Prozac and Brain Cell Growth: Age and Sex Dependent

Treatment of depression in adolescents is a delicate matter. On the one hand, the Food and Drug Administration has warned physicians and pharmacists that antidepressant use in children may increase the risk of suicidal thoughts and behavior. Most parents have by now heard this warning and are equally concerned if their children show symptoms of depression. On the other hand, failure to adequately treat depression almost guarantees ongoing episodes of the disease. Research has demonstrated that, with childhood and adolescent depression especially, swift and early intervention is crucial. Yet another wrinkle in the story is the fact that few studies have looked into the long-term effects of antidepressant use in children and young adults. The only such medication currently approved for pediatric use is Prozac (fluoxetine). Nevertheless, many psychiatrists are reluctant to prescribe Prozac to their younger patients simply because there are so many unanswered questions.

Studies of adult male rodents and primates revealed that Prozac administered for long enough periods actually alters neurogenesis in certain regions of the brain, such as the hippocampus. Neurogenesis is the growth of new brain cells and is a vital aspect of cognitive development. Scientists also theorize that neurogenetic enhancement is one of the means by which antidepressant medications produce their positive effects. In a recent study of Prozac’s effects on neurogenesis, pubescent and adult rats of both sexes were exposed to the medication over the course of several days. The results raised as many questions as answers. Examination of brain tissue revealed that only adult male rats experienced increased growth of neurons. However, these cells died off in larger numbers than usual, resulting in zero net gain. In female rats and pubescent rats of both sexes, no extra growth was observed. Strangely, the survival rate of new cells in the female rats’ hippocampi was actually lower than normal.

Neurogenesis is an important but little-understood mechanism of brain development. Antidepressant medications often alter the rate of new brain cell growth as part of their therapeutic action. As the rat study revealed, these effects are highly dependent on both age and sex. That’s not to say that one medication is necessarily better for one sex or the other. Prozac and other antidepressants achieve their mood altering effects in numerous ways, and the benefits to females might be achieved in ways other than via hippocampal cell growth. As for the prescription of Prozac for adolescents, no evidence has been produced to indicate that neurogenetic alterations during puberty will lead to cognitive impairments later in life.


  1. National Center for Biotechnology Information. (n.d.). Fluoxetine. PubMed Health. Retrieved April 11, 2012, from
  2. Hodes, G.E., Yang, L., VanKooy, J., Santollo, J. & Shors, T.J. (2009). Prozac during puberty: distinctive effects on neurogenesis as a function of age and sex. Neuroscience, 163, (2), 609-617.

© Copyright 2012 All rights reserved.

The preceding article was solely written by the author named above. Any views and opinions expressed are not necessarily shared by Questions or concerns about the preceding article can be directed to the author or posted as a comment below.

Leave a Comment

By commenting you acknowledge acceptance of's Terms and Conditions of Use.

* Indicates required field.

GoodTherapy uses cookies to personalize content and ads to provide better services for our users and to analyze our traffic. By continuing to use this site you consent to our cookies.