Inhibition Impairment in Depression

Proposal details

Title: Inhibition Impairment in Depression
Research Area(s): Emotion and Self Regulation
Brain Imaging
Depression
Genetics
Individual Differences
Background: Cognitive biases in depression are characterized as follows: 1) depressed individuals exhibit cognitive biases in all aspects of information processing, including memory, interpretation, and perception and attention; 2) depressed individuals have the ability to perform cognitive tasks at the level of nondepressed people in structured situations but have problems doing this on their own initiative in unconstrained situations; 3) depressed individuals do not direct their attention to negative information more frequently than do control participants, selective attention only under conditions of long stimuli exposures; and 4) once negative material captures their attention, depressed individuals exhibit difficulties disengaging from it. Therefore, depression is not necessarily characterized by a general cognitive deficit or by a high level of alertness in the processing of negative material. However, once negative material has become the focus of attention, depressed individuals are prone to elaborate on it and have difficulty stopping or inhibiting the processing of this material. This specific difficulty in processing negative information is likely to have important consequences for depressed people’s ability to recover from negative affect and, consequently, may represent an important link between cognition and emotion dysregulation in this disorder. Therefore, inhibitory impairment is not simply a symptom of depression or a scar of a previous depressive episode, but may play an important role in the vulnerability to depression. In addition, depression is one of the most commonly occurring disorders in PTSD. It has been found that among people who have or have had a diagnosis of PTSD, approximately 48% had current or past depression. Depression and anxiety disorders also co-occur often. People with depression often experience symptoms similar to those of an anxiety disorder, such as nervousness, irritability, and problems sleeping and concentrating. Many people who develop depression have a history of an anxiety disorder earlier in life.
Aims: #1: the impaired inhibition can be shown in EEG components when depressed individuals are presented negative stimuli. #2: the impaired inhibition is assoicated with the reduced connectivity between brain regions. #3: in patients with PTSD or anxiety disorder, individuals with high depression level will show the same inhibition impairment, as reflected by EEG measurement.
Method: Depressed individuals will be compared to normal control on cognitive and EEG measures. Brain structures will be compared as well. EEG data and cognitive data will be analyzed with different computer programs and correlated to clinical symptoms.