Is schizophrenia a cognitive Illness rather than a psychotic disorder? JAMA PSY. Oct.2013

04.11.2013

Schizophrenia is classified as a psychotic disorder. Is it more of a cognitive disorder than one defined presently by presence of psychotic symptoms? Has emphasis on psychotic symptoms lead us to a blind alley? Was wrong focus the reason for lack of meaningful progress in treatment ever since the disease was described? Kahn and Keefe  make a strong argument to reconsider schizophrenia as a primary cognitive disorder in this article.

Cognition in this article reflect any measure of cognitive performance such as memory, attention, acquisition of knowledge, processing speed, reasoning, and executive function.

They make five arguments in  support of their idea

1.Poor cognition is  a risk factor for schizophrenia. for example large Swedish study showed that children with the lowest grades had a 4-fold risk for developing schizophrenia. 2. Cognitive decline presents before the onset of psychosis. Individuals who later develop schizophrenia are more likely to show progressive lag or relative cognitive decline years prior to onset of illness 3. Cognitive decline continues after the onset of psychosis.cognitive performance is 1 to 2 standard deviations (SDs) lower than age-matched control subjects. 4. Poor premorbid cognitive decline show specificity ie cognitive dysfunction prior to psychosis onset may distinguish it from other psychiatric disorders. The evidence described suggest that mean cognitive underperformance during adolescence and at first presentation of psychosis differentiates schizophrenia from bipolar disorder. 5. Cognitive decline predicts the functional outcome.

Counter view:  1. MOST individuals with poor cognition will NOT develop schizophrenia. 2.Cognitive underperformace may not distinguish schizophrenia from bipolar disorder . In fact they may share many features including impaired cognition. 3. Distinction between schizophrenia as condition of cognitive decline and others ( bipolar/ other psychotic disorders)  with normal cognition is  less realistic. 4. Authors do not explore / offer explanation for recovery observed in schizophrenia.

In the accompanying editorial  Stephen Heckers  agree that cognitive underperformance deserves more attention  in diagnostic assessments and treatment targets.The call to discard it as a psychotic disorder is described as premature.

Comment: It is possible that all symptoms of schizophrenia could  be explained as failures of cognitive function, if we consider all thoughts and behaviour as expressions or experiences built  fundamentally from simpler cognitive processes, which we may not have clearly understood or measured yet.

Summary of the article:

Schizophrenia is a cognitive illnesstime for a change in focus. Kahn RS, Keefe RS.JAMA Psychiatry. 2013 Oct 1;70(10):1107-12

2 thoughts on “Is schizophrenia a cognitive Illness rather than a psychotic disorder? JAMA PSY. Oct.2013

  1. WHAT A REFRESHING AND EXCELLENT OUTLOOK TO PROBE DEEPER INTO. I COULDN’T AGREE WITH YOU MORE ABOUT DETERMING AND DIAGNOSING AN ILLNESS OF COGNITION PRIOR TO LABELLING WITH PSYCHIATRIC ILLNESS. WHEN I STOP TO THINK ABOUT IT, IT’S SO OBVIOUSLY SIMPLE, IT’S JUST COMMON-SENSE. I HAVE FIRST HAND EXPERIENCE IN LIVING WITH SAME. THIS BORDERS ON A TOUCH OF INSIGHT AND GENIUS. CONGRATULATIONS AND GOOD LUCK IN YOUR ENDEAVOURS. REGINA CROTHERS

  2. Or should we redefine the term ‘cognition’?. Originally meant to describe the deficit in organic brain syndromes, several processes used for ‘knowing or making sense of the world’ are subsumed under the term ‘cognition’ May be we should try to separate the individual components affected in Schizophrenia and in organic brain syndromes.

    Sudhakar Bhat.

    On 4 November 2013 16:58, Psychiatrist:Update

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