Classification trees distinguish suicide attempters in major psychiatric disorders: a model of clinical decision making.
OBJECTIVE
Determining risk for a suicide attempt in psychiatric patients requires assessment of multiple risk factors and knowledge of their relative importance. Classification and regression tree (CART) analysis generates decision trees that select the variables that perform best in identifying the group of interest and model clinical decision making. Hypothetical decision trees to identify recent and remote suicide attempters, weighted to increase sensitivity, were generated for psychiatric patients using correlates of past suicidal behavior.


METHODS
Correlates of past suicide attempts were identified in 408 patients with mood, schizophrenia spectrum, or personality disorders (DSM-IV). Correlated variables were entered into recursive partitioning statistical models to generate equally weighted and unequally weighted hypothetical decision trees for distinguishing recent (</= 30 days prior to study) and remote (> 250 days prior to study) suicide attempters from nonattempters. The study was conducted from December 1989 to November 1998.


RESULTS
In equally weighted trees, a recent past suicide attempt was best predicted by current suicidal ideation (sensitivity = 56%, specificity = 91%, positive predictive value = 69%), and no adequate model was found for remote attempts. In unequally weighted models, recent attempters were identified by suicidal ideation and comorbid borderline personality disorder (sensitivity = 73%, specificity = 80%, positive predictive value = 58%). Remote attempters were identified by lifetime aggression and current subjective depression (sensitivity = 89%, specificity = 36%, positive predictive value = 44%).


CONCLUSIONS
Current suicidal ideation is the best indicator of a recent suicide attempt in psychiatric patients. Indicators of a remote attempt are aggressive traits and current depression. Weighted decision trees can improve sensitivity and miss fewer attempters but with a cost in specificity.
Mann
J John
JJ
Department of Neuroscience, New York State Psychiatric Institute, New York 10032, USA. jjm@columbia.edu
Ellis
Steven P
SP
Waternaux
Christine M
CM
Liu
Xinhua
X
Oquendo
Maria A
MA
Malone
Kevin M
KM
Brodsky
Beth S
BS
Haas
Gretchen L
GL
Currier
Dianne
D
D000293:Adolescent; D000328:Adult; D000368:Aged; D000465:Algorithms; D003663:Decision Trees; D003937:Diagnosis, Differential; D039721:Diagnostic and Statistical Manual of Mental Disorders; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D019964:Mood Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D010554:Personality Disorders / Q000175:diagnosis / Q000453:epidemiology* / Q000523:psychology*; D011237:Predictive Value of Tests; D012307:Risk Factors; D012559:Schizophrenia / Q000175:diagnosis / Q000453:epidemiology*; D012565:Schizophrenic Psychology; D013406:Suicide, Attempted / Q000145:classification / Q000523:psychology / Q000706:statistics & numerical data