Association or causality?
Pedersen et al's paper (1) is a welcome addition to research of this
subject. The importance of such work is confirmed by Durrani and
Cantwell's paper in this month's British Journal of Psychiatry (2) which
found that 43% of patients referred to a community perinatal mental health
team were taking antidepressants at conception, with the most common drugs
taken being SSRIs.
A weakness of the study is that there was no control group of women
with untreated mental illness. Given the population-based design of the
study with the use of national databases and registries, such a control
group should be identifiable. Without such data, it is impossible to be
certain that there is no association between septal heart defects and the
underlying mental illness itself. This study assumes causality of septal
heart defects to citalopram and sertraline but without a true control
group, we can make no such assumption.
Previous research has revealed an association between mitral valve
prolapse and panic disorder (3). It is therefore entirely possible that
other neuroses may be associated with congenital cardiac defects.
(1) Selective serotonin reuptake inhibitors in pregnancy and
congenital malformations: population based cohort study. Lars Henning
Pedersen et al. BMJ 2009;339:b3569
(2) Characteristics of patients seen by a community perinatal mental
health service. Durrani A, Cantwell R. Psychiatric Bulletin 2009;33:368-
(3) Prevalence of panic disorder in mitral valve prolapse: a
comparative study with a cardiac control group. Sivaramakrishnan K,
Alexander PJ, Saharsarnamam N. Acta Psychiatrica Scandinavica 1994;89:59-
Competing interests: No competing interests