(dailyRx News) Some amount of angst, anxiety and occasional depression seems normal for most teenagers. However, up to 59 percent of depressed teens suffer from anhedonia, or the inability to experience pleasure.
While adolescent depression is complex and often intertwined with other disorders, and therefore hard to study, teens who seem unable to feel joy have lower levels of a certain brain chemical.
The neurotransmitter GABA is a major mood-regulating key in the brain, and teens with anhedonia have lower levels of GABA, according to findings from the National Institute of Mental Health. In a recent study, NIMH found that certain depressive symptoms, and the way in which they are measured, may offer new clues into the pathways and processes of depression and other mental disorders.
Vilma Gabbay, MD of New York University School of Medicine conducted research to focus on abnormalities in GABA production and function in the brain. These abnormalities have previously been linked to postpartum depression, schizophrenia and possibly learning disorders, as well as anhedonia.
Gabbay's team used a specialized type of MRI to measure the GABA levels in 20 teens with depression, half of whom were also diagnosed with anhedonia. Their MRIs were compared to 21 control subjects who did not suffer from either disorder. The teens with depression had significantly lower GABA levels, which were also associated with more severe anhedonia symptoms.
"Compared to traditional measures that categorize symptoms only as being either present or absent, such continuous or “dimensional” measurements may provide greater specificity to disease evaluations in research," NIMH stated.
Findings were published online in October 2011, in the Archives of General Psychiatry.