ADHD (Attention Deficit Hyperactivity Disorder) is a complex pathological condition analysed mainly in children. In fact, ADHD in adults presents a more heterogeneous pattern of symptoms. Additionally, possible associated comorbidities can contribute to make the correct diagnosis in adults even more difficult. On top of the abovementioned complexity, coexistence of pathologies like ADHD and Obsessive Compulsive Disorder (OCD) appears to be not thoroughly investigated in adult population.

In this regard, we present a case of a woman with OCD characterized by doubtful obsessions, accumulation compulsions, attention difficulties and deficit in executive functions. In particular, we aim to describe both the peculiarities of each disorder and the overlapping aspects between inattentive ADHD and OCD in adults. A good knowledge of the psychopathology of these two disorders is fundamental for differential diagnosis and exclusion of false comorbidity