It seems to me that most mental illnesses are diagnosed because a mental health professional asks them questions to identify symptoms to narrow down a diagnosis.
Are there other ways to test for mental illness like blood tests, brain scans, EEGs, etc?
Its my understanding that you can tell the difference between a sociopath and a neurotypical person on an MRI scan.
Supposedly people with narcissistic personality disorder have lower brain activity in brain areas involved in empathy.
With diseases where people refuse to get diagnosed (this happens with a lot of cluster B personality disorders) or diseases where you lack the insight to understand you are sick (schizophrenia, arguably depression, etc) are there other tests other than questionnaires?
Sometimes brain tumors have been blamed for a change in behavior. I am not sure if this is settled science though.
Perhaps most famously, the mass murderer Charles Whitman who shot many people from the University of Texas tower in 1966 was shown to have a brain tumor. Some suggest this was what changed him enough to commit the shooting. Not sure it can be known but it is something that could be tested for without a questionnaire.
Although Whitman’s autopsy revealed a pecan-sized tumor in the white matter above his amygdala, the tumor was not connected to any sensory nerves. Nonetheless, some experts believe this tumor may have contributed to the violent impulses which Whitman had been exhibiting for several years prior to the massacre.[3]: 54 [5] - SOURCE
I don’t know any conditions you can diagnose by blood test or EEG. AIUI MRI’s and CAT scans can show schizophrenua. But by that time, it’s usually obvious by the symptoms.
The differences in MRI don’t necessarily allow a diagnosis on it’s own - a neuroscientist named James Fallon was studying psychopaths and found that his own brain scans had low activity in areas linked to empathy and self-control, just like the psychopaths. Fallon and others refer to this as “pro-social” psychopathy - but the thing is, psychopathy and sociopathy are not actually diagnoses. They refer to a personality trait/behaviors The diagnosis would be anti-social personality disorder, which of course does not fit someone with low empathy, morality and self-control who nevertheless does keep their behavior within social bounds. A completely amoral person with no empathy can sometimes conform their behavior simply due to fear of consequences.
It is absolutely ‘settled science’, at least in the sense that various neurological conditions (brain tumors, ischemic strokes, traumatic brain injuries and chronic traumatic encephalopathy, prion diseases such as Crutzfeld-Jakob disease, severe epilepsy, alcohol and drug abuse) are broadly accepted to cause alterations in behavior and potentially remove inhibitions, and there is a long history of case studies supporting this. However, it is important to make the distinction between neurological disorders that have defined physiological cause and ‘mental illness’ which is a broad category of many different types of disorders, most of which are developmental, environmental, or genetic in origin. There are no mental health issues of this kind that can be determined through blood panels, EEG, MRI or CAT scans, or other purely physiological diagnostics, although these tools can be used to rule out neurophysiological or hormonal causes that can be treated by surgery, lifestyle alterations, or non-psychiatric pharmacological interventions.
The primary way of diagnosing mental health issues such as depression, anxiety, schizophrenia, PTSD, personality disorders, et cetera is through ‘questionnaires’ (which are really more of a sorting and intake tool), diagnostic interviews, and patient history and symptoms. There are genetic markers identified that serve as hallmarks for the potential for developing certain mental health issues such as schizophrenia or schizoaffective disorders but these are no guarantee when or if such a dysfunction will emerge, nor does the lack of these markers demonstrate that the individual in question cannot develop such a condition.
Seems like a condition is considered a neurological disorder rather than a mental health issue because we’ve been able to identify a physical cause that’s visible on brain scans, or else biomarkers visible on blood tests. Is there a chance more conditions will move from the second category to the first as we understand them better?
Actually no. Various conditions were already under the “neurology” umbrella before any gross physical cause was identifiable, or even diagnostic biomarker. And various “neurological” diseases have “psychiatric” manifestations (e.g. Parkinson’s disease)
Categorization between the two camps can be both fuzzy and arbitrary.
On the psychiatric/mental health side it is made more complicated because the same condition labeled by behaviors can be caused by a variety of genetically transmissible neurotransmitter causes, and the same genetically transmissible neurotransmitter differences can manifest in different labels.
Note that there are lot of medical conditions that cause mental problems as side effects. E.g., having an underactive thyroid can cause mental problems. A simple blood test can detect this and levothyroxine pills can fix it.
Like I said, a lot of medical conditions are like this.
Sadly, if you go to a therapist first, they are not likely to suspect an underlying medical condition.
It’s not so much moving from one category to the other because many are both.
For example, fronto temporal dementia. Readily diagnosed on MRI, and causes a lack of inhibition, often to a socially inappropriate degree.
Is that neurological or mental health issue?
Yes.
In terms of your question on whether increasingly more pathologies will be found to have a clear neurological cause, I would say absolutely. It’s why for example, I think justice systems based on the concept of punishment are going to struggle going forwards as we find neurological correlates for more and more behaviour. I could elaborate but this might already be too much of a hijack.