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The symptoms of mental disorders are directly related. In fact, these interactions actually cause people to develop a disorder. Angélique Cramer argues this theory in her doctoral thesis, which she will be defending at the University of Amsterdam (UvA) on Friday, 6 September. Cramer’s novel approach to mental disorders is diametrically opposed to the commonly accepted medical model. If widely accepted, her theory could have far-reaching implications in terms of diagnosis and treatment in clinical practice.

Her work casts doubt on the current medical model for mental disorders.  Cramer challenges the received view that the symptoms of a mental disorder such as major depression develop along the same lines as the symptoms of a medical illness such as lung cancer. For example, no single pathological condition has ever been unequivocally identified as the cause of depressive symptoms. In the case of lung cancer, however, a tumour clearly causes a series of identifiable symptoms such as weight loss and a persistent cough.

There are no direct relationships between the symptoms of medical conditions such as lung cancer. For example, weight loss does not cause a persistent cough or vice versa; the two symptoms are both caused by the tumour. According to Cramer, however, the symptoms of mental disorders are directly related. In fact, these interactions actually cause people to develop a disorder.  She illustrates this theory using two symptoms of depression: sleeplessness and fatigue. According to the medical model, major depression causes these symptoms.  However, one might justifiably ask: isn’t fatigue simply the effect of sleeplessness?

Network-based approach

Cramer presents a new network approach to mental disorders which, in her view, does more justice to the complex reality of mental disorders and personality traits. ‘Each individual has their own network of symptoms and it is reasonable to assume that these personal networks differ from one another’, Cramer explains. ‘Unlike our current approach based on the medical model, the network approach does not view the development of major depression as any one abnormality of the brain that causes the same symptoms in every person. On the contrary: according to the network approach, symptoms continue to ‘infect’ one another through direct interactions (for example: sleeplessness can result in fatigue and concentration problems at work, which then result in feelings of guilt about poor job performance, causing a sad mood and an inability to sleep at night). These direct interactions might plunge the patient into a vicious cycle, which cannot be broken without some (therapeutic) intervention.

Treatment implications 

Adopting the network approach to mental disorders could have far-reaching implications in terms of the way we diagnose and treat people in clinical practice. If no pathological condition – a common cause of the depressive symptoms – can be identified, treatment of this condition is relatively pointless. ‘In concrete terms, this would mean that prescription of an antidepressant (a drug designed to target a common cause – a serotonin deficiency) may not always be the most effective treatment option’, Cramer explains. ‘According to the network approach, it might be more effective to treat the individual symptoms and their respective interrelations. In the case of a patient with a strong connection between depressive feelings and the development of suicidal thoughts, treatment could focus on challenging the various cognitions and feelings that resulted in this strong connection’. 

Big Five

Cramer also advocates a network-based approach to personality. The Big Five is a well-known system describing normal personality on the basis of five traits: extraversion, agreeableness, conscientiousness, emotional stability and openness to experience. According to this theory, extraversion causes certain cognitions, emotions and behaviours that will be commonly recognised as extraverted.  According to Cramer, these traits – like mental disorders – should also not be regarded as entities located somewhere inside the individual's brain; each trait (such as extraversion) is the result of direct interactions between our cognitions, emotions and behaviour.

Publication details

Angélique O.J. Cramer: The Glue of Abnormal Mental Life. Networks of Interacting Thoughts, Feelings and Behaviors. Supervisors: Professor D. Borsboom and Professor H.L.J. van der Maas.

Time and location

The doctoral thesis defence ceremony will take place on Friday, 6 September at 14:00. Location: Agnietenkapel, Oudezijds Voorburgwal 231, Amsterdam.