Are Suicide and Violent Crime Rates Inversely Related?

Suicide rates have increased across the United States — and in dozens of states by more than 30 percent, according to a new report from the U.S. Centers for Disease Control and Prevention based on public health data from 1999 to 2016.

Among suicide victims counted in 2015 in 27 states, 54 percent had no known mental health condition, researchers say in the June 8 report. For those who died, circumstances surrounding their suicide included relationship or job problems, the loss of a home, legal troubles and physical health issues. These factors played a role whether suicide victims had a diagnosed medical condition or not.

Overall, close to 45,000 Americans died by suicide in 2016. . . . By state or jurisdiction, the rates of suicide in the most recent period studied (2014 to 2016) ranged from 6.9 per 100,000 people in the District of Columbia to 29.2 per 100,000 for Montana.

From Science News citing D. Stone et al. "Vital Signs: Trends in state suicide rates — United States, 1999-2016 and circumstances contributing to suicide — 27 states, 2015." 67 Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report 634 (June 8, 2018).

What else was happening as suicide rates surged?

All across the United States crime rates, including violent crime rates, were plummeting.

Image from here.

My hypothesis, changes in suicide rates are inversely correlated with changes in violent crime rates, which would be fairly easy to confirm by comparing changes in suicide rate with changes in violent crime rates on a state by state basis in the same time period (e.g. from data here and here).

Why would this happen?

Lots of people who might otherwise commit suicide, when violent crime rates are high, instead engage in criminal behavior that creates a high risk that they will be killed. Joining a gang or robbing a bank at gunpoint are not all that different from playing Russian roulette psychologically.

Even if it isn't such a direct tradeoff, the risk factors that make someone a potential suicide victim and the risk factors that make someone a potential violent crime victim and the risk factors that make someone a potential violent crime perpetrator heavily overlap, and less death and incapacitation from violent crime makes these highest risk individuals more available to become suicide victims.

This could also explain why adolescent and young black men have below average suicide rates, even though younger black children have above average suicide rates.

Other Considerations

There is a direct intersection between suicide and homicide although it is a relative small part of the overall relationship:

Suicide decedents without known mental health conditions also had significantly higher odds of perpetrating homicide followed by suicide (aOR = 2.9, 95% CI = 2.2–3.8).

An alternative thought: Increases in suicide rate and opioid overdoses are correlated strongly in this time period. Could opioid overdoses reduce crime by taking high risk people out of the pool of potential criminals?




The study says this about suicide in people with no known mental health conditions:

Suicide decedents without known mental health conditions (11,039; 54.0%) were compared with those with known mental health conditions (9,407; 46.0%) for 27 states. Whereas decedents were predominantly male (76.8%) (Table 1) and non-Hispanic white (83.6%), those without known mental health conditions, relative to those with mental health conditions, were more likely to be male (83.6% versus 68.8%; odds ratio [OR] = 2.3, 95% CI = 2.2–2.5) and belong to a racial/ethnic minority (OR range = 1.2–2.0). 

Suicide decedents without known mental health conditions also had significantly higher odds of perpetrating homicide followed by suicide (aOR = 2.9, 95% CI = 2.2–3.8). Among decedents aged ≥18 years, 20.1% of those without known mental health conditions and 15.3% of those with mental health conditions had previously served in the U.S. military or were serving at the time of death. 

Whereas firearms were the most common method of suicide overall (48.5%), decedents without known mental health conditions were more likely to die by firearm (55.3%) and less likely to die by hanging/strangulation/suffocation (26.9%) or poisoning (10.4%) than were those with known mental health conditions (40.6%, 31.3%, and 19.8%, respectively). These differences remained significant in the adjusted models. 

Toxicology testing was less likely to be performed for decedents without known mental health conditions. Among those with toxicology results, decedents without known mental health conditions were less likely to test positive for any substance overall (aOR = 0.8, 95% CI = 0.7–0.8), including opioids (aOR = 0.90, 95% CI = 0.81–0.99), but were more likely to test positive for alcohol (aOR = 1.2, 95%, CI = 1.1–1.3). 

Information on circumstances surrounding suicide were available for all decedents with mental health conditions (9,407) and approximately 85% of those without known mental health conditions (9,357) in 27 states (Table 2). Persons without known mental health conditions were less likely to have any problematic substance use (aOR = 0.7, 95% CI = 0.7–0.8) than were persons with known mental health conditions. Whereas two thirds of decedents with known mental health conditions had a history of mental health or substance use treatment (67.2%), just over half (54.0%) were in treatment at the time of death. 

Decedents without known mental health conditions had a significantly higher likelihood of any relationship problem/loss (45.1%) than did those with known mental health conditions (39.6%), specifically intimate partner problems (30.2% versus 24.1%), arguments/conflicts (17.5% versus 13.6%), and perpetrating interpersonal violence in the past month (3.0% versus 1.4%). Decedents without known mental health conditions were also more likely than were those with known mental health conditions to have experienced any life stressors (50.5% versus 47.2%) such as recent criminal legal problems (10.7% versus 6.2%) or eviction/loss of home (4.3% versus 3.4%) and were more likely to have had a recent or impending (within the preceding or upcoming 2 weeks, respectively) crisis (a current or acute event thought to contribute to the suicide) (32.9% versus 26.0%). All of these differences remained significant in the adjusted models. Physical health problems and job/financial problems were commonly contributing stressors among both persons without mental health conditions (23.2% and 15.6%, respectively) and those with mental health conditions (21.4% and 16.8%, respectively). Similarly, among all persons with recent crises, intimate partner problems were the most common types and did not differ by group. 

Decedents without known mental health conditions had significantly lower odds of recent release from any institution (aOR = 0.5, 95% CI = 0.4–0.5). Among those recently released, decedents without known mental health conditions were significantly more likely than decedents with mental health conditions to have been released from a correctional facility (25.7% versus 8.7%), hospital (43.7% versus 33.0%), or other facility, such as an alcohol/substance use treatment facility (24.2% versus 11.6%). Among decedents with known mental health conditions who were recently released from an institution, 46.7% were released from psychiatric facilities. 

Decedents without known mental health conditions were significantly less likely to have a history of suicidal ideation (23.0%) or prior suicide attempts (10.3%) compared with those with known mental health conditions (40.8% and 29.4%, respectively). Suicide intent was disclosed by 22.4% and 24.5% of persons without and with known mental health conditions, respectively.