Homicide and suicide seem to both be extreme behavior and possibly ways of coping with similar stresses such as rejection, betrayal, loss. They are both types of murder.
There had been a lot of inconclusive research trying to examine the correlation between murder and suicide, until this study Correlating homicide and suicide 1, cited below, in 2005.
The findings show that globally there are weak correlations between murder and suicide, however there were significant differences between geographical regions. This study shows the relationship between homicide and suicide within a community.
Homicide and suicide are theorized as alternate and causal forms of violence.
Direction and strength of the relationship between homicide and suicide rates vary with geographic regions.
Homicide and suicide rates are positively correlated in European countries and inversely correlated in the Americas and Asia Pacific.
Cultural and socioeconomic differences may have contributed to the divergent geographic patterns. 1
From The Brains of Violent Males: The homicidal & suicidal brain Nicole Jackman:
Current research supports the notion that homicide and suicide are not unique behaviors characterized by distinctive brain anatomy and chemistry. It should be noted that homicide is the only crime that regularly results in the offenders taking their own life after committing the crime . Of the data collected on suicide victims and murderers, there are comparable deficiencies in the pre-frontal cortex and the serotonergic system. Mechanistically, the dysfunction of the prefrontal cortex in suicidal individuals and murderers is believed to be due to reduced levels of circulating serotonin ...
... In a study of violent prisoners, it was found that the offenders had significantly lower levels of serotonin in their brains. Research has shown that 95 percent of the brains of suicidal individuals show an altered serotonergic system, which is characterized by reduced serotonin activity. Decreases in pre-synaptic serotonin nerve terminal binding sites have been observed in the suicidal brain and there are more postsynaptic serotonin receptors in the prefrontal cortex of suicide victims, which suggests that the body is trying to compensate for low levels of serotonin.
What studies are there showing any possible correlations within the individual?
Is there a correlation between the propensity for someone to commit homicide and suicide?
1 Correlating homicide and suicide Corey B Bills and Guohua Li Int. J. Epidemiol. (August 2005) 34 (4): 837-845. doi: 10.1093/ije/dyi079
No anecdotal evidence please.