Australasian Science: Australia's authority on science since 1938

Antidepressants during Pregnancy Linked to ADHD in Kids

By AusSMC

Exposure to antidepressants in the womb may be linked to attention deficit and hyperactivity disorder in the child, but the risks of depressed mothers stopping their medication may be greater.

“Current psychiatric advice is generally that the risk of ‘depression’ during pregnancy outweighs the risk of foetal exposure to antidepressant medication. These data challenge this assertion and suggest that great caution needs to be exercised in prescribing antidepressants to women who are pregnant or planning to be pregnant because of risks to foetal neurodevelopment.

“Most prior studies have investigated pregnancy outcomes like prematurity and stillbirth. This study represents a considerable advance on previous investigations in using linked electronic health record data from a large population enabling highly specific comparisons to be made between exposed and unexposed groups through each stage of pregnancy and development of children aged 2–19 years. It concluded that there is a near double rate of attention deficit hyperactivity disorder among children whose mothers used antidepressants during pregnancy compared to those who did not.

“Most pregnancy depression is of mild to moderate severity, and mood is known to fluctuate. Evidence-based non-pharmacological approaches, in particular cognitive behavioural therapy to assist management of maladaptive thinking styles, and training in active problem solving are effective. There is Medicare provision for pregnancy mental health care of this kind, but it is under-used. These data indicate that non-pharmacological approaches should be used as a first line treatment and that antidepressants should be preserved for use in the less common severe depression.”

Prof Jane Fisher is Jean Hailes Professor of Women’s Health at Monash University.

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“I would advise women to talk to their doctor if they have concerns. The consequences of suddenly stopping therapy may be drastic. Suicide is a leading cause of maternal death in Australia and New Zealand. Most suicides occur in women with a history of severe mental illness. This risk needs to be weighed against any possible increase in ADHD, which is likely to be influenced by many factors.”

Prof Julie Quinlivan is Pro-Vice Chancellor and Executive Dean of Medicine at the University of Notre Dame Australia.

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“This is a nice study, however a more robust piece would be an epidemiological cohort study in which subjects were not chosen specifically because they were depressed. That is the only way to assess causality, where one takes a large group of subjects (e.g. people born in one city during a certain period of time, follow X women from a catchment area before becoming pregnant etc.) and then follows them and assesses how a particular variable, in this case the use of antidepressants during pregnancy, increases the risk of a given condition.

“It is not clear how big the effect of antidepressant use is. Certainly it is minimal compared to genetic factors. Genetic variability (heritability) explains around 70% of autism cases. Environmental factors are more important in ADHD because they change not only the expression of the disorder but, more importantly, the threshold of diagnosis (for example, the controversy in the USA where the prevalence of ADHD varies by state because of the laws over school entrance).

“Most antidepressants have the same, or similar, mechanisms of action so I would not expect many differences between different types of antidepressants. However, some drugs do have different mechanisms (e.g. influencing dopamine activity) but this study has not been able to assess that question as the sample is too small.

“From the child’s perspective it is likely that the potential harm caused by any increased risk of ADHD or autism would be much less than the potential harm of having a mother suffering from depression. And of course, that is without even mentioning the issue of depression causing mothers to die by suicide during pregnancy. Researchers are only just beginning to realise that it is not psychiatrists, psychologists or neuroscientists that are having the biggest impact on preventing mental health issues – it is gynaecologists.

“In summary, this research does not mean that women should stop taking their antidepressants. It suggests that we need more animal and human research on how this drug affects the normal neurodevelopment of children and then weigh those impacts against the negative consequences of brains developing in stressed and depressed pregnant mothers.”

Dr Celso Arango is Scientific Director of the Spanish Centre for Biomedical Research in Mental Health.

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“Confounding by indication is the bane of all epidemiological studies of drug exposure. This publication recognises the problem but does not have an adequate solution. The final conclusion, that antidepressant exposure in pregnancy does not cause autism but does cause ADHD, strains credibility because the odds ratios on which this conclusion is based are so similar and any differences depend heavily on the modelling of confounds. Rates of exposure to antidepressants were also quite low, so the power of the study is probably limiting.

“It remains possible, even likely, that the effect observed is due to increased genetic risks of psychiatric disorder in the offspring of the women prescribed antidepressants, rather than the effects of the drugs. This was the conclusion for much more certain diagnoses (of birth defects) in a substantially larger sample in which an analogous question was asked (dx.doi.org/10.1136/bmjopen-2012-001148).”

Prof Guy Goodwin is President of the European College of Neuropsychopharmacology.

Source: Clements et al., Molecular Psychiatry, http://dx.doi.org/10.1038/mp.2014.90