Brain fog is characterized by a lack of focus and mental clarity, forgetfulness, and confusion. This can be caused by lack of sleep, stress, overworking, and spending too much time on the computer. On a scientific level, brain fog is presumed to be caused by high levels of inflammation, and changes to hormones that determine your mood, energy, and focus. The imbalanced levels of hormones can make the whole system confused. Brain fog is a syndrome that can lead to other conditions such as abnormal menstruation, obesity, and diabetes mellitus.