Just beyond the luster of our modern sensitivity to pediatric and adolescent mental health, an equally pressing psychiatric crisis shivers in cold obscurity: the difficulty in diagnosing and treating adult-onset mental illness. 

The inclination to primarily study mental illness as it affects the young is, at first glance, understandable. For one, the cognitive and behavioral symptoms of psychopathology often reveal themselves early on in one’s development. There may be clinical insights that studying children can exclusively yield. Also, many studies are designed less in the hopes of informing diagnosis and treatment, and more towards ascertaining the theoretical roots of why certain people are prone to illness, while others remain cognitively and emotionally spry; the architects of such studies may well be striving to add their own voice to the ongoing debate of nature-or-nurture, a favorite among developmental psychologists and theologians alike. While all the above are sound and worthy motivations for research, one fears that their popularity leaves little funding for scholarship that investigates the rarer adult-onset psychological disorders. As a result of this deficit in the literature, one may invariably believe that the prevalence of adult-onset mental illness is low, even aberrant. Such a misconception betrays a larger ignorance of the concept that this essay seeks to describe and explore—neuroplasticity.

Neuroplasticity is defined as “the ability of the nervous system to change its activity in response to intrinsic or extrinsic stimuli by reorganizing its structure, functions, or connections” (Puderbaugh and Emmady, 2022). Physical events, like traumatic brain injuries, have been shown to yield a predictable set of changes in the brain’s structure; for instance, if the corticobulbar nucleus of stroke patients suffering from dysphagia (the inability to swallow) is stimulated, it causes the cortex to rewire itself, which improves one’s ability to swallow without assistance (Su et al., 2016). Even more remarkably, emotional experiences rewire our brains too. fMRI images show that, after a traumatizing incident, one’s amygdala becomes overactive, and the medial prefrontal cortex shrinks in size (Shin et al., 2006). Both regions are heavily involved in regulating responses to threats, so their respective adjustments in people with post-traumatic stress disorder make sense here. Of course, this reorganization of the brain is an overreaction—it provokes intense bouts of anxiety and panic in response to ultimately harmless events. 

As these anecdotes show, neuroplasticity is not inherently good or bad; it is simply our brain’s attempts, with mixed success, to adapt itself to the circumstances of our life. However, the fact that the brain changes dramatically throughout the entire lifespan heightens the risk that adults with limited or nonexistent histories of mental illness will develop psychopathological disorders later in life. Therefore, it is imperative to investigate adult mental health screening and diagnostic tools more thoroughly. Resources ought to be targeted at adults who have risk factors and family histories of schizophrenia and other psychotic disorders, as these often emerge decades after puberty. 

For example, schizophrenia develops at a far older age than most other psychopathologies (Kessler et al., 2007). In schizophrenics, one’s “earliest signs of any mental disturbance occurred before puberty, but psychotic symptoms and index admissions for the full syndrome were confined to the decade and a half after puberty” (Jones, 2018). It is well documented that in women, symptoms of schizophrenia often won’t reveal themselves until one’s late fifties, or even sixties; some psychologists argue that the hormonal and neurological changes associated with menopause catalyze one’s first (diagnosable) psychotic episode (Jones, 2018). Schizophrenia is emblematic of a host of mental disorders that can develop or come on rapidly in adulthood. In order to develop effective diagnosis and treatment plans for schizophrenia, the current scholarly literature needs a more robust investigation of neuroplasticity and brain changes in adults.

While neuroplasticity can lead to maladaptive changes in brain circuitry, experimenters have found that certain lifestyle choices that can ward off cognitive decay and disorganization transpire as one ages. Exercise, for example, has been shown to counteract the decline in neurogenesis (“the process by which new neurons are formed in the brain”) that often occurs in one’s elderly years (Pittenger & Duman, 2007; Queensland, 2023). Surprisingly, antidepressants have been shown to have a similar effect (Pittenger & Duman, 2007). Future research should not simply investigate ways to diagnose and treat adults whose neurological changes have imperiled their mental health; rather, scholars should identify habits that people can integrate into their daily routine to combat the negative neurological effects of aging. Because elderly adults often have more limited access to clinical care than young people, who may have the benefit of school-based psychologists and institutional support systems, these practices may be more valuable tools in adults’ arsenals against cognitive decline. 

The topics that monopolize the attention of the neuroscientific community, like the brain itself, may change and transform rapidly for the time being. It bears noting that the current focus on diagnosing and treating mentally ill young people is, of course, as important a cause to invest in as any. However, we cannot allow the dazzle of this worthy cause to blind us to another urgent mental health crisis—the onset of psychopathological disorders in adults due to changes in brain chemistry. In all likelihood, insights into the study of neuroplasticity will drive positive changes that will also be informative in addressing psychopathology in younger people.

To conclude, the human brain is volatile, fitful, and fickle. Like us, it has a tendency to overreact and over-correct, even when it means well. And until we devote significant resources to our understanding of neuroplasticity, across patients of all ages, our ability to combat debilitating mental illnesses will be just that: well-meaning, but rudimentary. ​


About the Author
Will Engelmayer is a senior at Harvard College, concentrating in Psychology, with a secondary in Government.

References

• D'Sa, C., & Duman, R. S. (2002). Antidepressants and neuroplasticity. Bipolar disorders, 4(3), 183-194.
• Jones, P. B. (2013). Adult mental health disorders and their age at onset. The British Journal of Psychiatry, 202(s54), s5-s10.
• Kessler, R. C., Amminger, G. P., Aguilar-Gaxiola, S., Alonso, J., Lee, S., & Üstün, T. B. (2007). Age of onset of mental disorders: a review of recent literature. Current opinion in psychiatry, 20(4), 359-364.
• Pittenger, C., Duman, R. (2007). Stress, Depression, and Neuroplasticity: A Convergence of Mechanisms. Neuropsychopharmacol. https://doi.org/10.1038/sj.npp.1301574
• Queensland. (2023). What is neurogenesis? The University of Queensland: Australia. https://qbi.uq.edu.au/brain-basics/brain-physiology/what-neurogenesis
• Shin, L. M., Rauch, S. L., & Pitman, R. K. (2006). Amygdala, medial prefrontal cortex, and hippocampal function in PTSD. Annals of the New York Academy of Sciences, 1071(1), 67-79.
• Su, Y. S., Veeravagu, A., & Grant, G. (2016). Neuroplasticity after traumatic brain injury. Translational research in traumatic brain injury.