Various physical conditions may at first seem to mimic depression. Doctors aim to be on the lookout for these diseases and may order tests to rule them out if one is suspected. Perhaps the most common examples are:
- An underactive thyroid gland - can make you feel quite low, weepy, and tired. A blood test can diagnose this.
- An underactive pituitary gland (hypopituitarism) - the pituitary gland is just under the brain. It makes various hormones which have various actions. Sometimes one hormone can be deficient; sometimes more than one. There are various symptoms that can develop but they can include loss of sex drive, sexual problems, infertility, uncontrollable weight gain and feeling low, depressed and even suicidal. Blood tests can help to diagnose hypopituitarism. There are various causes of hypopituitarism, including head injury.
- Head injury - even a relatively mild one, even many years ago. For example, studies have shown that rates of suicide (presumably related to depression) are more common than average in people who have previously had a head injury. The reason for this is not fully understood. However, one factor that may be significant in some cases is that a head injury may result in hypopituitarism, as discussed above.
- Polymyalgia rheumatica - this condition mainly affects older people. Typical symptoms include stiffness, pain, aching, feeling depressed and tenderness of the large muscles around the shoulders and upper arms. Feeling depressed can be the first main symptom before the other symptoms predominate.
- Early dementia - is sometimes confused with depression.
- Certain drugs, both prescribed and illicit (street) drugs - can cause side-effects which may mimic depression.
- The rest of this leaflet is about depression of unknown cause that is not associated with any physical condition.