Autism/Aspergers syndrome

Those with autism seem to have a difficult time emotionally connecting to others, and can behave awkwardly in social situations. Those with autism can also get overly anxious in busy or loud places, which can look like hyperactivity. All these symptoms are also a part of ADHD, and can lead doctors to overlook the possibility of the other conditions.

Hearing impairments

People who don’t have 100 percent of their hearing can act awkwardly in social situations, and as a result of that may have stunted communication skills. Since they don’t hear when they do listen, this often deters them from paying attention. All of this can cause them to miss details, which can look like ADHD.

Hypothyroidism

Hypothyroidism can lead to feelings of depression, difficulty concentrating and lapses in memory. ADHD also manifests itself through an inability to concentrate and forgetfulness.

Iron deficiency anemia

People with iron deficiencies can struggle with chronic exhaustion plus irritability. In children, such a deficiency can lead to a struggle to concentrate, impaired cognitive skills and a short attention span, all of which are symptoms displayed by those with ADHD.

Lead toxicity

Even a mild case of lead poisoning can lead to large problems like decreased school performance, short-term memory problems, decreased cognitive function and even mental retardation. Children with ADHD can also display these symptoms.

Mental retardation

Mental retardation in children can easily be mistaken for emotional immaturity, especially since children mature at such different rates. Children with the condition display limited social skills and trouble in school and often require extra time to learn new concepts. Symptoms also include forgetfulness and an inability to understand cause and effect.

Nutritional deficiencies/food allergies

Children who are hypoglycemic display several symptoms also found in those with ADHD, like aggression, hyperactivity, restlessness and difficulty concentrating. Even if a child does not suffer from low blood sugar, he could have a reaction to certain food chemicals like MSG, red dye, corn syrup and other additives. These reactions can result in anger, agitation, impulsiveness, hyperactivity and difficulty concentrating.

Seizure disorders

Children who suffer from mild seizures can experience seizures that are so brief—lasting only seconds—they go unnoticed. However, after a seizure a child can be disoriented and confused, which in turn makes it difficult to pay attention or follow instructions, which can be mistaken for ADHD.

Sensory disorders

Children with sensory disorders often take risks without realizing the dangers involved, jumping rapidly from one activity to another. They can be accident-prone. All are associated with ADHD.

Sleep disorders

If a child is regularly sleep deprived, this can cause her to have a hard time concentrating, communicating, following directions and recalling information. Some with ADHD are known to have sleep disorders, but the reverse is not necessarily true.