The neurobiological link between OCD and ADHD

Abstract

Obsessive compulsive disorder (OCD) and attention deficit hyperactivity disorder (ADHD) are two of the most common neuropsychiatric diseases in paediatric populations. The high comorbidity of ADHD and OCD with each other, especially of ADHD in paediatric OCD, is well described. OCD and ADHD often follow a chronic course with persistent rates of at least 40–50 %. Family studies showed high heritability in ADHD and OCD, and some genetic findings showed similar variants for both disorders of the same pathogenetic mechanisms, whereas other genetic findings may differentiate between ADHD and OCD. Neuropsychological and neuroimaging studies suggest that partly similar executive functions are affected in both disorders. The deficits in the corresponding brain networks may be responsible for the perseverative, compulsive symptoms in OCD but also for the disinhibited and impulsive symptoms characterizing ADHD. This article reviews the current literature of neuroimaging, neurochemical circuitry, neuropsychological and genetic findings considering similarities as well as differences between OCD and ADHD.

Imaging genetics in obsessive-compulsive disorder: Linking genetic variations to alterations in neuroimaging

“…a Findings of significant or nominal association with OCD. association between OCD and dopaminergic genes -such as the DAT1 VNTR gene variant -could be confirmed and only very small effect sizes have been shown for DAT1 in OCD so far (see review Brem et al, 2014). Atmaca et al (2010) recently published a study that combined magnetic resonance imaging measurements with analysis of the myelin oligodendrocyte glycoprotein (MOG) gene polymorphism, which was of interest in the context of OCD because of the positive results of a family-based association study (Zai et al, 2004).…”

Network analysis of specific psychopathology and psychiatric symptoms in patients with eating disorders

“…Notwithstanding the need to formulate clear diagnoses each with a range of possible treatment, a growing literature summarizes the limitations of the use of a categorical approach in psychiatry (Maj, ). For example, boundaries across disorders are not as clear as DSM is proposing, and, in many cases, it is possible that a diagnostic category encompasses a large number of different neurobiological entities (Brem, Grunblatt, Drechsler, Riederer, & Walitza, ; Dacquino, De Rossi, & Spalletta, ; Goodkind et al, ). The dimensional approach recommended by the Research Domain Criteria (RDoC) is one of the proposed alternative models, although other approaches are being considered by the literature in the field (Boschloo et al, ; Fried et al, ).…”

Treatment Efficacy of Combined Sertraline and Guanfacine in Comorbid Obsessive–Compulsive Disorder and Attention Deficit/Hyperactivity Disorder: Two Case Studies

“…22–26 Brem and colleagues 27 suggest that though OCD and ADHD symptoms appear to be antipodes, their frequent comorbidity likely stems from both being the result of abnormal inhibitory processes. Although pharmacologic treatments for OCD may work by normalizing cortical glutamatergic activity, resulting in decreased attention to detail, decreased interest in planning, desire to “live in the present”, and increased dependence on exteroceptive stimulation, 19 the positive resolution of OCD symptoms potentially may promote symptoms that mimic ADHD.…”