The brain became a celebrity this week when Ariana Grande shared the results of a scan of her brain seemingly showing signs of severe PTSD:

Is there any science behind this? Not really. The source of the scan isn't clear but I'm 99% sure that the image was taken at one of Dr Daniel Amen's controversial clinics. Amen uses similar graphics in his brain scans. If it is an Amen scan, then the 'blobs' seen on Grande's brain represent areas of increased or decreased cerebral blood flow (CBF) as assessed using a method called SPECT. SPECT is a fairly old neuroimaging methodology that forms the heart of Amen's network of clinics. Bear in mind that the blobs on an image like this are statistical illustrations. A scan like this is not a photograph or x-ray of structural changes, and without knowing the context in which the scan was taken and the methods used to analyze it, it doesn't mean much. Most psychiatrists and neuroscientists would not use SPECT or any other type of brain scan to diagnose PTSD. Dr Amen claims to be able to do so, and in 2015 published a paper reporting on this, but I wouldn't put much faith in it. In the 2015 paper, Amen et al. report that in one sample of 104 PTSD patients and 116 healthy controls, they could detect PTSD using SPECT with literally perfect 100% accuracy. This is simply not believable. If that's a real result, I am Pete Davidson. Amen et al. went on to report that in a larger sample of 1077 PTSD vs. 11147 people without PTSD (but maybe other disorders), their ability to detect PTSD was much lower, although better than chance. However, the methods by which diagnoses were inferred from the brain images are so poorly described in Amen et al. (2015) that it's anyone's guess if this is valid. I'm surprised the paper passed peer review. Overall, I've no reason to doubt that Ariana does have PTSD, but the brain scan tells us nothing about it, and this whole story is an example of the allure of brain images which promise to make mental phenomena "real".