Recently, the world has seen a rise in mental illnesses. Disorders such as depression and anxiety are more common now than ever. Although they are becoming increasingly more common, there is still a negative stigma attached to such psychiatric disorders. This research report serves to inform the reader about psychiatric disorders, specifically borderline personality disorder. The report highlights the effects of the disease and it examines which parts of the brain have to do with it. Through research it has been determined that borderline personality disorder (BPD) is caused by both a mix of genetic and environmental factors. To conduct this research I utilized a variety of academic articles along with additional websites that helped me to determine the meaning of certain scientific jargon. The majority of my research has come from works by Ali Amad et al., Falk Leichsenring et al., and Xingqun Ni et al.. According to the National Institute of Mental Health, BPD is “a mental illness marked by an ongoing pattern of varying moods, self-image, and behavior.” The results of this disease can have crippling effects on a person including severe mood changes, depression and anxiety. Depression can then lead to suicide, a rampant problem in today’s world. Unfortunately, suicide is in the top ten leading causes of death in the United States (CDC). This is why BPD is especially important to research; hopefully, with more understanding of the biochemistry of this disease, comes a greater acceptance by the public. An understanding of this disease may contribute to better lives for those living with this disorder. To diagnose BPD, five out of nine criteria must be met. These nine criteria can be found in Appendix 1. These “requirements” highlight the various symptoms that BPD may manifest itself in. As one can see, it is a very serious condition that calls for extensive research by scientists in order for them to develop better treatments to calm some of these intense symptoms. As previously stated, the factors that induce borderline personality disorder are a mixture of both genetic and environmental components. These environmental aspects may include things such as unfortunate childhood events or abuse. Familial studies conducted also prove that BPD is genetic. For example, Ali Amad et al. state, “Recently, the presence of familial aggregation was confirmed because the risk of a BPD diagnosis…in the relatives of a proband with BPD (prevalence of 14.1%) was 3.9 times higher than the risk of diagnosis in the relatives of a proband without BPD (prevalence of 4.9%, p < .001)." Thus, genetics do play a role in the inheritance of BPD. To further confirm this theory, twin studies were conducted in order to determine the "heritability" of BPD. Heritability is, "defined as the proportion of observed variation that can be attributed to inherited genetic factors rather than environmental factors, can be estimated from the difference in the correlation between monozygotic (MZ) and dizygotic (DZ) twins." In one study, a small number of twin pairs were used and the results came up as inconclusive. However, with further studies it was deduced that the heritability was around 30- 40%. It is extremely clear from these studies that genetics and heritability are prominent factors in BPD. Although genes are clearly relevant to this mental illness, no specific genes have been defined as "causative" yet. While the specific cause is still unknown, there are some genes that are of interest to scientists because they relate to the various symptoms of the disorder. For example, the "impulsive aggression, common in patients with borderline personality disorder, is associated with reduced serotonergic responsiveness, and some genes that might be linked to psychopathological changes in the disorder are involved in the serotonergic system" (Leichsenring). This idea references serotonin, a chemical in the body that serves many different functions, one of which includes its ability to act as a mood stabilizer and combat depression and anxiety. Thus, it has been found that some genes that are synonymous with serotonin, may have something to do with the disorder and its progress in the human brain. In fact, in one study it was shown that there was a correlation between a short allele in the serotonin transporter gene (5-HTTLPR) and BPD. This study also showed that "compared with healthy controls, patients with BPD showed higher frequencies of the 10 repeat of the VNTR marker and the S-10 haplotype, and fewer 12 repeat and LA-12 haplotype" (Ni). However, this correlation was not found in another study that was conducted and it might have been found in the first place due to a treatment that is commonly administered to patients with BPD. Throughout their research of BPD, scientists have also used structural MRI's in order to analyze the brains of patients with the illness. They focused on the volume of the amygdala when conducting their studies of the brain. Unfortunately, no correlation between the size of the amygdala and BPD was found. If there was any noticeable volume change, it was chalked up to the idea that it was most likely caused by post traumatic stress disorder (several patients that suffer from BPD also suffer from PTSD). Furthermore, functional MRI scans of the brains were also done. These scans revealed that when a patient with BPD was shown an emotionally upsetting image, they had greater activity in the amygdala as opposed to the controlled subjects. The accumulation of the research points to the idea that the functions of the amygdala most definitely have something to do with BPD. PET scans were also done to analyze the brains of patents with BPD. A PET scan stands for Positron Emission Tomography and it uses radiotracers in order to evaluate the functionality of organs and tissues (https://www.radiologyinfo.org/en/info.cfm?pg=pet). In these PET scans, a lower frontal glucose metabolism was found, signalling to scientists that BPD may be accompanied by "frontolimbic dysfunction". Furthermore, women without BPD who recalled traumatic past events were recording having an increase in blood flow to the prefrontal cortex. Women who have experienced trauma and who have BPD did not have the same increase in blood flow. This tells scientists that there may be a malfunction in the "prefrontal" areas of the brain. These malfunctions in the prefrontal areas are believed to contribute to the violent mood swings that those with BPD tend to experience. Based on the entirety of this research done by Leichsenring et. all, it has been determined that the best treatment for BPD involves a combination of both psychotherapy as well as pharmacotherapy. Psychotherapy refers to the ways in which BPD may be treated without the use of medicine (e.g. talk therapy) (https://www.psychiatry.org/patients-families/psychotherapy). Likewise, pharmacotherapy refers to the ways in which mental illnesses can be treated using drugs. Studies that involved legitimate drugs as well as placebos reported that drugs did not work especially well for treating BPD as a whole. Certain drugs such as amitriptyline and imipramine (antidepressants) worked well in treating depression, a side-effect of BPD. Additionally, other drugs such as Phenelzine where reported to reduce hostility, but Phenelzine was ineffective in treating depression. There were a variety of other drugs tested, but the results remained just as scattered and inconclusive. The inconsistency of the outcomes of these tests proves that while pharmacotherapy may contribute some to the treatment of BPD, it is difficult to choose one drug over another. Psychotherapy still remains as the most effective treatment of BPD. With my limited knowledge on genetics and biochemistry, it was quite difficult to understand all of the meaningful research that has been conducted on BPD. However, I have learned that BPD may arise from a variety of influences, some genetic and some not. Although environmental aspects may contribute to this illness, genetics is most certainly to blame for the majority of the symptoms. Similar to other mental illnesses, BPD is extremely serious and should not be taken lightly. The research that scientists are currently conducting is a brilliant way to further the treatment options for patients with BPD. Perhaps in the future scientists will be able to develop drugs that treat all symptoms, rather than just specific ones. If I had to make a prediction for how this may be done based on my research, I would guess that the drugs would target the amygdala. In the research that I read about, the amygdala was considered to be one of the mains sources for the emotional upset that comes with BPD. I hope that in the near future, an effective solution is developed that may better the lives of patients with BPD.