVA), 5-hydroxyindoleacetic acid (5-HIAA), 3-methoxy-4-hydroxyphenylglycol, chemokines, matrix metalloproteases and cytokines in the CSF of 124 drug-free suicide attempters. Patients were evaluated for suicidality and psychiatric symptoms using well-defined psychiatric rating scales and followed-up regarding future suicide. We used principal component analysis to identify factors among the biological substances.
  
  
  RESULTS
  Four factors were extracted from the 20 biomarkers, explaining 52.4% of the total variance. Factors 1 and 2 were characterized by high loadings of chemokines and cytokines respectively. They were both associated with severe depressive symptoms. Factor 2 was also associated with a high suicidal intent. Factor 4 was characterized by strong loadings of the monoamine metabolites 5-HIAA and HVA, as well as orexin and interleukin-6. High scores on this factor were found in patients who performed a violent suicide attempt and in patients who subsequently completed suicide.
  
  
  CONCLUSIONS
  Our results suggest that specific combinations of CSF biomarkers may discriminate between types of suicidal behaviour and indicate increased risk for future suicide.
authors.affiliation: Department of Clinical Sciences, Section of Psychiatry, Psychoimmunology Unit, Lund University Hospital, Kioskgatan 19, Lund, Sweden. Daniel.Lindqvist@med.lu.se
authors.forename: D
authors.initials: D
authors.lastname: Lindqvist
authors.forename: S
authors.initials: S
authors.lastname: Janelidze
authors.forename: S
authors.initials: S
authors.lastname: Erhardt
authors.forename: L
authors.initials: L
authors.lastname: Träskman-Bendz
authors.forename: G
authors.initials: G
authors.lastname: Engström
authors.forename: L
authors.initials: L
authors.lastname: Brundin
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000134:cerebrospinal fluid*; D018925:Chemokines / Q000134:cerebrospinal fluid; D016207:Cytokines / Q000134:cerebrospinal fluid; D005260:Female; D006719:Homovanillic Acid / Q000134:cerebrospinal fluid; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000134:cerebrospinal fluid; D047908:Intracellular Signaling Peptides and Proteins / Q000134:cerebrospinal fluid; D007736:Kynurenic Acid / Q000134:cerebrospinal fluid; D008297:Male; D020782:Matrix Metalloproteinases / Q000134:cerebrospinal fluid; D008734:Methoxyhydroxyphenylglycol / Q000134:cerebrospinal fluid; D009479:Neuropeptides / Q000134:cerebrospinal fluid; D000068797:Orexins; D025341:Principal Component Analysis; D013406:Suicide, Attempted
chemical_list: D015415:Biomarkers; D018925:Chemokines; D016207:Cytokines; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins; D008734:Methoxyhydroxyphenylglycol; D006897:Hydroxyindoleacetic Acid; D020782:Matrix Metalloproteinases; D007736:Kynurenic Acid; D006719:Homovanillic Acid