PET Scan Gallery
The PET scan ( Positron Emission Tonometry) evaluates the amount of brain activity, making it an invaluable tool in diagnosing depression. A depressed brain’s activity is diminished, much like being in a state of hibernation.
Red indicates the most activity in the brain, followed by yellow, green and blue. The more blue in evidence, the more depressed an individual.
Antidepressents traditionally can change affect within two weeks, changes in brain intensity is not evident on a PET scan for three to four months.
PET scans are not yet used as a diangostic tool for depression. Rather, the patient is evaluated to rule out other possiblities for the mood disorder and then is treated with anti-depressants until the symptoms subside. Often, this involves weaning on and off several medicines as well as creating a pharmacological cocktail of medications to mask side effects and/or deal with aspects of the illness not addressed by the chosen drug.
The Diagnostic and Statistical Manual for Psychiatric Disorders, Fourth Edition, Text Revision (DSM-IV-TR), the diagnostic Bible put out by the American Psychiatric Association, in its criteria for major depression lists EITHER feeling depressed most of the time for two weeks OR abnormal loss of interest or pleasure most of the time for two weeks. This dichotomy effectively divides depression into an either-or choice of exaggerated sadness on one hand or lack of emotion on the other. link.
The Hamilton Depression Scale is the test traditionally used to determine a diagnsosis of depression.
1. Depressed mood most of the day (nearly everyday)
2. Markedly diminished interest in daily activities
3. Significant weight loss or gain
4. Insomnia or excessive sleeping.
5. Agitation or slowing of purposeful movements
6. Fatigue-probably the most common symptom of depression
7. Feelings of worthlessness
8. Diminished ability to think
9. Recurrent thoughts of death
10. Reduced sex drive
11. Inability to enjoy activities that have always been fun in the past