Metabolomics in Psychiatric Disorders: What We Learn from Animal Models, 2020, Humer et al

Andy

Retired committee member
Biomarkers are a recent research target within biological factors of psychiatric disorders. There is growing evidence for deriving biomarkers within psychiatric disorders in serum or urine samples in humans, however, few studies have investigated this differentiation in brain or cerebral fluid samples in psychiatric disorders. As brain samples from humans are only available at autopsy, animal models are commonly applied to determine the pathogenesis of psychiatric diseases and to test treatment strategies. The aim of this review is to summarize studies on biomarkers in animal models for psychiatric disorders.

For depression, anxiety and addiction disorders studies, biomarkers in animal brains are available. Furthermore, several studies have investigated psychiatric medication, e.g., antipsychotics, antidepressants, or mood stabilizers, in animals. The most notable changes in biomarkers in depressed animal models were related to the glutamate-γ-aminobutyric acid-glutamine-cycle. In anxiety models, alterations in amino acid and energy metabolism (i.e., mitochondrial regulation) were observed. Addicted animals showed several biomarkers according to the induced drugs. In summary, animal models provide some direct insights into the cellular metabolites that are produced during psychiatric processes. In addition, the influence on biomarkers due to short- or long-term medication is a noticeable finding.

Further studies should combine representative animal models and human studies on cerebral fluid to improve insight into mental disorders and advance the development of novel treatment strategies.
Open access, https://www.mdpi.com/2218-1989/10/2/72
 
How Depressed Is That Mouse?
In “Lifting the Black Cloud,” Robin Henig surveys the search for new, improved antidepressants. Much research in the area involves laboratory mice and rats. Here, Henig explains how scientists determine whether a rodent is depressed.

It’s hard to develop an animal model for depression. As Michael Kaplitt of Cornell Medical College puts it, “A mouse can’t tell you how it’s feeling.” Scientists have had to come up with proxy behaviors, actions that they interpret as “depressionlike,” to measure whether particular drugs or therapies are having an effect. To identify depression in laboratory animals, investigators rely on the following:
https://www.scientificamerican.com/article/depression-how-depressed-is-mouse/

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Given the extremely poor track record of properly diagnosing psychiatric disease in humans, who can actually answer complex questions and provide additional information, I would not bet a nickel on a mouse model of any psychiatric disease, especially depression and anxiety, whose diagnoses have basically zero reliability in humans as it is and it is entirely based on asking questions, which as far as I am aware mice struggle to do.

Especially as by far the biggest problem is in being easily fooled over superficial features, which are the only features that can be used in an animal model. Psychiatry can't even properly use some simple concepts like fatigue in actual humans and redefines their meaning to fit contextual needs.

Lots of work ahead before this can yield anything of value.
 
Feynman said that in science, the easiest person to fool is yourself. Psych seems to be saying "Fool me? Where's the money? Step it up to Fool U!"
 
There are animal models for psychiatric diseases. One of the most curious is attention deficit disorder. In Australia they had a breeding programme for police dogs, drug sniffers and the like. They needed working animals who were not easily distracted but they also ended up with dogs who could not concentrate on anything.

Also with pets it is easy to tell that some animals are timid and some are bold and zoo keepers have done a lot of work in the past decades preventing apathy in their animals.

I think it is not often done well but there is a place for good research using animal models as it can highlight basic biology as well as proving that it is not all down to bad cognitions in humans. Animals do not hide their symptoms and feeling the way humans do.
 
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