The three primary symptoms of attention deficit disorder are inattention, impulsivity and hyperactivity, according to Psych Central. These can often manifest more subtly as procrastination and irritability.
ADD can be difficult to diagnose because the symptoms can manifest in different ways for different people. For example, while being easily distracted is a common symptom, some people also hyperfocus, explains Healthline. This means that they focus so heavily on something that they lose track of time and their surroundings. This can cause chronic lateness and trouble meeting deadlines.
Forgetfulness is a common symptom of ADD in adults, according to Healthline. Although everyone is forgetful sometimes, people with ADD may have unusual trouble remembering even major things. They may chronically misplace objects and forget important dates.
Children often suffer from hyperactivity as part of ADD, according to Psych Central. They may have trouble sitting still for classes and may be disruptive even while playing with other children. They often fidget and talk constantly or make other loud noises at inappropriate times. Adults may also display inappropriate social behaviors such as interrupting others.
Other emotional problems are common side effects of ADD, explains Healthline. Depression and mood swings are commonly found in people with ADD due to boredom and frustration. Marital or other relationship problems are also common side effects of ADD symptoms, reports WebMD.