Depression is a serious mental health illness that usually makes an individual feel hopeless, low spirited, and unhappy. There are about three million people annually who suffer from depression in the United States. However, there is medication and treatments that can help patients cope with their depression. Although there are multiple types of depression, each has symptoms and treatments of its own. The objective of a recent empirical research study was to test the validity of four Categories of depression by examining the symptoms and risk factors in each category. The four types of depression that were examined are: Major depressive disorder, depressive syndrome, dysthymia, and the comorbid depression condition. They also compared these four types of depression with other psychiatric disorders since depression is known for its psychiatric comorbidities. This research study also questions the lack of evidence in the topic of depression allowing them to further ask whether minor depression is a heterogeneous disorder and if dysthymia really is a different disorder from major depression.This study used the ECA research that was conducted in 1980 to 1983, but they used the information in the follow up study called the Baltimore ECA (which was conducted thirteen years later). The ECA consisted of a series of epidemiologic surveys and the follow up study interviewed 1,920 adults. Originally, there were 3,481 participants, but due to sample loss or the refusal of some participants, the Baltimore study only ended up interviewing 1,920 people. The follow-up sample consisted of older individuals (27-96 years old), and mostly female and Caucasian persons. The data for each patient’s course characteristics, symptoms (if symptoms were due to physical illness or injury, alcohol use, etc.), risk factor (such as stressful events), treatments, and diagnoses were all gathered from the National Institute of Mental Health Diagnostic Interview schedule. The study also used Polychromous regression to examine the differences and similarities for each of the four types of depression used in the study.The analytic strategy in this study was the chi-square tests and analyses of variance which were used to examine the difference in symptoms, courses, etc. for the four types. Also, the Nonparametric Kruskal-Wallis/Mann Whitney tests were used to measure the non-normally distributed. Any differences between two of the four types of depression were compared by means of two-sample tests for continuous variables and categorical variables. To correct any errors, they used the Bonferroni method. They started by examining the univariate suggestions between a set of assumed risk factors- like gender, family history of depression, and traumatic events- for each of the four depressive types. The group that was compared to in this study have not experienced major depressive disorder, depressive syndrome, or dysthymia in their lifetime. After this, they used logistic regression models to test the multivariate suggestions between assumed risk factors in each of the four disorder types. For them to compare the risk factors’ suggested profiles across different groups, they had to use polychromous logistic regression models to test the similarity among these similar ratios/data.The results of this study demonstrated that the symptom profiles for each of the four groups were very similar yet differed in difficulty. The Course characteristics are a bit different. However, results were significantly different with the Risk factor profile. A Family history with depression was most likely with both depressive syndrome and major depressive disorder. Traumatic events were mostly related with depressive syndrome but not much is known about depressive syndrome when it comes to risk factors. Female gender was linked with the comorbid depression category. On the other hand, Dysthymia was the only group that was not linked with any of the specific examined risk factors. Specifically, 17% of the 59 subjects that had major depressive disorder in the ECA study developed comorbid dysthymia during their follow-up. Also, 10% of the 136 patients with depressive syndrome developed major depressive disorder 13 years later; and only 5% developed dysthymia while 8% developed comorbid major depressive disorder and dysthymia. Additionally, 19% of the 37 dysthymia patients developed comorbid major depressive disorder 13 years later. The study’s conclusion indicates that depression in general (expect dysthymia) is hereditarily homogeneous and environmentally heterogeneous. Stress is mostly allied with mild depression, while gender is connected with severe depression. However, the study directs the need to research furthermore in familial transmission of the subthreshold entity, depressive syndrome. Reading through the manuscript made some flaws and limitations in the research study clear. One limitation was the fact that they only interviewed 1,920 adults out of the 3,481 people in the ECA study. Also, the study only tested three risk factors which are social, genetic, and hormonal, but in reality, there are a lot more risk factors for these four groups that were not included. Another limitation could be the fact that most of the participants were females and Caucasian so they didn’t really test for both genders or all races even though they studied a large group of people. On the other hand, a potential flaw in the research could be that individuals were interviewed and depending on the questions that were asked, the subjects could have been affected; the questions could have also been not very thought provoking or critical. Similarly, another flaw could be the fact that most of the subjects were around 48 years old and there weren’t any participants that were under 27 years old. Even though this research is done with a large amount of individuals, it’s not showing a diverse population. In this regard, the results might not be applicable to people under 27, people of color, or a different gender. However, research did a great job with getting participates that are up to age 96. Overall, the research is well thought-out but there should be another study to figure out concepts that this study couldn’t.