Neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are considered mental disorders: Diagnostic manuals such as the DSM-5 define them by behavioral characteristics and by the impact of those characteristics on daily-life functioning. Because of their high heritability, ASD and ADHD are also considered genetic and neurobiological conditions. As a result, the vast majority of research is trying to explain their genetic and neurocognitive etiology. However, using simple genetic models or a unified neurocognitive explanatory model, no one has been able to carve the neurodevelopmental disorders at their natural joints (Waterhouse et al. Reference Waterhouse, London and Gillberg2016). As such, they are exemplars of the thesis of Borsboom et al. that “findings [regarding the biology of mental disorders] have not been translated into convincing reductive explanations of mental disorders through central pathogenic pathways rooted in neurobiology, as many had expected” (target article, sect. 1, para. 3).
By looking at co-occurring symptoms and their relationships, instead of trying to find a common underlying cause, the network perspective also acknowledges that diagnostic boundaries are not always clear and that behavioral symptoms commonly co-occur. Hereby the approach gives place to a trans-diagnostic and more dimensional perspective, instead of the purely categorical approach. Moreover, applying a network approach to neurodevelopmental disorders not only challenges current reductionist approaches, but at the same time also offers a research strategy that does not deny the realness of the lived experience. For example, the network approach incorporates cultural and environmental contexts. Indeed, when we look at the conceptualization of autism through history, a shift can be noted of the behaviors that are considered “autistic,” and this probably also differs in different cultural contexts (Kim Reference Kim2012). Also, new approaches such as enactivism and discoveries regarding epigenetics suggest that a conception of neurodevelopmental disorders as challenges that can be attributed solely to a malfunctioning in the individual is wrong because they also depend on their cultural and environmental context (De Jaegher Reference De Jaegher2013). The network approach also stresses the importance of intentional information – information about mental states – as conveyed by those with the disorder. This leads to a better Verstehen of what it means to have the disorder. Especially in specific types of research into the origins of neurodevelopmental disorders, the latter has been completely ignored. One only needs to look at the many mouse models for ASD or ADHD for examples of how the actual meaning of experience has often been neglected in favor of reductionist and mechanistic explanations.
We also pinpoint a challenge that may hamper a successful implementation of a network approach to the neurodevelopmental disorders: The symptoms that are historically associated with these disorders, and that are used as diagnostic criteria, may not fully grasp what is to be considered ASD or ADHD. In a network approach, symptoms do not co-occur because they are symptoms of a common underlying disorder, but because they directly influence each other. As an illustration, for ASD, one could say that the preference for repetitive behavior influences social interaction, and vice versa. Or for ADHD, being inattentive and being hyperactive may influence each another without being caused by one underlying condition that is ADHD. Although similar problems exist for mood disorders such as depression, especially with regard to neurodevelopmental disorders, the network approach will have to deal with a certain circularity: “I am hyperactive; therefore, I get a diagnosis of ADHD”; “I have ADHD; therefore, I am hyperactive.” This circularity suggests that, for many people diagnosed with a neurodevelopmental disorder, the symptoms used for diagnosis do not completely grasp or coincide with what they experience as being at the core of their disorder, and this mismatch or gap may be larger in neurodevelopmental disorders than in other mental disorders. Indeed, in recent years, we have seen an explosion of autobiographical accounts by persons with neurodevelopmental disorders. In these, it is often claimed that the way these disorders are defined, and the behavioral characteristics that define them, are not accurate descriptions of what it actually means to have such a disorder. Some individuals with a diagnosis of ASD may claim that they are not socially challenged but instead have a misaligned reaction time. In order to come up with a socially adequate response, they need more than the standard window of opportunity for an appropriate social response. In the context of adult women with ASD, it is often claimed that they do not exhibit the standard behavioral characteristics, and that their autism is more difficult to grasp in DSM terms (see Mandy & Lai [Reference Mandy and Lai2017] for a special issue on female ASD). Hence, we believe that in the case of neurodevelopmental disorders, it will be of utmost importance to correctly define the different nodes of the network used to conceptualize them. This task will have to be done on the basis of phenomenological studies of what it means to have a neurodevelopmental disorder. Moreover, especially in the case of ASD, it will be difficult to relate different symptoms with one another without committing to an explanatory theory. Such theory may in itself be too reductionist or not reflect the experience of those diagnosed. For example, can we consider social challenges and challenges with regard to information processing as separate nodes in the network that influence each other? Or, do we regard social challenges as a result of challenges in information processing, or vice versa? Depending on the explanatory model that is taken as a basis, the network will look entirely different. In trying to approach neurodevelopmental disorders as networks of symptoms, perhaps such disorders will turn out to be too heterogeneous even to be captured in this way.
Neurodevelopmental disorders such as autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) are considered mental disorders: Diagnostic manuals such as the DSM-5 define them by behavioral characteristics and by the impact of those characteristics on daily-life functioning. Because of their high heritability, ASD and ADHD are also considered genetic and neurobiological conditions. As a result, the vast majority of research is trying to explain their genetic and neurocognitive etiology. However, using simple genetic models or a unified neurocognitive explanatory model, no one has been able to carve the neurodevelopmental disorders at their natural joints (Waterhouse et al. Reference Waterhouse, London and Gillberg2016). As such, they are exemplars of the thesis of Borsboom et al. that “findings [regarding the biology of mental disorders] have not been translated into convincing reductive explanations of mental disorders through central pathogenic pathways rooted in neurobiology, as many had expected” (target article, sect. 1, para. 3).
By looking at co-occurring symptoms and their relationships, instead of trying to find a common underlying cause, the network perspective also acknowledges that diagnostic boundaries are not always clear and that behavioral symptoms commonly co-occur. Hereby the approach gives place to a trans-diagnostic and more dimensional perspective, instead of the purely categorical approach. Moreover, applying a network approach to neurodevelopmental disorders not only challenges current reductionist approaches, but at the same time also offers a research strategy that does not deny the realness of the lived experience. For example, the network approach incorporates cultural and environmental contexts. Indeed, when we look at the conceptualization of autism through history, a shift can be noted of the behaviors that are considered “autistic,” and this probably also differs in different cultural contexts (Kim Reference Kim2012). Also, new approaches such as enactivism and discoveries regarding epigenetics suggest that a conception of neurodevelopmental disorders as challenges that can be attributed solely to a malfunctioning in the individual is wrong because they also depend on their cultural and environmental context (De Jaegher Reference De Jaegher2013). The network approach also stresses the importance of intentional information – information about mental states – as conveyed by those with the disorder. This leads to a better Verstehen of what it means to have the disorder. Especially in specific types of research into the origins of neurodevelopmental disorders, the latter has been completely ignored. One only needs to look at the many mouse models for ASD or ADHD for examples of how the actual meaning of experience has often been neglected in favor of reductionist and mechanistic explanations.
We also pinpoint a challenge that may hamper a successful implementation of a network approach to the neurodevelopmental disorders: The symptoms that are historically associated with these disorders, and that are used as diagnostic criteria, may not fully grasp what is to be considered ASD or ADHD. In a network approach, symptoms do not co-occur because they are symptoms of a common underlying disorder, but because they directly influence each other. As an illustration, for ASD, one could say that the preference for repetitive behavior influences social interaction, and vice versa. Or for ADHD, being inattentive and being hyperactive may influence each another without being caused by one underlying condition that is ADHD. Although similar problems exist for mood disorders such as depression, especially with regard to neurodevelopmental disorders, the network approach will have to deal with a certain circularity: “I am hyperactive; therefore, I get a diagnosis of ADHD”; “I have ADHD; therefore, I am hyperactive.” This circularity suggests that, for many people diagnosed with a neurodevelopmental disorder, the symptoms used for diagnosis do not completely grasp or coincide with what they experience as being at the core of their disorder, and this mismatch or gap may be larger in neurodevelopmental disorders than in other mental disorders. Indeed, in recent years, we have seen an explosion of autobiographical accounts by persons with neurodevelopmental disorders. In these, it is often claimed that the way these disorders are defined, and the behavioral characteristics that define them, are not accurate descriptions of what it actually means to have such a disorder. Some individuals with a diagnosis of ASD may claim that they are not socially challenged but instead have a misaligned reaction time. In order to come up with a socially adequate response, they need more than the standard window of opportunity for an appropriate social response. In the context of adult women with ASD, it is often claimed that they do not exhibit the standard behavioral characteristics, and that their autism is more difficult to grasp in DSM terms (see Mandy & Lai [Reference Mandy and Lai2017] for a special issue on female ASD). Hence, we believe that in the case of neurodevelopmental disorders, it will be of utmost importance to correctly define the different nodes of the network used to conceptualize them. This task will have to be done on the basis of phenomenological studies of what it means to have a neurodevelopmental disorder. Moreover, especially in the case of ASD, it will be difficult to relate different symptoms with one another without committing to an explanatory theory. Such theory may in itself be too reductionist or not reflect the experience of those diagnosed. For example, can we consider social challenges and challenges with regard to information processing as separate nodes in the network that influence each other? Or, do we regard social challenges as a result of challenges in information processing, or vice versa? Depending on the explanatory model that is taken as a basis, the network will look entirely different. In trying to approach neurodevelopmental disorders as networks of symptoms, perhaps such disorders will turn out to be too heterogeneous even to be captured in this way.