In Psychological Medicine Thomas Wolfers and André Marquand showed that the average patient with ADHD does not exist biologically.Biological psychiatry heavily relies on so called case-control comparisons. In this approach a group of patients with for instance ADHD is compared against a group of healthy individuals on a number of biological variables. If significant group effects are observed those are related to for instance the diagnosis ADHD. This often results in statements such as individuals with ADHD show differences in certain brain structures. The results of Andre Marquand and Thomas Wolfers their work are in line with those earlier detected group effects, they clearly show that a simple comparison of these effects disguises individual differences between patients with the same mental disorder. In order to show this, they developed a technique called ‘normative modelling’ which allows s to map the brain of each individual patient against prototypical development. In this way they show that individual differences in brain structure across individuals with ADHD are far greater than previously anticipated. In future, this approach can provide important insights and sound evidence for an individualized approach to mental healthcare for ADHD and other mental disorders.
Individual differences v. the average patient: mapping the heterogeneity in ADHD using normative models.