Up until now psychologists made predictions about the probability that a patient would attempt suicide based on a history of past suicide attempts, what the patient said regarding his present intent to commit suicide and what the psychologist believed based on interviewing the patient. Of these three factors, psychologists have relied most on what the patient self-reports about his intent. Yet, according to Harvard Professor of Psychology Matthew K. Nock this subjective method of predicting the likelihood a future suicide attempt is scarcely better than chance. That’s because patients who seriously intend to die by suicide are likely to conceal or misrepresent their intent to do so.
Because of this Dr. Nock was motivated to develop objective, computerized tests to gauge a patient’s propensity to attempt suicide in the near future. Working with Christine Cha, a doctoral student in psychology at Harvard, Dr. Nock came up with two objective tests which give good insight into this propensity and which can be administered within minutes on a computer. They reported their results in two separate articles, one in the July 2010 issue of the Journal of Abnormal Psychology and the other in Psychological Science.
The first test measures the strength of a patient’s attention to suicide-related stimuli. It’s a variation on the old Stroop test which measured a person’s ability to control and direct his attention. Since people can more easily recognize words than colors, the Stroop test will sometimes print a color word (say blue) in a matching color (blue) and sometimes in a conflicting color (say green). The computerized Stroop test gives a person a limited amount of time to correctly identify a series of color, some of which are printed in mismatched color words. This tells us if a part of his brain dedicated to sorting out attentional conflicts (the anterior cingulate cortex) is functioning properly.
In Dr. Nock’s version patients are given a limited amount of time to identify the color of words on a computer screen, some of which are suicide-related and some not. When he tried the Suicide Stroop test on 124 patients in a psychiatric emergency department he fared better in predicting the likelihood of an attempt within the next months than using traditional subjective measures.
The second test measures the strength of a patient’s unconscious association with suicide. It is a variation on the Implicit Association test developed by Harvard psychologist Mahzarin R. Banaji to detect hidden bias against people of different race, gender, age, economic status and the like. In Dr. Banaji’s test the subject would be shown word pairs to react to and their reaction time to the word pairs would be measured in milliseconds. Racial bias could be shown by a subject reacting faster to a pairing of an African American name than a Caucasian name with words suggesting criminal activity. The test works by reaching automatic mental associations beneath the level of consciousness.
In Dr. Nock’s modified version, he measured the reaction time of 157 patients to word pairs in which “self” was either linked to “life” or to “death/suicide.” When a patient consistently responded more rapidly to “death/suicide” than “life,” it was assumed he had a strong unconscious association with suicide. Dr. Nock and his associate found that within six months following test administration the patients who had a strong unconscious association with “death/suicide” on the modified Implicit Association test were six times more likely to attempt suicide than those holding a strong association between “self” and “life.”
Dr. Nock is to be credited for coming up with a new computerized test tool to help psychiatrists make a rapid and accurate risk assessment of the likelihood that an emergency psychiatric patient will attempt suicide. This assessment can help guide treatment and increase the odds of preventing suicides, especially in patients who profess they are not serious about committing suicide when they really are.
In recent times psychiatrists have begun moving away from Lithium and toward anti-convulsant drugs for long term stabilization of mood in patients with bipolar disorder. Anti-convulsants are drugs which were initially designed and FDA approved to prevent seizures in persons with epilepsy. Although anti-convulsants appear to work as a mood stabilizer for bipolar patients, questions have been raised about their safety, because some studies showed they increased the probability of suicide in the patients who take them. In December 2008 the FDA required all manufacturers of anti-convulsants to insert a warning about increased risk of suicide in the box without specifying the relative risks of particular brands. This move by the FDA was precipitated by its analysis of 199 clinical trials of 11 anti-epileptic drugs which showed that patients receiving anti-epileptic drugs had almost twice the risk of suicidal behavior or thoughts compared to patients receiving a placebo.