Schizophrenia and brain shinkage

Neuroleptic drugs, the same drugs used in the treatment of schizophrenia, in Macacque monkeys have been shown to cause brain tissue loss comparable to the kind of brain tissue loss we find in human beings labeled schizophrenic. As this abstract of a study in the journal Neuropsychopharmacology, The Influence of Chronic Exposure to Antipsychotic Medications on Brain Size before and after Tissue Fixation: A Comparison of Haloperidol and Olanzapine in Macaque Monkeys, puts it, “In conclusion, chronic exposure of non-human primates to antipsychotics was associated with reduced brain volume.” It stands to reason that if neuroleptic drugs reduce brain volume in non-human primates, they also reduce brain volume in human primates.

Apparently researchers into the matter of brain mass loss don’t share notes the way they should. If they did, they could save themselves a lot of wasted time and energy. I’m thinking about a much more recent study showing a brain mass loss in adolescents diagnosed with schizophrenia. MedScape Medical News published a story on this research with the heading, Brain Changes Found in Youth with Schizophrenia, Psychosis.

In a magnetic resonance imaging (MRI) study of more than 100 young people in Spain, those who were diagnosed with schizophrenia or other psychoses showed a greater loss of brain gray matter (GM) volume and a greater increase in cerebrospinal fluid (CSF) volumes in the frontal lobe after 2 years than did their healthy peers.

This 2 years wouldn’t be 2 years on a prescription of neuroleptic drugs, would it? If so, that could explain a lot. If these researchers had known about the study on Macacque monkeys, is it conceivable that maybe they would try to identify whether the brain tissue loss was due to neuroleptic drugs or “mental illness“? There is no indication in this article that they did so..

Progressive brain changes were also more significant in the participants with schizophrenia than in those with bipolar disorder (BD).

Yes, and while bipolar disorder may be treated with neuroleptic drugs, this is not always the case. Bipolar disorder is also treated with anti-convulsants and lithium. This potentially differing drug regimen is certainly enough to explain significantly different results.

We get the same sort of thing at in an article that asks, Is Cognitive Impairment a Feature of Schizophrenia? This short piece tells us about IQ tests conducted to determine whether or not cognitive impairment was a feature of schizophrenia, and it answers it’s own question in the affirmative. The question this piece doesn’t ask is whether the primary form of treatment for schizophrenia, neuroleptic drugs, had anything to do with this cognitive decline. One other thing that should be apparent is that significant brain shrinkage would mean cognitive decline, too.

What these researchers have neglected to do is to consider whether the brain shrinkage, and attendent cognitive decline, is caused by the “disease” or the treatment. The studies dealing with the monkeys showed brain mass loss associated with the use of neuroleptic drugs. The studies on humans don’t consider this factor, a factor of crucial importance, as to whether this brain tissue loss and cognitive decline is the result of the “disorder” or the drugs used to treat the “disorder”. Until they do so, this kind of research will remain misleading, and partial, as all the factors that might account for brain shrinkage and cognitive decline have not been factored in. Although we know that neuroleptic drugs are associated with brain shrinkage, and that this shrinkage must entail some cognitive decline, we can’t make the same claim for the schizophrenia label itself.