What is the network approach to psychopathology? 

The network approach to psychopathology, first put forward in 2008, refers to the theory that mental illnesses can be thought of as causal systems consisting of symptoms, rather than a group of unrelated symptoms that are all caused by one underlying factor. This theory posits that symptoms may present themselves as syndromes because there are causal relationships between the symptoms themselves. In other words, these symptoms strongly and actively affect one another — they are not merely signs pointing to an illness. Symptoms are agents in a network, and their individual roles can change based on their centrality to the network. It has been shown via network studies that different symptoms within one psychopathology are highly connected. Even after controlling for shared variance between symptoms, the symptoms are very interconnected. This may suggest that the clustering of symptoms within separate mental disorders is meaningful. This inter-symptom connectivity has been shown to be stable over time and in various demographic groups. 

What is the connectivity hypothesis? 

The connectivity hypothesis is the theory that activation of psychological symptoms can spread through a highly connected symptom network. This hypothesis has been verified by research which illustrates that the activation (by an external trigger) of certain symptoms can set off activation of other symptoms. As time passes, strong inter-symptom relationships often grow stronger, and elevated symptom activation is maintained. Therefore, the state of the mental disorder is conceptualized as the strength of the relationships between symptoms and how they affect one another. Some researchers have posited that the more connected a person’s network of symptoms is, the more at risk one is for severe psychopathology. For example, they have found that there is greater network connectivity in people with persistent depression than in people with remitted depression. 

What should be the focus of future network approach research? 

Although there are many varying forms of the network approach and there has been much research on the topic recently, there is still very little information on how any specific disorder’s symptoms operate causally. To get to that point in the research, scientists must use computational models. These computational models should be utilizing assumptions that align with each specific disorder. It is important that large amounts of data are collected and pooled together to collect evidence and gain a comprehensive understanding of how causal systems of symptoms operate within different psychopathologies.