Attention to Dopamine – ADHD project

​Several commonalities exist between patients with Attention Deficit Hyperactivity Disorder (ADHD) and patients with schizophrenia. This study aims at comparing psychophysiological parameters of basic information processing and cognition in both patients with ADHD and schizophrenia.

Both patients with ADHD and schizophrenia show attentional deficits. Furthermore, patients with schizophrenia often report a history of (premorbid) ADHD symptoms. The commonality between the diseases is further supported by the notion that ADHD is frequently found in children at genetic risk for schizophrenia.

Whilst prototypical cases of ADHD and schizophrenia are readily distinguishable from each other, it can be difficult for a clinician to distinguish the thought disorders and hallucinations often found in schizophrenia from the perceptual abnormalities and executive deficits commonly seen in patients with ADHD.

Despite the similarities and overlap, the two diseases are treated with medication with largely opposite effects on central neurotransmitter systems. ADHD is predominantly treated with methylphenidate which, among other effects increases levels of dopamine in the brain, whilst the dominant treatment in schizophrenia is focused on reducing dopaminergic activity in the brain by blocking dopaminergic D2 receptors with antipsychotics.

In the current study we aim to compare psychophysiological parameters of basic information processing and cognition in both patients with ADHD and schizophrenia, with a focus on dopaminergic neurotransmission. The study is designed as a prospective six week follow-up study with 50 medication naïve adult patients with ADHD, and 55 healthy controls matched on age, sex, ethnicity and parental socioeconomic status. The schizophrenia patients included in the study will be recruited as part of the PECANS II study.

Patients will first be assessed in the medication-naïve state, and again following a six-week period of medical treatment. During this period, patients with ADHD will be treated with methylphenidate, while patients with schizophrenia will be treated with aripiprazole (a partial dopamine D2 receptor agonist).


PhD theses based on data from this cohort:

  • Julijana Le Sommer "Psychophysiological profiling of attentional deficits in medication naïve patients with ADHD or schizophrenia before and after their first medication" (expected 2017)
  • Ann-Marie Low "Cognitive Functioning in Adults with ADHD: Visual Attention and Impulsivity" (expected 2017)