**2.4 Animal models in attention-deficit/hyperactivity disorder (ADHD)**

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder, affecting approximately 2.2–2.8% of worldwide, with multifactorial inducement, as reflected by the heterogeneity found in this disorder, and as indicated by the diversity in its psychiatric comorbidities [97]. This disorder is defined by inappropriate levels of attention deficits and/or hyperactivity behavior, which directly interfere with the normal life and functioning of an individual [98]. While there is no cure for ADHD, currently available treatments can help reducing the symptoms and improving the general functioning, although with a peculiar wide variability due to the clinically and scientifically difficulties to exactly determine the specificity and the origin of the symptoms [99]. As for other PDs, due to the high heritability, animal models for ADHD are mostly derived from genetic alterations or breeding selection or from neonatal insults that can lead to neurodevelopmental changes. Models related to dopaminergic neurotransmission are also important to evaluate ADHD, as also listed in **Table 2**, and which includes the administration of psychostimulants as amphetamine. A more detailed review on ADHD animal models can be found elsewhere [100] (**Table 5**).


## **Table 5.**

*Examples of models for ADHD induced by genetic manipulation in susceptibility genes and selective inbreeding and by prenatal insults.*
