van den Hout2014 - Psychiatric Symptoms as Pathogens

  • Type:#article
  • Year read:#read2021
  • Subject: OCD Network theory
  • Bibtex: @van2014psychiatric
  • Bibliography: van den Hout, M. (2014). Psychiatric symptoms as pathogens. Clinical Neuropsychiatry, 11(6), 153–159.

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Key takeaways

  • When symptoms constitute disorders, as in psychiatry, it doesn’t make sense to say that disorders cause symptoms.
  • One way to circumvent it is to look for biological or physiological parameters that are specific, but this has not resulted in any reliable indicators of disorder 1 vs disorder 2
  • Network theory, CBT and experimental psychopathology are “intellectual allies” that reinforce each other

A different approach is to regard psychiatric symptoms not as ‘output’ from underlying, yet to be identified (pathophysiological dysregulation), but to consider symptoms as “input” that causally contributes to other symptoms.

Psychiatric disorders, unlike other branches of medicine, are defined by the symptoms. So we cannot say that someone has schizophrenia because of a brain tumor even though no symptoms are seen, we can’t say someone has a phobia in the absence of phobic symptoms.

Why is Peter so sad? Because he suffers from depression. But how do we know he is depressed? Because of his sadness.

How do we get around this tautology?

Treat the disorder as something to be explained, not as explanation

Identify pathophysiological processes that underlie the conditions. Even if we can’t understand the mechanisms then at least we should be able to identify markers: genetic profiles, physiological tests, results from brain imaging etc.

He thinks that the optimism around biological approaches did not pay off in terms of clear markers or mechanisms for specific disorders.

Forget about descriptive disorders, explain symptoms

We have high rates of comorbidity, so if each category in the DSM had distinct pathogenetic profile, why do they co-occur so often?

Looking for explanations for a specific disorder is misguided, look instead at discrete symptoms. However, symptoms often cluster in meaningful ways, for example hand washing and checking rituals, so we should not let go of symptom combinations.

Symptoms as causes of other symptoms: network theory

Instead of saying that the symptoms of depression are caused by depression, the symptoms can be viewed as active causal components.

Enduring environmental stressor -> depressed mood -> self-reproach -> insomnia -> fatigue -> concentration problems.

An explanatory model should explain (1) symptoms of mental disorders come in reliable combinations, (2) co-morbidity is widespread, (3) there are no biological markers for specific disorders. How network theory explains these:

(1) Sleeplessness more likely to induce fatigue than agoraphobia. Unpredictable panic attacks more likely to promote agoraphobic avoidance than sleeplessness.

(2) Comorbidity can be explained by overlapping symptoms, Symptoms occuring in multiple disorders can bridge activation between the networks

(3) According to network theory there are no such markers to begin with.

Applications in OCD research

How Network theory, CBT, and experimental psychopathology inform each other

Eysenck said “if you take away the symptoms you have cured neurosis”. Clark’s model of panic disorder is a breakthrough since he said that symptoms were mutually reinforcing.

In OCD, does responsibility for harm drive compulsions? This was shown in an experimental study with high/low responsibility instructions. (Lopatka and Rachman, 1995). BUT, no actual behavior studied here, only, self-reported urges to act.

Arntz et al 2007 (pill sorting task) found that urges to check increased in high-responsibility condition but more so for OCD patients compared to other anxiety or healthy controls.

van den Hout’s own gas stove experiment. Lower memory confidence after repeated checking, seen in OCD patients and healthy controls alike, but OCD patients have lower confidence to begin with. He argues that there is automation after multiple checks that drives this decreased processing of perceptual details.

Obsessions and compulsions are not merely inert symptoms of an underlying disorder, but they serve to mutually reinforce one another: Obsessions <-> Compulsions.

Symptom-symptom relations

Guilt and responsibility -> Compulsions

Perseveration of compulsions -> Uncertainty