AD/HD can be difficult to spot at times; particularly when there are other mental health symptoms that are viewed as priority.  Careful screening should be undertaken in order to determine the most accurate diagnosis.  It is not uncommon for AD/HD patients to have been treated for the following prior to undergoing through assessment and beginning treatment for AD/HD:

Major Depressive Disorder: It is important to remember that frustration related to longstanding struggles with ADHD does not necessarily mean clinical depression.  Patients may present with symptoms of depression but, underlying these mood difficulties can be a history of untreated AD/HD.  These untreated symptoms may have led to decreased self-esteem, poor school and work performance, or feelings of inferiority, all of which can create and intensify depressive symptoms.  Although this depression is very real, it may be secondary to the AD/HD diagnosis, and may go away once the AD/HD is successfully treated.