Generalized anxiety disorder (GAD) is a mental illness marked by excessive, uncontrolled concern, as well as cognitive and emotional impairments, such as a tendency to overinterpret potential danger (IB). The purpose of this project is to: Adults with generalised anxiety disorder (GAD) were recruited for this research, which evaluated cognitive impairments, serum cortisol levels, and serum BDNF levels. Methods and subjects: 80 patients from the outpatient clinic of the psychiatric department at BENHA university hospital were selected for this cross-sectional research, and 80 healthy people with similar age, gender, and educational level were compared to the patient group. BDNF was shown to have a substantial association with illness duration and the Hamilton Anxiety Rating Scale (HARS). Stroop test and cortisol levels showed a substantial positive connection. This study implies that top-down control mechanisms favour anxiety reduction above task performance, as GAD patients have difficulty disengaging from danger while still participating in complex WM activities. Brain-derived neurotrophic factor (BDNF), task performance, and cortisol are all terms associated with GAD.