Your friend could ask her doctor to give her a blood test, that way iron deficiency or thyroid problems would show up and be treated. If she has got depression it may be that you can suggest she sees a therapist. It's possible something has happened to trigger off a depression, a loss or even unresolved loss can precipitate such a reaction. Often the person who is depressed is unaware of the cause themselves, that's where therapy can really help.

Its quite possible. My mum was misdiagnosed with depression because she was tired all the time, didn't feel like getting out of bed, loss of appetite etc. She had a low Hb (anaemia), which later turned out to be a symptom of having cancer. I'd advise her to ask for a full blood screening.

I do not know a good enough answer for your first question, but your second I know that iron and especially B12 is important for mental health. Get another opinion.

There are so many different physical illnesses that can cause depression that often a diagnosis of depression is a cop out for a doctor who doesn't want to keep digging. My husband went to the doctor with depression and found out he had heart disease. One stent later and the depression was gone. Of course, the cardiologist mocked our family doctor and never said "sorry" when he found the blockage, but nevertheless our family doctor was right. In my own case, depression was being caused by fibromyalgia. It is really hard not to get depressed when you are in constant, unrelenting pain. I've seen enough of this kind of stuff that I don't know that I would ever accept a diagnosis of depression without digging deeper. Depression is a symptom and rarely a disease.

Hi I was ill when I was 15, and they could not figure out what was wrong with me after having blood test after blood test done( I had symptoms of menangitus which was unheard of till a few years later after my recovery). As my family doctor could not find out what was wrong another doctor took over my case. What this other doctor found out from the test that he had taken was that my iron levels had fallen in which my dad was advised at the time to give me plenty of food that contained iron. However my dad did not do this which caused me 13 years of problems. Symptoms........................ Heavy headed ( like you havent slept) Physically could not get out of bed Extreme exhustion Confusion Poor short term memory Feeling spaced out all the time Not being fully aware of my surroundings..someone could call my name and I could not hear them. When people spoke to me I could not hear them and had to have them repeat everything..much to my mangers annoyance. Toward the end I had a bad temper..and unpredictable moods. Pins and needles Pulputation in my heart Triggured me to grind my teeth at night Heart burn--caused by my body being under stress I went back and forth from the doctor who told me I was depressed without even taking a blood test..I freaked out and thought I would manage the problem myself by going to the gym without realising I was making myself even more ill. The exhustion was advised by the doctor caused by me going to the gym...The dazed feeling was caused by me not wearing glasses. The pins and needles was due to my posture I took iron tablets and all these symptoms went over night (doctor did not diagnose this..my sister who took the iron tablets by chance kept on telling me how great she felt..so I took them. Needless to say have not felt this good in 13 years!!!!!!!!!!!!!!!!!.