Brain Function in Mentally Ill Adolescents

Adults with post-traumatic stress disorder (PTSD) or major depressive disorder (MDD) exhibit abnormalities in the structure and function of the amygdala and hippocampus (temporal lobe), as well as in the prefrontal cortex (PFC) and striatum (four brain structures underlying the emotional processing and reward systems). However, while these psychiatric disorders often emerge in childhood, the integrity of these neural structures has been minimally studied in psychiatrically impaired children and adolescents. In the current proposal, functional MRI (fMRI) will be used to evaluate the amygdala, hippocampus, PFC and striatum in (1) psychiatrically healthy adolescents; (2) adolescents with trauma history and PTSD or anxiety symptoms; (3) adolescents with trauma history, symptoms of depression and either PTSD or anxiety symptoms; and (4) adolescents with only major depressive or PTSD/anxiety symptoms; (5) adolescents with trauma and no trauma related symptoms. The proposed study is conducted in three separate experiments.

At this stage of the protocol, we completed experiment 1, and a pilot study to help guide experiments 2 and 3. In Experiment 1, we determined whether a fear conditioning paradigm elicited amygdala activity in healthy adolescents. The pilot study examined test-retest reliability of the fMRI signal in healthy adolescents and adults.

In Experiment 2, we will examine the functioning of the amygdala, hippocampus, PFC and striatum in healthy adolescents and those with the psychiatric conditions described above. During image acquisition, four cognitive tasks, targeting these regions, will be used: 1) a social interaction task, 2) an inhibition task (the Stop task or the antisaccade task), 3) an emotional rating/explicit memory task and 4) a probe detection task. One hundred twenty five participants (25 in five groups) will be recruited in experiment 2.

Experiment 3 will address the same question as in experiment 2 in relation to treatment response. In other words, in contrast to experiment 2, patients will be studied prior and after treatment of the psychopathology associated with their traumatic experience. The sample will include 125 patients (25 in each of the 4 groups) and 25 controls.