Differential diagnoses of depression

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.

[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.

In addition individuals with CFS symptoms often have an undiagnosed medical or psychiatric disorder such as diabetes, thyroid disease or substance abuse.

[62] Most tumors are considered to be benign and are often an incidental finding discovered during autopsy or as of neuroimaging in which case they are dubbed "incidentalomas".

[28][69] Post-concussion syndrome (PCS), is a set of symptoms that a person may experience for weeks, months, or occasionally years after a concussion with a prevalence rate of 38–80% in mild traumatic brain injuries, it may also occur in moderate and severe cases of traumatic brain injury.

[70] A diagnosis may be made when symptoms resulting from concussion, depending on criteria, last for more than three to six months after the injury, in which case it is termed persistent postconcussive syndrome (PPCS).

[71][72][73][74][75] In a study of the prevalence of post concussion syndrome symptoms in patients with depression utilizing the British Columbia Postconcussion Symptom Inventory: "Approximately 9 out of 10 patients with depression met liberal self-report criteria for a postconcussion syndrome and more than 5 out of 10 met conservative criteria for the diagnosis."

[78] Multiple sclerosis is a chronic demyelinating disease in which the myelin sheaths of cells in the brain and spinal cord are irreparably damaged.

Symptoms of depression are very common in patients at all stages of the disease and may be exacerbated by medical treatments, notably interferon beta-1a.

The results of one recent study suggest that smoking cigarettes may have a direct causal effect on the development of depression.

The emerging field of nutritional neuroscience explores the various connections between diet, neurological functioning and mental health.