Unit 6: Discussion: Neurobiology of Mental Health Disorders
Schizophrenia is a mental illness characterized by positive signs such as hallucinations, delusions, disorganized speech and behaviors, and negative signs which involve a flat affect, slowed mental processing, or the inability to complete daily, self-driven activities such as showering (Hany & Rizvi, 2024), with symptoms generally not showing until early adulthood.
Pathophysiology of Schizophrenia
Schizophrenia is a complex mental disorder where the pathophysiology behind it is not completely understood. However, it is believed the main neurotransmitters associated with schizophrenia are dopamine, serotonin, glutamate, and gamma-aminobutyric acid (GABA), with dopamine playing the greatest role. Studies show excessive dopamine activity in the mesolimbic pathway (associated with reward, motivation, and reinforcement learning) of the brain contributes to positive symptoms; while decreased dopamine activity in the mesocortical pathway (associated with concentration, attention, cognitive function) leads to the negative symptoms (Hany & Rizvi, 2024). Glutamate and GABA are released in co-junction of dopamine. The GABA neurons have a reduced detection in the GABA transmitter, which results in decreased brain-derived neurotrophic factor (BDNF) signaling. The BDNF will then increase glutamate transmission, which affects neuron survival and CNS function (Luvsaannyam et al., 2022).
Risk Factors
There are over 100 genes linked to schizophrenia – with the most susceptible ones including NRG1, DTNBP1, COMT, DISC1, DRD2, and GRM3 (Stilo et al., 2011).
Risk factors for schizophrenia in the fetal life include prenatal maternal infections, complications (diabetes, pre-eclampsia, bleeding), or inadequate nutrition, delivery complications, season of birth (higher correlation in winter months), and older parental age. In early life, risk factors can be hearing impairment or childhood trauma, and in later life include social factors such as exclusion, parental loss, or stressful life events (Stilo et al., 2011). Other factors can include family history of schizophrenia, abuse of psychoactive or psychotropic drugs (Mayo Clinic Staff, 2024), or being male in gender.
Neuroimaging and Schizophrenia
Since brain function correlates with brain structure, various imaging studies have been utilized to study those diagnosed with schizophrenia. Xenon inhalation and SPECT scans study the cerebral blood flow though, PET scans measure metabolism and blood flow. Blood oxygenation Level Dependent (BOLD) functional MRIs (fMRIs) and Arterial Spin Labeled (ASL) MRIs provide imaging of neural activity and microvascular function (Keshavan et al., 2019). fMRIs allow radiologists to “measure neuronal activity indirectly through changes in blood flow and oxygen metabolism, ASL measures cerebral blood flow (CBF) directly by inverting the magnetization of the arterial blood water using radiofrequency (RF) pulses to create an endogenous diffusible trace” (Keshavan et al., 2019, para. 5).
Resources
Hany, M. & Rizvi, A. (2024). Schizophrenia. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK539864/Links to an external site.
Keshavan, M. S., Collin, G., Guimond, S., Kelly, S., Prasad, K. M. & Lizano, P. (2019). Neuroimaging in schizophrenia. Neuroimaging Clinics of North America, 30(1), 73-83. https://pmc.ncbi.nlm.nih.gov/articles/PMC7724147/#:~:text=PET%2C%20SPECT%20and%20magnetic%20resonance,%2C%20serotonin%2C%20GABA%20and%20glutamateLinks to an external site..
Luvsannyam, E., Jain, M. S., Pormento, M. K. L.., Siddiqui, H., Balagtas, A. R. A., Emuze, B. O. & Poprawski, T. (2022). Neurobiology of Schizophrenia: A Comprehensive Review. Cureus. https://pmc.ncbi.nlm.nih.gov/articles/PMC9080788/Links to an external site.
Mayo Clinic Staff. (2024, October 16). Schizophrenia. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/schizophrenia/symptoms-causes/syc-20354443#:~:text=Risk%20factors&text=A%20family%20history%20of%20schizophrenia,that%20may%20affect%20brain%20developmentLinks to an external site.
Stilo, S. A., Di Forti, M. & Murray, R. M. (2011). Environmental risk factors for schizophrenia: implications for prevention. Neuropsychiatry 1(5). https://www.jneuropsychiatry.org/peer-review/environmental-risk-factors-for-schizophrenia-implications-for-prevention-neuropsychiatry.pdfLinks to an external site.
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Instructions:
Provide 2-4 follow-up questions for students to consider in their peer responses.
- Reflect on the mental health disorder chosen by your peer. Do you agree with their discussion of the neurobiological mechanisms? What information could you add to their discussion?
- Compare the neurobiological mechanisms of the disorder that you chose with the one chosen by your peer. What significant differences do you identify. Are there any similarities?
- In your research for this weeks’ post, did you find any new research or evidence related to genetic and environmental factors that influence the risk of mental health disorders? How can you use this information to elaborate on a peer’s initial discussion post?
Responses need to address all components of the question, demonstrate critical thinking and analysis, and include peer reviewed journal evidence to support the student’s position.
Please be sure to validate your opinions and ideas with citations and references in APA format.
Please review the rubric to ensure that your response meets the criteria.
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