The tragedy of maternal filicide, or child murder by mothers, has occurred throughout history and throughout the world. This review of the research literature sought to identify common predictors in the general population as well as in correctional and psychiatric samples. Further research is needed to improve identification of children and mothers at risk. Infanticide laws are discussed. Suggestions for prevention are made based on the current literature and the authors' experiences.
When a young child is murdered, the most frequent perpetrator is a victim's parent or stepparent (1). Rates of infanticide parallel suicide rates rather than murder rates (2). The risk of being a homicide victim is highest during the first year of life (3-5). Though the US has the highest rates of child homicide (8.0/100,000 for infants, 2.5/100,000 for preschool-age children, and 1.5/100,000 for school-age children), the problem of child homicide transcends national boundaries (6). These rates of child murder are probably underestimates, due to inaccurate coroner rulings and some bodies never being discovered (4,7,8).
Maternal filicide is defined as child murder by the mother. Infanticide is child murder in the first year of life. The term neonaticide was coined by Resnick (9) to describe murder of an infant within the first 24 hours of life. Almost all neonaticides are committed by mothers. Neonaticidal mothers are often young, unmarried women with unwanted pregnancies who receive no prenatal care. For a detailed analysis of the neonaticide literature and a discussion of neonaticide prevention, the reader is referred to our recent review (10).
Resnick's review of the world psychiatric literature on maternal filicide (11) found filicidal mothers to have frequent depression, psychosis, prior mental health treatment, and suicidal thoughts. Maternal filicide perpetrators have five major motives: a) in an altruistic filicide, a mother kills her child out of love; she believes death to be in the child's best interest (for example, a suicidal mother may not wish to leave her motherless child to face an intolerable world; or a psychotic mother may believe that she is saving her child from a fate worse than death); b) in an acutely psychotic filicide, a psychotic or delirious mother kills her child without any comprehensible motive (for example, a mother may follow command hallucinations to kill); c) when fatal maltreatment filicide occurs, death is usually not the anticipated outcome; it results from cumulative child abuse, neglect, or Munchausen syndrome by proxy; d) in an unwanted child filicide, amother thinks of her child as a hindrance; e) the most rare, spouse revenge filicide occurs when a mother kills her child specifically to emotionally harm that child's father.
In developing countries, the preference for male infants may lead to sex-selective killings (12,13). Cultural and legal differences across countries may affect research findings. For example, one country's correctional sample may be similar to another country's psychiatric sample, depending on the laws and attitudes toward prosecution.
The purposes of this paper are to summarize recent research findings about maternal filicide, and to consider potential strategies for prevention. The authors completed database searches for peer-reviewed articles in English regarding maternal filicide over the past quarter century. Studies were separated by population type, as in our previous analysis (14), because studies in the general population differ from those in psychiatric or correctional populations. Maternal filicide-suicide (a mother kills both her child and herself) was considered independently.
Countries represented in the English literature filicide search were Australia, Austria, Brazil, Canada, Finland, France, Hong Kong, Japan, Ireland, New Zealand, Sweden, Turkey, the United Kingdom, and the United States. In addition to studies of mothers who have committed filicide (3,4,15-55), several studies have investigated the prevalence of filicidal thoughts in various populations.
An American macro-level study of infanticide (victims in the first year of life) found increased rates with economic stress (24). Although England and Wales have Infanticide Acts, and Scotland does not, the countries experience similar rates of infanticide (3,38). Maternal infanticide studies in the general population (20,38,44,45) found a predominance of unemployed mothers in their early 20s. Many cases occurred in the context of child abuse (4), though some mothers had associated suicide attempts. Often they experienced psychiatric disorders (36 to 72%) (44,45). In Japan, the infant victims frequently had physical anomalies.
The mothers were often poor, socially isolated, full-time caregivers, who were victims of domestic violence or had other relationship problems. Disadvantaged socioeconomic backgrounds and primary responsibility for the children were common. Persistent crying or child factors were sometimes precipitants for the filicide. Some mothers had previously abused the child, while others were mentally ill and devoted to their child (41). Neglectful or abusive mothers were often substance abusers. Many of the perpetrators had psychosis, depression, or suicidality (15,16,18,20,28,40-43,45,48,51,52).
In the correctional population, filicidal mothers were frequently unmarried, unemployed abuse victims, who had limited education and social support (29-33,46-47,53,54). Some had decreased intellect, and a few considered the child victim to be abnormal. Several correctional studies noted frequent depression, psychosis, substance abuse, suicidality, and prior mental health care (33,46,47,53,54). Multiple stressors (economic, social, abuse history, partner relationship problems), primary caregiver status, and difficulty caring for the child were frequent.
The filicidal mothers in psychiatric samples had frequently experienced psychosis, depression, suicidality, and prior mental health care (18,19,22,25-27,34-37,39,49,50,55). Their mean age was in their late 20s (18,19,22,25,34-36). Some were diagnosed with personality disorders and some had low intelligence. Significant life stresses were often noted. Our recent study of mothers found not guilty by reason of insanity in two U.S. states found that the perpetrators were often depressed and frequently experienced auditory hallucinations, some of a command type. Over one third of the homicides occurred during pregnancy or the postpartum year. Almost all the mothers had altruistic or acutely psychotic motives (22). A small New Zealand study that interviewed the mothers after their filicides found that psychotic mothers who had committed filicide often killed suddenly without much planning, whereas depressed mothers had contemplated killing their children for days to weeks prior to their crimes (49).
A significant proportion (16-29%) of filicides end in completed suicide by the mother (56). Many other mothers make non-fatal suicide attempts in association with their filicides. When mothers of young children commit suicide, about 5% also kill at least one of their children (57,58).
Filicide-suicides have much in common with filicides committed by severely mentally ill mothers (15). Most frequently, these mothers have altruistic motives (15,23). Similar to results of other studies (15,20,48), our recent American study found that maternal filicide-suicide perpetrators killed older children more often than infants (mean age of children killed was 6 years old). The mothers often had evidence of depression or psychosis (23). These mothers often take the lives of all their young children.
A relatively high incidence of filicidal thoughts has been found in mentally ill women. Jennings et al's (59) study of depressed mothers with children under age 3 found that 41% had thoughts of harming a child, compared with 7% of mothers in the control group. A pediatric study of mothers in the general population found that 70% of mothers with colicky infants experienced explicit aggressive thoughts toward their infants, and over a quarter (26%) of them had infanticidal thoughts during colic episodes (60). An Indian study (61) of hospitalized severely mentally ill postpartum women found that 43% had infanticidal ideation. Thirty-six percent of these women engaged in some type of infanticidal behavior. Their behavior was associated with negative maternal reaction to separation, psychotic beliefs about the infant, and female sex of the infant.
Our recent survey of psychiatrists at two American academic institutions found that many psychiatrists do not specifically ask their patients who are mothers about thoughts of harming their children, but rather they inquire generally about homicidal thoughts (62). The surveyed psychiatrists frequently underestimated the prevalence of depressed mothers who have thoughts of harming their children.
Infanticide laws often reduce the penalty for mothers who kill their children up to one year of age, based on the principle that a woman who commits infanticide does so because "the balance of her mind is disturbed by reason of her not having fully recovered from the effect of giving birth to the child" (41). The British Infanticide Act of 1922 (amended in 1938) allows mothers to be charged with manslaughter rather than murder if they are suffering from a mental disturbance. The law was originally based on the outdated concept of lactational insanity, but the public's desire to excuse sympathetic women caused reluctance to alter the law after lactational insanity was discredited. Women convicted of infanticide often receive probation and referral to mental health treatment rather than incarceration (41).
Approximately two dozen countries currently have infanticide laws (Australia, Austria, Brazil, Canada, Colombia, Finland, Germany, Greece, Hong Kong, India, Italy, Japan, Korea, New Zealand, Norway, Philippines, Sweden, Switzerland, Turkey and the United Kingdom (12,19,21,41,63). The majority of nations that have infanticide laws have followed the British precedent and decrease the penalty for mothers killing children under one year old. However, the legal definition of infanticide varies among countries. The murder of children up to age ten is included in New Zealand (21).
In practice, however, women convicted of infanticide in England sometimes do not have significant mental illness as technically required by the law (64). Opponents of infanticide laws point out that fathers are granted far less leniency. A father who is equally psychotically depressed as a mother, who kills his 10-month-old child in an altruistic psychotic belief with an associated suicide attempt, should not be treated differently than a similarly situated mother. Some feminists criticize the infanticide laws for "pathologizing childbirth". They believe that making this exception for women denies them the same capacity for self-governance attributed to men (65). Furthermore, it is illogical that a mother who in the throes of postpartum psychosis killed her newborn and her two-year-old should be charged with infanticide/manslaughter for the homicide of the newborn and murder for the homicide of the two-yearold. If the U.S. had an infanticide law, Andrea Yates would not have qualified, because in addition to her infant she killed her four older children. An acutely psychotic mother who killed her 13 month old child would not qualify for the infanticide law in England though a mother who battered her 11 month old child might.
Psychiatrists should assess filicide risk in a systematic way, as they do for suicide. First they must entertain the possibility of maternal filicide. Psychiatrists should intervene to prevent potential filicides in which maternal mental illness plays a role. Mothers who have altruistic or acutely psychotic motives for filicide may be psychotic, depressed, manic, or delirious. Some mothers who come to psychiatric attention because of severe mental illnesses, personality disorders, or substance use disorders may be abusing or neglecting their children. Psychiatrists may ask about childrearing practices, parenting problems, and feelings of being overwhelmed. Strategies for prevention must be tailored to the different motivations of mothers who commit filicide.
Depressed mothers who have the potential to kill in extended suicides should be identified early. Mothers contemplating suicide should be asked directly about the fate of their children if they were to take their own life. Some will say their husband is quite able to look after them and others will volunteer that they would take their children to heaven with them. Thoughts or fears of harming their children should be queried. Threats must be taken seriously. A lesser threshold for hospitalization should be considered for mentally ill mothers of young children due to the possibility of multiple deaths from a filicide-suicide. Factors which potentially merit psychiatric hospitalization include maternal fears of harming their child, delusions of their child's suffering, improbable concerns about their child's health, and hostility toward a despised partner's favorite child (66).
Psychotic mothers who fear that their children may suffer a fate worse than death due to persecutory delusions should either be hospitalized or separated from their children. These mothers may be reluctant to share their delusional ideas. Delusions may sometimes be elicited through a sympathetic exploration of their concerns for the safety of their children. In some cases, the only evidence of concern is frequent checking by the mother on the health and safety of her children. Though psychotic mothers may have less warning about filicide, psychiatrists can ask about hallucinations or delusional thoughts regarding the children. Among Indian mothers with postpartum severe mental illness, a recent study found that mothers with delusions about their infant engaged in more abuse (67).
Early screening and identification of mental illness both antenatally and postnatally is important. The Edinburgh Postnatal Depression Scale (68,69) is a validated tool that can be easily administered both in pregnancy and the postpartum. Up to 4% of mothers with untreated postpartum psychosis will commit infanticide (70). Because hospital length of stay after delivery is shorter now, many cases of postpartum psychosis could be undetected in the community. Therefore, community education is important. Support services for mothers and accessible psychiatric services for at-risk populations are needed.
More filicides occur due to fatal maltreatment than because of maternal psychiatric illness. Many cases of fatal maltreatment filicide never come to psychiatric attention. Mothers may kill their children who fail to respond to demands such as to stop crying (15). Mothers who batter their children to death are likely to have abused their children more than once before (15,25). Early intervention to protect these children is more likely to fall to child protective agencies than to psychiatrists. All 50 states in the U.S. have mandatory reporting laws for professionals who suspect child abuse. Parenting classes, emotional support, and emergency numbers to call when mothers are overwhelmed can be helpful in preventing fatal maltreatment filicides. Maternal substance abuse must also be treated. Child protective agencies must remove children who are at risk of serious abuse. Mothers who are diagnosed with Munchausen syndrome should be evaluated to see if they have engaged in Munchausen syndrome by proxy behaviors. Child protective agencies should be receptive to accepting children into their care who are unwanted, even if no abuse or neglect has yet occurred.
Spouse revenge filicide is difficult to prevent, because there is usually little warning. This behavior most often occurs after learning of spousal infidelity or in the course of child custody disputes. Sometimes a mother is so convinced that her child will be sexually abused if permanent custody is awarded to her ex-husband that she decides the child is better off in heaven. Evaluators of child custody disputes should be alert for this potential.
Children under age 5 may have limited contacts outside of their household and have difficulty speaking out to others, while older children often attend school and can thus reveal child abuse. In the U.S., child homicide rates peak in winter for young children under age 2, and in the summer for older children (ages 5-14) (71). Infant and child factors such as colic (60) or autism (72) may increase risk. This suggests a potential role for pediatricians in prevention as well.
A mother's motive for filicide may be altruistic, acutely psychotic, or due to fatal maltreatment, unwanted child, or spouse revenge. In addition, many mothers who do not attempt filicide experience thoughts of harming their child. Maternal filicide motives provide a framework for approaching filicide prevention. Suicidality, psychosis and depression elevate risk, as does a history of child abuse. Mentally ill filicidal mothers have very different risk profiles than mothers who fatally batter their children. Prevention is difficult, because many risk factors, such as maternal depression and social disadvantage, are common among non-filicidal mothers.