The diagnostic criteria for postpartum depression (PPD) are the
same as that for major depression, except that to distinguish PPD
from the baby (maternity) blues, the symptoms must be present past
the second week postpartum.
Predictors of Postpartum Depression
While not all causes of PPD are known, several factors have been
identified. Beck (2001) has conducted a meta-analysis of predictors
of PPD. She found that the following 13 factors were significant
predictors of PPD (effect size in parentheses -- larger values
indicate larger effects):
1. Prenatal depression, i.e., during pregnancy (.44 to .46)
2. Low self esteem (.45 to.47)
3. Childcare stress (.45 to .46)
4. Prenatal anxiety (.41 to .45)
5. Life stress (.38 to .40)
6. Low social support (.36 to .41)
7. Poor marital relationship (.38 to .39)
8. History of previous depression (.38 to.39)
9. Infant temperament problems/colic (.33 to .34)
10. Maternity blues (.25 to .31)
11. Single parent (.21 to .35)
12. Low socioeconomic status (.19 to .22)
13. Unplanned/unwanted pregnancy (.14 to .17)
These factors are known to correlate with PPD.
That means that, e.g., high levels of childcare stress are associated
PPD levels, and low levels of childcare stress are associated
with low levels of PPD. Some factors, like lack of social support,
known to cause postpartum depression. (The strong association
of PPD with lack of social support has been confirmed by over 60
see, e.g, the meta-analyses of Beck 1996a, and O’Hara and
Swain 1996. The causal role of lack of social support in PPD
is strongly suggested by, e.g., O'Hara 1985, Field et al. 1985;
Gotlib et al. 1991.)
Although profound hormonal changes after childbirth are often
claimed to cause PPD, there is little evidence that variation in
pregnancy hormone levels is correlated with variation in PPD levels:
Studies that have examined pregnancy hormone levels and PPD have
usually failed to find a relationship (see, e.g., Harris 1994;
O'Hara 1995). Further, fathers, who are not undergoing profound
hormonal changes, suffer PPD at relatively high rates. Finally,
all mothers experience these hormonal changes, yet only about 10-15%
suffer PPD. This does not mean, however, that hormones do not play
a role in PPD. Block et al (2000), for example, found that, in
women with a history of PPD , a hormone treatment simulating pregnancy
and parturition caused these women to suffer mood symptoms. The
same treatment, however, did not cause mood symptoms in women with
no history of PPD. One interpretation of these results is that
there is a subgroup of women who are vulnerable to hormone changes
during pregnancy. Another interpretation is that simulating a pregnancy
will trigger PPD in women who are vulnerable to PPD for any of
the reasons indicated by Beck's meta-analysis (summarized above).
Profound lifestyle changes brought about by caring for the infant
are also frequently claimed to cause PPD, but, again, there is
little evidence for this hypothesis. Mothers who have had several
previous children without suffering PPD can nonetheless suffer
it with their latest child. Plus, most women experience profound
lifestyle changes with their first pregnancy, yet most do not suffer
In severe cases, postpartum psychosis (also known as puerperal
psychosis) can develop, characterized by hallucinations and delusions.
This happens in about 0.1 - 0.2% of all women after having given
birth. In some cases, postpartum psychosis can develop independent
of postpartum depression.
Sometimes a preexisting mental illness can be brought to the forefront
through a postpartum depression.
An evolutionary psychological hypothesis for postpartum depression
Summary: Mothers with inadequate social support, an unhealthy child,
a lack of resources (e.g., financial problems in contemporary
societies), or other costly and stressful circumstances, have
negative reactions towards the baby because these mothers would
not have been able to successfully raise the child in ancestral-type
Evolutionary approaches to parental care (e.g., Trivers 1972)
suggest that parents (human and non-human) will not automatically
invest in all offspring, and will reduce or eliminate investment
in their offspring when the costs outweigh the benefits. Reduced
care, abandonment, and killing of offspring have been documented
in a wide range of species. In many bird species, for example,
both pre- and post-hatching abandonment of broods is common (e.g.,
Ackerman et al. 2003; Cezilly 1993; Gendron and Clark 2000).
Human infants require an extraordinary degree of
parental care. Lack of support from fathers and/or other family
member will increase
the costs born by mothers, whereas infant health problems will
reduce the evolutionary benefits to be gained. If ancestral mothers
did not receive enough support from fathers or other family members,
they may not have been able to "afford" raising the new
infant without harming any existing children, or damaging their
own health (nursing depletes mothers' nutritional stores, placing
the health of poorly nourished women in jeopardy).
For mothers suffering inadequate social support or other costly
and stressful circumstances, negative emotions directed towards
a new infant could serve an important evolved function by causing
the mother to reduce her investment in the infant, thereby reducing
Numerous studies support the correlation between
postpartum depression and lack of social support or other childcare
with postpartum depression also reduce their investment in their
new offspring. They commonly have thoughts of harming their children,
exhibit fewer positive emotions and more negative emotions toward
them, are less responsive and less sensitive to infant cues, less
emotionally available, have a less successful maternal role attainment,
and have infants that are less securely attached (Beck 1995, 1996b;
Cohn et al. 1990, 1991; Field et al. 1985; Fowles 1996; Hoffman
and Drotar 1991; Jennings et al. 1999; Murray 1991; Murray and
Cooper 1996). In other words, most mothers with PPD are suffering
some kind of cost, like inadequate social support, and consequently
are mothering less. PPD may be an adaptation that, via negative
emotions, informs mothers that they cannot "afford" the
new baby and that motivates them to reduce or eliminate investment
in offspring. It may also help them negotiate greater levels of
investment from others.
If this view is correct (and it is far from proven), mothers with
PPD do not have a mental illness, they need more social support,
more resources, etc. Treatment for PPD should therefore focus on
helping mothers get what they need. For more on this hypothesis,
see Hagen 1999 and Hagen and Barrett, n.d..
Andrea Yates Case
After the National Organization for Women (NOW) insisted that Andrea
Yates had postpartum depression, the Individualist Feminists
of Ifeminist.com pointed out that postpartum depression is quite
common and most sufferers do not murder their children. In fact,
Yates suffered from postpartum psychosis. After Ifeminist.com
pointed out that this stigmatized a large number of mothers and
made them less likely to seek professional help, NOW removed
their claims from their official website. Some believe that Yates'
fundamentalist church bears some responsibility for the murder,
as the church allegedly urged her to ignore her psychiatrist's
orders. Yates methodically drowned her children in a bathtub
in her Clear Lake City, Houston, Texas house on June 20, 2001.
Ackerman, J. T., Eadie, J. M., Yarris, G. S., Loughman, D. L., & Mclandress
R. M. (2003) Cues for investment: nest desertion in response to
partial clutch depredation in dabbling ducks. Animal Behaviour,
Beck, C.T. The effects of postpartum depression
on maternal-infant interaction: a meta-analysis. Nursing Research
Beck, C.T. A meta-analysis of predictions of postpartam
depression. Nursing Research 45:297–303, 1996a.
Beck, C.T. A meta-analysis of the relationship
between postpartum depression and infant temperament. Nursing
Bect, C.T. (2001) Predictors of Postpartum Depression: An Update.
Nursing Research, 50, 275-285.
Cezilly, F. (1993) Nest desertion in the greater flamingo, Phoenicopterus
ruber roseus. Animal Behaviour, 45, 1038-1040.
Cohn, J.F., Campbell, S.B., Matias, R., and Hopkins,
J. Face-to-face interactions of postpartum depressed and nondepressed
pairs at 2 months. Developmental Psychology 26:15–23, 1990.
Cohn, J.F., Campbell, S.B., and Ross, S. Infant
response in the still-face paradigm at 6 months predicts avoidant
attachment at 12 months. Special Issue: Attachment and developmental
Development and Psychopathology 3:367–376, 1991.
Field, T., Sandburg, S., Garcia, R., Vega-Lahr,
N., Goldstein, S., and Guy, L. Pregnancy problems, postpartum
early mother-infant interactions. Developmental Psychology 21:1152– 1156,
Fowles, E.R. Relationships among prenatal maternal
attachment, presence of postnatal depressive symptoms, and maternal
attainment. Journal of the Society of Pediatric Nurses 1:75–82,
Gendron, M. & Clark, R. G. (2000) Factors affecting brood
abandonment in gadwalls (Anas strepera). Canadian Journal of Zoology,
Gotlib, I.H., Whiffen, V.E., Wallace, P.M., and
Mount, J.H. Prospective investigation of postpartum depression:
factors involved in onset
and recovery. Journal of Abnormal Psychology 100:122– 132,
Harris, B. Biological and hormonal aspects of postpartum
depressed mood: working towards strategies for prophylaxis and
Special Issue: Depression. British Journal of Psychiatry 164:288–292,
Hoffman, Y., and Drotar, D. The impact of postpartum
depressed mood on mother-infant interaction: like mother like
Mental Health Journal 12:65–80, 1991.
Jennings, K.D., Ross, S., Popper, S., and Elmore, M. Thoughts
of harming infants in depressed and nondepressed mothers. Journal
of Affective Disorders, 1999.
Murray, L. Intersubjectivity, object relations
theory, and empirical evidence from mother-infant interactions.
Special Issue: The
effects of relationships on relationships. Infant Mental Health
Murray, L., and Cooper, P.J. The impact of postpartum
depression on child development. International Review of Psychiatry
O’Hara, M.W. Depression and marital adjustment during pregnancy
and after delivery. American Journal of Family Therapy 13:49–55,
O’Hara, M.W. Postpartum Depression: Causes
and Consequences. New York: Springer-Verlag, 1995.
O’Hara, M.W., and Swain A.M. Rates and risk of postpartum
depression – A meta-analysis. International Review of Psychiatry
Trivers, R. L. (1972) Parental investment and sexual selection.
In B. Campbell (Ed.), Sexual Selection and the Descent of Man (pp.
136-179). London: Heinemann.