As in children and adolescents, medicinal treatment is the first choice in the treatment of adult Attention Deficit Hyperactivity Disorder (ADHD). However, in adults, the rate of success of medicinal treatment is 50% or less. The reason for this is that whilst medicinal treatment is effective for main symptoms (attention deficit, restlessness, impulsivity), it is not very effective for functional symptoms (time management, organization, planning etc.). For the same reason, the rate of continuation of treatment is also lower for adults. The patient who thinks that treatment is not delivering the expected results will not continue treatment. To prevent this, before commencing with medicinal treatment, the symptoms for which the treatment may be effective are described and possible treatment methods for other issues are explained. Another reason for the decrease of patients’ compliance with treatment is the symptoms of the illness itself, such as lack of concentration, forgetfulness. Because of their habits, groups who suffer from more substantial attention deficit, obtain less benefit from medicines. In adult patients, other treatments are therefore applied besides medicinal treatment. These other treatments may be listed as follows: psychotherapy, cognitive behavioral treatment, family treatment, consultancy on the issue of Attention Deficit Hyperactivity Disorder, education oriented on self control. For the large part of patients, treatment of adult Attention Deficit Hyperactivity Disorder is started with stimulants or Atomoxetine. If there is no response through the appropriate dose of medicine, a different medicine is tried. In the event of cardiac side-effects, tic disorders, mood dysregulation, medicine is not continued. For some side-effects, the decrease of dosage of medicine or the addition of other medicine will solve the problem. If the problem is not resolved despite this, another group of medicines will be reverted to. Despite all available medicines, some patients will not respond to treatment or symptoms will worsen. It is necessary in such situations to alter the dosage of medicine. Depending on the condition of the patient and the symptoms, the dosage will either be decreased or increased. Another manner of changing effectiveness is the alteration of the moment of administration of medicine. If there is no improvement despite this, the most correct thing to do is to revert to another group of medicines and cognitive behavioral treatment, giving the patient individual, guiding, support. If side effects are the reason for the lack of effectiveness of treatment, the relation between these side effects and the medicine is evaluated. Sometimes, altering the moment of administration of medicine can decrease the side effects. If not, the medicine should be changed and therapies must be added. If symptoms reoccur during treatment, altering the moment of the administration of medicine, the frequency of the administration of medicine, may resolve the problem. If not, it is necessary to alter treatment. In approximately one fourth of adult Attention Deficit Hyperactivity Disorder patients, one or more additional disorders are manifest. Anxiety disorders, depression and anti-social personality disorders are most frequently to be seen. In treatment, the response to stimulants is good. In about only 30% of patients is an adequate response not achieved or is no use made because of side effects. If serious mental problems arise during treatment, irrespective of the medicine, the effectiveness of treatment will decrease. In these situations, a careful evaluation must be made as to whether or not an additional disorder is manifest. Because if the problem is related to the other illness, the alteration of the dose of medicine or the medicine will not resolve the problem. Two important groups are to be observed in relation to the medicinal treatment of adult ADHD patients. The first group is the group, which encounters difficulties in treatment because of additional disorders, intolerable side effects; the other is the group, which shows no response to any medicinal treatment. The resistant group which does not respond to treatment more often regards patients who have other mental problems besides ADHD. In these situations, with the discontinuation of medicine, the application of other treatments comes to the fore. Furthermore, problems in the cure of functionally oriented symptoms, despite the cure of main symptoms in those who benefit from treatment, are also a reality. For this reason, in the treatment of adult ADHD, extra-medicinal treatments become more important. Cognitive behavioral therapy, individual therapy support and giving guidance to the patient with regards to ADHD are the most applied and advised psychological treatment methods.