Differential diagnoses of depression

This section is written like a personal reflection, personal essay, or argumentative essay that states a Wikipedia editor's personal feelings or presents an original argument about a topic. Please help improve it by rewriting it in an encyclopedic style. (December 2020) (Learn how and when to remove this message)

Depression, one of the most commonly diagnosed psychiatric disorders,^[2][3] is being diagnosed in increasing numbers in various segments of the population worldwide.^[4][5] Depression in the United States alone affects 17.6 million Americans each year or 1 in 6 people. Depressed patients are at increased risk of type 2 diabetes, cardiovascular disease and suicide. Within the next twenty years depression is expected to become the second leading cause of disability worldwide and the leading cause in high-income nations, including the United States. In approximately 75% of suicides, the individuals had seen a physician within the prior year before their death, 45–66% within the prior month. About a third of those who died by suicide had contact with mental health services in the prior year, a fifth within the preceding month.^{[6][7][8][9][10]}

There are many psychiatric and medical conditions that may mimic some or all of the symptoms of depression or may occur comorbid to it.^[11][12][13] A disorder either psychiatric or medical that shares symptoms and characteristics of another disorder, and may be the true cause of the presenting symptoms is known as a differential diagnosis.^[14]

Many psychiatric disorders such as depression are diagnosed by allied health professionals with little or no medical training,^[15] and are made on the basis of presenting symptoms without proper consideration of the underlying cause, adequate screening of differential diagnoses is often not conducted.^{[16][17][18][19][20][21]} According to one study, "non-medical mental health care providers may be at increased risk of not recognizing masked medical illnesses in their patients."^[22]

Misdiagnosis or missed diagnoses may lead to lack of treatment or ineffective and potentially harmful treatment which may worsen the underlying causative disorder.^[23][24] A conservative estimate is that 10% of all psychological symptoms may be for medical reasons,^[25] with the results of one study suggesting that about half of individuals with a serious mental illness "have general medical conditions that are largely undiagnosed and untreated and may cause or exacerbate psychiatric symptoms".^[26][27]

In a case of misdiagnosed depression recounted in Newsweek, a writer received treatment for depression for years; during the last 10 years of her depression the symptoms worsened, resulting in multiple suicide attempts and psychiatric hospitalizations. When an MRI finally was performed, it showed the presence of a tumor. However, she was told by a neurologist that it was benign. After a worsening of symptoms, and upon the second opinion of another neurologist, the tumor was removed. After the surgery, she no longer had depressive symptoms.^[28]