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Bipolar disorder and schizophrenia are two of the most common severe mental illnesses, causes of which still not known well. However, new developments regarding the origins of the diseases and how they cause a metamorphosis in an individual keep coming to light. A recent study concludes that a genetic variant - synaptosomal associated protein (SNAP25) - is responsible for increasing an individual's risk for developing these diseases.
According to study author Stephane Jamain, a promoter variant of SNAP25 - rs6039769 - is associated with the early onset of bipolar disorder and is also responsible for "higher gene expression level in human prefrontal cortex." A gene has several control sites that are involved in the process of transcription, including the start site, the promoter, enhancers and silencers that function similar to the name.
Variant associated with larger amygdala volume
The researchers used genetic analysis and neuroimaging in samples of adults with schizophrenia and traces of starting symptoms of bipolar disorder along with postmortem analysis of brain tissues from schizophrenia patients. They compared these with those of the control group and found that the SNAP25b: SNAP25a ratio was higher in schizophrenic patients who had the rs6039769 at-risk allele (alternative forms). The study also used genetic imaging and revealed that "male risk carriers had an increased amygdala-ventromedial prefrontal cortex functional connectivity and a larger amygdala than non-risk carriers." The genetic mutation was responsible for the way the SNAP25 protein was expressed in the brain, which could affect the way information was processed between the brain regions involved in regulating emotions.
Larger amygdala volume has been implicated for bipolar disorder in past studies as well. The amygdala dons several roles from spurring the fight-or-flight mechanism to emotional control and regulation. It connects with the ventral prefrontal cortex (VPFC), responsible for modulating responses related to external emotional cues and inner stimuli. Lack of connectivity between the VPFC and the amygdala makes an individual feel anxious and stressful even in day-to-day situations as a result of "emotion homeostasis." Elucidating on this link, a review article by Stephen Strakowski of the University of Cincinnati said, " Effectively, with diminished prefrontal modulation, the limbic brain is hypothesized to be dysregulated, leading to the emotional extremes of mania, depression, and mixed states."
Timely diagnosis vital to productive life
According to the National Institute of Mental Health (NIMH), people suffering from bipolar disorder undergo unusually intense emotional states during distinct periods called mood episodes. Each mood episode represents a drastic change from a person's usual mood and behavior. An overly joyful or overexcited state is called a manic episode, and an extremely sad or hopeless state is called a depressive episode. Increased activity levels can be followed by long periods of depression.
Timely recognition of mental health disorders is extremely important to help a person lead a healthy and productive life. It therefore becomes vital to rely only on a qualified doctor or psychiatrist for medications. Self-medication and substance abuse to mitigate the effects can make the problem worse. Some medications like antidepressants are known to increase the risks of mania in patients who are already susceptible to developing bipolar disorder.
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