Symptoms
can include:
Trouble concentrating, remembering details, and making decisions
Fatigue
Feelings of guilt, worthlessness, and helplessness
Pessimism and hopelessness
Insomnia, early-morning wakefulness, or sleeping too much
Irritability
Restlessness
Loss of interest in things once pleasurable, including sex
Overeating, or appetite loss
Aches, pains, headaches, or cramps that won't go away
Digestive problems that don't get better, even with treatment
Persistent sad, anxious, or "empty" feelings
Suicidal thoughts or attempts
Diagnosis
There isn't a "depression test" a doctor can use to see if you have it, so figuring that out often starts with a thorough history and physical exam.
Your doctor will want to know:
When your symptoms started
How long they've lasted
How severe they are
If depression or other mental illnesses run in your family
If you have a history of drug or alcohol abuse
You'll also be asked if you've had similar symptoms of depression before, and if so, how it was treated.
Treatment
If your doctor rules out a physical cause for your symptoms, he may start you on a treatment or refer you to a mental health professional. This specialist will figure out the best course of treatment. That may include medicines (such as antidepressants), a type of therapy called psychotherapy, or both.
I personaly think that animal therapy is possibly the most effective way to help people with depression.
I hope this helps :)