Brain scans alone cannot be used to diagnose a mental disorder, such as autism, anxiety, depression, schizophrenia, or bipolar disorder. In some cases, a brain scan might be used to rule out other medical illnesses, such as a tumor, that could cause symptoms similar to a mental disorder, such as depression.
As a result, fMRI infers brain activity by tracking where oxygenated blood is increasing in the brain (see the image in Figure 1D). With this information we can look at brain activity differences between people with different mental states and disorders.
Neuromarkers of mental health disorders
By 2013, scientists had identified neuromarkers for a variety of mental health conditions in MRI and other brain scans of people with schizophrenia, ADHD, bipolar disorder, depressive disorder and Tourette's.
Brain imaging can reveal unsuspected causes of your anxiety. Anxiety can be caused by many things, such as neurohormonal imbalances, post-traumatic stress syndrome, or head injuries. Brain scans can offer clues to potential root causes of your anxiety, which can help find the most effective treatment plan.
A PET scan can compare brain activity during periods of depression (left) with normal brain activity (right). An increase of blue and green colors, along with decreased white and yellow areas, shows decreased brain activity due to depression.
Can a brain scan show schizophrenia? It is not currently possible to determine that a person has schizophrenia simply by looking at a brain scan, but certain changes in the brain that can be observed on a brain scan have been associated with schizophrenia.
People who have psychotic episodes are often totally unaware their behaviour is in any way strange or that their delusions or hallucinations are not real. They may recognise delusional or bizarre behaviour in others, but lack the self-awareness to recognise it in themselves.
In patients with schizophrenia, MR imaging shows a smaller total brain volume and enlarged ventricles. Specific subcortical regions are affected, with reduced hippocampal and thalamic volumes, and an increase in the volume of the globus pallidus.
If imaging of the brain is needed in a patient with first-episode psychosis, an MRI should be preferred over a CT scan. This is because an MRI has much greater sensitivity for picking up brain pathology and because an MRI avoids exposure to ionizing radiation (Forbes and Stuckey, 2020).
Although studies on volumetric magnetic resonance imaging (MRI) analysis in schizophrenia have shown relatively consistent results over several decades (7), diagnosing schizophrenia based on these findings is still challenging and has little clinical utility.
Brain scans produce detailed images of the brain. They can be used to help doctors detect and diagnose conditions, such as tumours, causes of a stroke or vascular dementia.
With external brain scans and a powerful computational model of language, scientists could detect the gist of stories that people heard, thought or watched.
Psychiatrists are the only medical specialists who rarely look at the organ they treat. The odds are that if a patient is having serious problems with feelings (e.g., depression), thoughts (e.g., schizophrenia), or behavior (e.g., violence), the psychiatrist will never order a brain scan.
The main ones are hallucinations, delusions, and disordered forms of thinking. Hallucinations means seeing, hearing, or feeling things that don't exist.
Brain tumors and brain injury.
Some brain tumors may cause psychotic symptoms that seem like schizophrenia. Likewise, people who've had a traumatic brain injury may have symptoms such as psychosis.
As found during functional MRI scanning, the anxious brain also has a decreased connectivity network in key brain pathways — specifically, in a structure called the amygdala. An earlier study in patients with a generalized anxiety disorder had similar results.
Though brain scans cannot yet reliably diagnose ADHD, some scientists are using them to identify environmental and prenatal factors that affect symptoms, and to better understand how stimulant medications trigger symptom control vs. side effects.
Brain scans may be helpful in showing the differences in the structure and function of brain regions in individuals with OCD. Such studies can provide new targets for the treatment of OCD.
Functional MRI studies on patients with major depression demonstrated abnormal excitations and inhibitions in the prefrontal cortex also known as the connectome - the network of neural connections within the brain. This part of the brain governs cognitive ability and emotions.