At first, it seemed like a single drop, but it is quickly turning into a trickle. The first inkling was a study of >1,700 people with motor neurone disease (MND) which was published in the journal Neurology titled Depression in amyotrophic lateral sclerosis. The authors found that depression is a very frequent diagnosis shortly before people are diagnosed with MND.
Surely a coincidence, I thought. A rogue finding, or even an understandable response to illness. My excuses were however debunked by another paper published soon after in the Annals of Neurology. Titled Psychiatric disorders prior to amyotrophic lateral sclerosis, the study found that depression may precede the diagnosis of MND by more than 5 years. The authors also report a high frequency of other psychiatric conditions preceding the diagnosis of MND, such as anxiety and psychosis.
And just off the press is this report from Nature Communications titled Genetic correlation between amyotrophic lateral sclerosis and schizophrenia. What do we make of this? Is this just the tip of the iceberg? Surely more studies are needed before any firm conclusions. Perhaps this may lead to some early biomarker that enables neurologists to stop the process of progression to full blown MND. Perhaps.