Conditions and Diseases that Mimic and Overlap Childhood ADHD
Many psychiatric conditions — including anxiety, depression, substance abuse, and personality disorders — mimic or mask the symptoms of ADHD. Sometimes it's hard for a medical expert to know which disease or condition is causing which symptoms and how to best treat it.
A high percentage of children with ADHD also suffer from the comorbid disorders that commonly occur alongside ADHD, and which may exacerbate a physician's attempt to isolate and treat symptoms.
The most common overlapping diseases and conditions include clinical depression and anxiety, bipolar disorder, substance abuse, alcoholism, learning disorders, dyslexia, brain injuries, dementia, psychosis, hypothyroidism, hyperthyroidism, conduct disorder, speech and communication problems, sensory integration disorders, oppositional defiant disorder, and sleep disorders.
Depression
Research shows that children with ADHD have three times the risk as the general population of suffering from major depression, and more than seven times the risk of suffering from dysthymia, or chronic low-level depression — the “never really happy” depression sometimes portrayed by comedian Woody Allen.
Researchers believe depression is more common among children with ADHD because the same neurobiological systems in the brain that control mood also control attention.
Another prominent theory holds that the relationship between ADHD and depression may result from the social and interpersonal difficulties experienced by many children with the disorder.
Fact
While no one is sure why children with ADHD tend to be moody, grumpy, depressed, and pessimistic, scientists today believe the ADHD “downer personality” may be the result of neurological dysfunctions in the brain combined with a patient's emotional response to repeated failure, frustration, and disappointment in his life.
It takes a real pro — and often, many diagnostic tests — to differentiate between depression and ADHD. Both disorders are marked by moodiness, forgetfulness, an inability to pay attention, a lack of motivation, and feelings of helplessness and hopelessness. Complicating things is the fact that many medications used to treat childhood ADHD may also increase symptoms of depression.

