As from the above description of symptoms, ADHD has many similar (but different) symptoms to more well-known psychiatric disorders and so it is not surprising that the condition has often been missed or misdiagnosed by previous psychiatrists, who are not familiar with the condition. This is really important as there is effective medication available for the treatment of ADHD which is specific to the diagnosis, so failure to diagnose the condition results in failing a person diagnosed with the condition to receive appropriate treatment. 

The NICE guidelines state that for children with ADHD, behavioural and social treatments should be first-line choice in treatment and only if these fail, should medication be tried. However, for adults with ADHD, medication is first-line treatment, and amongst the different medications available, stimulant medication, such as methylphenidate or amphetamine is preferred. In a meta-analysis of all the medications available, lisdexamfetamine (which is amphetamine covalently bonded to an inert amino acid, to allow slow released in the stomach) has been found to be the most effective medication for adults.