Smoking in Pregnancy Linked to Risk of Schizophrenia Diagnosis in Later Life

Justin Karter
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In the first study of its kind, researchers from Finland found the “most definitive evidence to date” that smoking during pregnancy is associated with the eventual diagnosis of schizophrenia in offspring.  After controlling for other potential variables, the study, published ahead of print in The American Journal of Psychiatry, revealed a 38% increased odds of developing symptoms diagnosed as schizophrenia in young adults who were exposed to high levels of nicotine in utero.

“Prenatal nicotine exposure during gestation was related to an increased odds of schizophrenia.”
“Prenatal nicotine exposure during gestation was related to an increased odds of schizophrenia.”

“In this nationwide population-based nested case-control study of nearly 1,000 schizophrenia subjects, we demonstrated an association between maternal nicotine exposure, quantified as cotinine during gestation, and schizophrenia in offspring,” the researchers write.

Past studies indicate that somewhere between 12% and 25% of women in Western societies smoke during pregnancy. This makes nicotine exposure one of the most common form of neurodevelopmental fetal abnormalities.

It is currently understood that nicotine crosses the placental barrier in pregnant women and can specifically impact the process of fetal brain development, with both short and long term consequences. In addition, new research is signaling that nicotine exposure can trigger epigenetic changes which can adversely impact the normal brain and behavioral developments.

Studies on the etiology of, and risk factors for, the development of symptoms associated with psychosis and schizophrenia are limited in several ways.  Several experts have challenged schizophrenia as a disease classification, while many others take issue with current decontextualized understandings of symptoms and the field’s overall failure to “train a wide angle, multidisciplinary lens on psychological disturbance.” In addition, attempts to look a purely biological risk factors are made problematic by findings of robust connections between trauma, especially childhood sexual abuse and bullying, with the emergence of symptoms related to psychosis, such as delusions and hearing voices.

The existing research on environmental and prenatal risk factors for the development of these symptoms is also complicated by the limited and contradictory nature of previous findings. Unlike all previous research, however, the current study was able to make use of a much larger sample size and examine precise amounts of nicotine exposure.

Using a nested case-control design, the Finnish Prenatal Study of Schizophrenia examined all offspring born in Finland from 1983 to 1998 with follow-up through 2009.  Nearly all pregnancies (98%) during this time were subjected to sampling that revealed nicotine exposure levels in the body. This data was then matched to the Finnish population registry and healthcare data, which includes information about diagnoses and hospitalizations. The researchers identified 977 cases of young adults (average age 22.3) who had been diagnosed with schizophrenia and whose mothers had also given samples during pregnancy.

After controlling for maternal and paternal age, parental history of psychiatric diagnoses, and place of birth, all factors that appeared to influence the likelihood of a schizophrenia diagnosis, the researchers found a significant association between the level of nicotine exposure during pregnancy and the odds of being diagnosed with schizophrenia.

Also, because it is known that smoking can cause low weight births, the study tested whether or not the decreased birth weights could account for the association. The change in birth weight did not appear to account for the connection between nicotine exposure and schizophrenia diagnosis.

“Given the high frequency of smoking during pregnancy, these results, if replicated, may ultimately have important public health implications for decreasing the incidence of schizophrenia,” the researchers conclude.

Speaking to Medscape, Stephen Faraone, PhD, a professor of psychiatry at the State University of New York Upstate Medical University, cautioned: “It’s important for readers to understand that, like all other risk factors for schizophrenia, the increased risk due to smoking is low. That means it is unlikely that maternal smoking can account for all schizophrenia cases. Future research will need to determine if the effects of maternal smoking interact with other genetic and environmental risks to cause schizophrenia.”

 

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Niemelä, S., Sourander, A., Surcel, H.M., Hinkka-Yli-Salomäki, S., McKeague, I.W., Cheslack-Postava, K. and Brown, A.S., 2016. Prenatal Nicotine Exposure and Risk of Schizophrenia Among Offspring in a National Birth Cohort. American Journal of Psychiatry, pp.appi-ajp. (Abstract)

7 COMMENTS

  1. “’Given the high frequency of smoking during pregnancy, these results, if replicated, may ultimately have important public health implications for decreasing the incidence of schizophrenia,’ the researchers conclude.”

    My mother did not smoke, but I did end up suffering from “the classic symptoms of schizophrenia,” according to my psychiatrist’s opinion, written in his medical records.

    My subsequent decade plus of medical research found that, instead, what my psychiatrists and doctors thought was either “bipolar” or “the classic symptoms of schizophrenia, was actually the central symptoms of poly pharmacy induced anticholinergic intoxication syndrome. These are the central symptoms of neuroleptic / antidepressant induced anticholinergic intoxication syndrome, according to drugs.com:

    “memory loss, disorientation, incoherence, hallucinations, psychosis, delirium, hyperactivity, twitching or jerking movements, stereotypy, and seizures.”

    And they are almost the exact same symptoms as “schizophrenia,” the only difference being “hyperactivity” vs. “inactivity.” But the neuroleptics do make all people staggeringly tired, thus sleep too much, which confuses the medical community. Thankfully, my symptoms only existed while I was on multiple neuroleptics and / or other poly pharmacy, and the symptoms went away once I was weaned from the drugs. These are the drug classes known to cause anticholinergic toxidrome:

    “Substances that may cause this toxidrome include the four ‘anti’s of antihistamines, antipsychotics, antidepressants, and antiparkinsonian drugs[3] as well as atropine, benztropine, datura, and scopolamine.”

    Thus, today’s current “bipolar” drug cocktail recommendations, which encourage poly pharmacy with the antidepressants and antipsychotics is unwise. Unless the goal of the psychiatrists, who created the guidelines, is to iatrogenically create “psychosis,” with drugs, in innocent people, for profit.

    If “decreasing the incidence of schizophrenia” is, in fact, the goal of the public health researchers, I’m quite certain the medical community at large needs to be reminded that ADRs of the antidepressants and antipsychotics can result in anticholinergic toxidrome, which the medical community is incapable of distinguishing from “the classic symptoms of schizophrenia.”

    And, just one more note, I do smoke (it was a misdiagnosis of the common ADRs of a claimed “safe smoking cessation med” / antidepressant, Wellbutrin, that actually resulted in my initial DSM-IV-TR “bipolar” misdiagnosis). And I did smoke minimally during my pregnancies, but neither of my children have ever suffered from any “mental illness” problems.

    Quite to the contrary, one of my children was the valedictorian of his high school class, and is doing great in college, has a 3.9 something GPA going into his senior year of college. And my daughter just graduated from high school winning, “the most significant honor bestowed upon a young woman at … It is given to the senior, whose actions and demeanor bespeak self-respect, courteous consideration for others, and loyalty to the academy and its traditions. She must be a leader in scholarship and other school activities….”

    Kudos to my sweet girl! And pardon the proud mom. But my point is the medical community is villainizing (defaming and poisoning, which are illegal behaviors) those of us who smoke; despite smoking being legal in this country.

    The public health officials should be looking into the known ADRs and drug interactions of the psychiatric drugs, if they truly want to decrease the incidence of “schizophrenia.” Let’s see if they replicate the study’s findings, which may not be likely, given the psychiatric and psychological industries’ dismal track records on replicating studies.

    • Bpd, Exactly.

      We all catastrophise and everyone has their own stuff inside in their heads.

      Trauma can makes things more difficult but there are ways of improving this.

      Bipolar is the same.

      My GP had a good term:- “Burnout” (for his own breakdown that is – the patients were still “nutters”).

  3. A study from John Hopkins University says men live longer than the men that point out a women’s weight.

    I mention that, because 21 years into my mental health challenges and I don’t understand it. Most studies mean zilch to me. I’ve had to figure nearly all of it out on my own with literally no answers. I didn’t have a history of trauma before psychosis arrived in my life. It has been quite a journey both good and bad.

  4. I wish we could say we’d found this “schizophrenia” that this study suggests is caused by cigarette smoking, but we haven’t found it yet. Okay. According to this research study, pregnant women smoking cigarettes have “schizophrenic” children, but only in Finland. Until the research can be replicated elsewhere, I guess, pregnant women who smoke cigarettes should think twice about visiting Finland. .

  6. The single best event of my life was beginning an extensive massage therapy regimen. My doctor recommended a fancy spa near my neighborhood, but I decided a different one was the right choice for me. They didn’t accept my insurance, but that didn’t bother me. I only needed to go once a week, but I have to admit I went three times a week, because that’s where my woman resided. I spent WAY too much money, but it was worth every penny. I definitely would have spent more. Now I don’t bother reading mental health articles anymore that lead to sleepless nights trying to decipher if this applies to me.