New Tool Uses Depression Severity, Variability to Predict Suicide Risk

Batya Swift Yasgur, MA, LSW

March 05, 2019

A new assessment tool that detects severity and fluctuation of depressive symptoms accurately predicts the risk of suicidality in high-risk individuals, a new study suggests.

Investigators followed over 600 young adults with a mean age of 24 years who were at high risk for suicidal behavior because their parents had been diagnosed with mood disorders.

Parents and children were followed over a 12-year period and periodically evaluated through standard assessments.

The most accurate predictor of suicidal behavior was having severe depressive symptoms that fluctuated over time. 

The investigators combined this finding with other relevant factors, such as younger age, mood disorders, childhood abuse, and personal and family history of suicide attempts to create a Prediction Risk Score (PRS).

They found that having a score of 3 or more of these risk factors indicated a higher risk for suicidal behavior, with 87% sensitivity, which is far superior to currently available models.

"We recommend that clinicians pay particular attention in their assessment of depression to the severity of both current and past depression and the variability in these symptoms," lead author Nadine M. Melhem, PhD, associate professor of psychiatry, University of Pittsburgh School of Medicine, told Medscape Medical News.

"Our PRS is a valuable addition to predict suicide attempt in high-risk individuals and uses variables that are already collected as part of the medical history assessment in clinical settings," she said.

The study was published online February 27 in JAMA Psychiatry.

Lack of Predictability "Unacceptable"

"The prediction of suicidal behavior continues to be among the most challenging tasks in psychiatry," Melhem observed.

"A recent meta-analysis of the past 50 years of research showed that the prediction of suicidal ideation, attempt, and suicide deaths was only slightly better than chance, which is unacceptable for a life-threatening outcome like suicidal behavior," she said.

"Here, we focused on symptoms and their variability over time because, while psychiatric diagnoses are important predictors of suicidal behavior, diagnoses and stable or trait-like predictors are of limited value because the risk of suicidal behavior varies during the course of psychiatric illness," she reported.

The researchers "examined the trajectories of impulsivity, aggression, impulsive aggression, depression symptoms, irritability, and hopelessness in a longitudinal study of offspring of parents with mood disorders."

They examined whether changes in these measures over time could predict suicidal attempts as well as time to onset of the attempt, above and beyond any psychiatric diagnoses and other predictors.

Additionally, they computed a risk score based on their models and assessed its performance.

The study included 663 offspring of 318 parents (referred to as probands) with a lifetime history of mood disorders; over half had a lifetime history of an actual suicide attempt.

Recruitment of participants took place between July 15, 1997 and September 6, 2005, and participants were followed through January 21, 2014.

"Suicide attempt" in offspring was defined in both "broad" and "narrow" terms.

"Broad" included an actual attempt or a suicide-related behavior, while "narrow" included only actual attempts.

A 10-fold cross-validation model was used for statistical analysis; machine- learning regression techniques were used to determine a subset of predictors with the strongest effects.

Probands and offspring were interviewed at baseline, and then at annual follow-ups for a 12-year period using a variety of established scales.

Monitor Severity, Variability

The number of male and female offspring were approximately even (47.7% female), with a mean (SD) age of 23.8 (8.5) years; most participants (70.3%) were white.

Participants were followed for a median (range) of 8.1 (1 – 15.4) years.

Among the offspring, 71 (10.7%) had suicide attempts over the course of the study. Of these, 51 were first-time attempts (incidence rate 8.4%).

Among those who attempted suicide, the mean (SD) number of suicide attempts and actual attempts were 1.2 (0.6) and 1.3 (0.7), respectively.

The mean (SD) lethality (for actual attempts only) was 1.7 (2), "which corresponded to physical damage for which medical attention was needed," the investigators write.

The median time from the last assessment point to suicide attempt was 45 (1 – 126) weeks and 30 (4 – 126) weeks for actual attempt.

The researchers identified a two-class model for each of the factors they identified, and found that class 2 consistently showed higher mean scores and variability vs class 1 in measures of hopelessness, impulsivity, aggression, and irritability.

For depression, they identified a three-class model, in which class 3 showed the highest mean scores and variability (2.08 [0.75] vs 0.59 [0.42] vs –0.44 [0.28] (class 1); F 2,644 = 1216.7; P < .001; Cohen d class 3 vs 2 = 2.97; Cohen d class 3 vs 1 = 7.31; Cohen d class 2 vs 1 = 3.17).

Participants with suicide attempt were to be more likely than those without attempt to belong to class 3 depression symptoms, with higher mean and variability (16 [22.9%] vs 27 [4.7%];  <  .001; Cohen d = 0.72), the authors report.

They were also more likely to belong to class 2 for impulsivity, aggression, impulsive aggression, and irritability.

The only statistically significant trajectory that predicted increased risk for suicide attempt in the offspring turned out to be class 3 depression symptoms with higher mean and variability (model 1 odds ratio [OR], 6.53 [95% confidence interval [CI], 2.53 - 16.87; t = 3.88; P  <  .001]; model 2 OR, 3.39 [95% CI, 1.32 - 8.66; t = 2.55; P = .01).

Class 3 depression symptoms remained associated with an almost eightfold increased risk for suicide attempt (OR, 7.69; 95% CI, 2.37 - 24.90; t = 3.40; P  = .001) when the researchers included the trajectories for all measures, even after controlling for demographics and proband history of actual attempt.

In fact, class 3 depression symptoms were the only statistically significant trajectory to predict suicide attempt and remained so, even after the researchers controlled for additional clinical characteristics (OR, 4.72; 95% CI, 1.47 - 15.21; t = 2.60;  = .01).

"We recommend that clinicians monitor and treat depression symptoms over time to reduce their severity and fluctuation in high-risk young adults to reduce their risk for suicide attempt," Melhem said.

New Tool in the Toolbox

In addition to class 3 depression symptoms, the only ones that remained statistically significant in predicting the narrow and index attempt were:

  • Younger age (<30 years OR = 0.82; 95% CI, 0.74 - 0.9)

  • Lifetime history of unipolar and bipolar disorder (OR = 4.71; 95% CI, 1.63 - 13.58; and OR = 3.4; 95% CI, 0.96 - 12.04, respectively)

  • History of childhood abuse (OR = 2.98; 95% CI, 1.4 - 6.38)

  • Proband actual attempt (OR = 2.24; 95% CI, 1.06 - 4.75).

The researchers computed a risk score using these statistically significant predictors.

A risk score of 3 or higher resulted in the highest sensitivity (87.3%) and moderate specificity (63%; area under the curve = 0.80) for suicide attempt.

Although the positive predictive value was low, it increased as the prevalence of attempts increased.

"The PRS is not only a valuable addition to the physician's toolkit in predicting suicide risk, but it can also be done at little cost since the information is already being collected as part of standard evaluations," Melhem commented.

Greater Predictive Accuracy

Commenting on the study for Medscape Medical News, Beth Salcedo, MD, board president of the Anxiety and Depression Association of America, said that it "underscores the need for more and better treatments for depression," since we need to be "confident that the treatments we have cannot only get people better but also keep people better and control symptoms over time."

Salcedo, who is also the medical director of the Ross Center, a large outpatient practice with offices in Washington, DC and New York City, noted that it "has been long known that depression is a predictor of suicidal ideation and attempts, and the more severe the symptoms, the more concern one should have about that risk."

"It would be great if this new data could lead to a more accurate way of assessing an individual's risk, as this is something we are not at all able to do in current clinical practice," said Salcedo, who was not associated with the current study.

Melhem agreed, stating, "We are working on further improving the accuracy of this prediction model by adding objective biological markers."

The study was funded by the National Institute of Mental Health. Melhem reports receiving research support from the National Institute of Mental Health, Brain and Behavior Research Foundation, and the American Foundation for Suicide Prevention (AFSP). The other authors' disclosures are listed on the original paper. Salcedo has disclosed no relevant financial relationships.

JAMA Psychiatry. Published online February 27, 2019. Abstract

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