The long way to diagnosis: attention disorder, alcohol addiction or congenital disorder of glycosylation? A case report.

Attention deficit hyperactivity disorder (ADHD) is a relatively common disorder in clinical psychiatry. Patients often suffer from symptoms long before the diagnosis due to an overlap with other psychiatric differential diagnosis. Importantly, alcohol addiction and other illicit drug dependence and withdrawal symptoms mimicking ADHD symptoms should be ruled out. Here we present a rare case of a young female patient with symptoms of ADHD and an extremely high carbohydrate-deficient transferrin (CDT) of 19,6% (< 1,3%) indicating the presence of a congenital disorder of glycosylation (CDG). A thorough diagnostic workup excluded alcohol addiction as a cause of the constantly high CDT levels. The CDT test was positive due a transferrin mutation affecting the glycosylation site. Nevertheless, psychiatric symptoms can be due to metabolic disorders which should be considered. Further, substance-use disorders (SUD) are a critical and potentially complicated differential diagnosis concerning diagnostic procedures and treatment in ADHD.