Background: Neuropsychological deficits have been reported in patients with Major Depressive Disorder (MDD) during an acute episode. The reaction time gives an idea about integrity and the processing ability of central nervous system. The simple reaction time task is an attention seeking task that focuses primarily on speed of processing (executive function). Psychomotor retardation (i.e., delay at the output which includes perceptual decision, planning, motor process) is a constant and probably central feature of depression.
Aims: The purpose of present study was to evaluate the neuropsychological functioning in young non-hospitalised un-medicated non-psychotic unipolar depression by focusing on tasks related to prefrontal cortex functioning.
Materials and methods: Newly diagnosed young antidepressant-free, clinically depressed patients (20 males and 24 females, n=44) and healthy controls (24 males and 27 females, n=51) pair-wise matched on gender, age (mean age 25±4) were included in this study. All patients were diagnosed with major depressive episode according to Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Both the patients and healthy controls performed a simple reaction time task with components of alerting auditory and visual orientation of attention by an instrument response analyzer. Statistical Analysis : The performances were expressed in mean ± standard deviation of the reaction time by using the Student's unpaired t-test.
Results: Patients with unipolar depression relative to controls were impaired on psychomotor performance and deficits in sustained attention remained significant.
Conclusions: These findings suggest deficits in sustained attention as vulnerability marker for unipolar depression. With further methodologically sound research, the changes in neuropsychological function associated with treatment response may provide a means of evaluating different treatment strategies in major depression.
Keywords: Attention deficits; Dorsolateral prefrontal cortex; Executive dysfunction; Psychomotor retardation; Simple reaction time; Unipolar depression.