Stress (specifically elevated levels of circulating corticosteroids) has been associated with the cognitive deficits seen in human aging. Many studies show that stress and fatigue negatively impact cognitive functioning in young adults. Some level of stress in the learning environment may aid the ability to focus and retain information. However, stress levels, especially high, sustained or traumatic stressors, hinder declarative memory, spatial reasoning, learning, attention and working memory. Fatigue is also a stressor that impedes attention, processing, retrieval, working memory and short term memory. The effects of stress on cognitive performance seem to be controlled by the sympatho-adrenal system and the hypothalamic-hypophysial-adrenal axis.
Depression and depressed mood negatively affect cognitive performance and memory. Depression was found to increase false memory, especially with negative words or subjects.
It is reasoned that counteracting and preventing depression and stress management may be an effective nootropic strategy. Proper nutrition, adequate sleep, and mechanisms for coping with stress, such as meditation, have been shown to improve learning and cognitive functioning both
in the short and long term.