Mental Disease and Chemical Imbalances

I know little about psychiatry, but it’s popular knowledge that mental diseases are caused by certain types of chemical imbalances in the brain. This led me to wonder: What are the causes of these chemical imbalances? Is it simply genetics? Or is there more to it?

No one really know the “causes”.

Mental illness can, in rare instances, be caused by physical anamolies in the brain structure, by chemical imbalances, and often with no apparent cause. Genetics plays a role, but not the only role - environment can have an enormous impact, which is why stress can trigger mental illness.

So I don’t think there’s an exact answer to your question.

The ‘chemical imbalance’ line is a simplistic notion, used by pharmaceutical companies to advertise their wares. Mental illnesses have many complex reasons for existing - certainly some of those are genetic. And there’s strong circumstantial evidence for many disorders being inherited. So I agree with Broomstick - there’s no clear answer.

But doesn’t this work by the stress causing a chemical imbalance, which leads to the mental illness (ie depression)?

Just wanted to point out that chemical imbalances can also cause physical illness. For example, thyroid hormones. This leads me to sort of summarize that chemicals are involved in processes. When the wrong amount of chemicals are available, the processes do not work properly. In a sense it is society that has drawn a somewhat artificial line between mental and physical processes and disorders. Diabetics, for example, have obvious physical consequences from a chemical imbalance. But problems regulating blood sugar also affect mood.

And its not just the drug companies that push the idea that “chemical imbalances” cause disease. The dopaminergic theory behind schizophrenia is the prime theory used by researchers, drug companies and doctors in trying to treat patients. The same goes for depression. Doctors have to have some physical framework to base the diagnosis and treatment on, if possible, and the “chemical imbalances” to date are the best ideas to go on about why this physically happens. That does not mean these should be viewed in only those terms or that there are no other causes or considerations in the disease, but it does help give a basis to justify how to pick a medicine, what side effects to watch for, how to dose a medicine, etc.

“Chemical imbalance in the brain” is just a new way of saying “an excess of black bile.”

Uh, no, not really…there really are “chemical imbalances” that cause disease, despite the opinions of some here, but that probably is a poor, generic phrase for the problems. A lack of Dopamine, in a certain area in the brain, causes Parkinson’s disease. That is why replacing Dopamine, as in Awakenings, helps. Too much dopamine, especially on certain dopamine receptors, causes schizophrenia. Replacing Acetylcholine helps people with Alzheimers. Blocking NMDA receptors helps Alzheimer’s disease. Replacing serotinin and some other neurotransmitters helps depression. The list goes on. These are not rogue theories with no basis in fact. These are well researched areas and the chemical theory of brain disease is the driving force behind much of the research into causes of many misunderstand diseases.

           On the other hand, it is true that is not just the neurotransmitters being out of whack that causes the problem.  They also need receptors and it is the action of the chemicals on the receptors that causes problems, not just the increased or decreased presence of the chemical itself, so its no just always so simple as adding a little norepinephrine with a pinch of serotinin and a wee bit of glutamine.  Its not like you can come up with a recipe for curing someones mental or neurologic illness and put it in some kind of "neurotransmitter cake", but there is some basis to thinking of these diseases in this manner.  Otherwise we are left with going back and just think of schizophrenics as crazed religous zealots who need to be locked away and autistic children as poor kids that were never parented correctly.  This would be a huge step backwards and the chemical theories that have been developed have allowed us to step beyond these poorly thought out and limited views of neruopsychologic disease.

Certainly there is all kinds of legitimate research which correlates the presence / absence of certain chemicals with various mood / psychiatric / behavioral disorders. It is also true that certain medications demonstrably alleviate the distress of some patients.

OTOH, ‘mental diseases’ is at best a vague category, and correlation is not the same as causality. It could also be argued that ‘mental disease’ causes ‘chemical imbalance’, and that mental disease is caused by an ‘oedipus complex’…

As Harriet the Spry pointed out, ‘chemicals are involved in processes’ - but so are a number of other factors. It’s convenient to believe that altering body chemistry is the ideal path to mental / mood well-being, medication is fast and cheap compared to other therapies - but in many cases, this is tantamount to believed that wiping away tears alleviates sadness, and in the worst cases, patients with resolvable ‘life-problems’ are being encouraged to spend their days in a medicated stupor.

Sure, I didn’t mean to imply that changes in transmitter concentration, receptor expression and breakdown etc. etc. aren’t involved. It’s just that if engineers used terms of the same specificity as “chemical imbalance in the brain” to describe malfunctioning equipment we’d hear a capacitor with leaky dielectric described as
“an electronic imbalance in the amplifier.” Which term would be just about as useful in understanding the problem as “an excess of black bile.”

It’s way more complicated than the TV commercials portray. In addition to neutrotransmitter and receptor defects that HomerIU discussed, there can be structural abnormalities too. For example, in schizophrenia, certain parts of the brain are smaller. In some brain areas, it’s because there are less neurons, and in others it’s because the neurons are smaller and not as interconnected. And when you look at brain activity during certain cognitive tasks, these areas are less active. Which is probably due to a combination of neurotransmitter, receptor, and structural defects.

And it gets even more complicated, because different brain areas are affected differently in mental disease. Using schizophrenia as an example again, one hypothesis is that the symptoms of psychosis are caused by too much dopamine in one area, while deficits in cognitive functioning and social skills are caused by too little dopamine in another area. So just giving a drug that increases dopamine signalling won’t fix the whole disease. And other neurotransmitters affect dopamine transmission differently in different brain areas. That’s why the newer schizophrenia drugs act at lots of receptors in addition to the dopamine receptors.

As for what causes all of this to go wrong in the first place, nobody knows. Right now, most psychiatric diseases are diagnosed as clinical syndromes. Which means you categorize the patients as a certain disease based solely on their clinical symptoms, not on lab tests or things like that. So 2 schizophrenics may have similar symptoms, but different underlying causes for those symptoms. Which makes figuring out the causes that much harder. For schizophrenia, there are lots of competing theories about the cause (genetic, infectious, environmental, etc) all of which may be true, depending on the patient population you’re looking at.

Bottom line: the amount of stuff we don’t know about the brain far exceeds the amount we do know. Which is why neuroscience and psychiatry are so fascinating :slight_smile:

PS here is a damn funny spoof of the zoloft commercial

“And then there is this guy Larry who went totally apeshit and shot a bunch of people at the Dairy Queen.”

Hah. :stuck_out_tongue:

Hilarious spoof.

Being serious now: So can this sort of be considered a “chicken or the egg” question? e.g. “Which came first, the brain abnormality or the schitzophrenia?”

I don’t think there can be any question that at least one type of schizophrenia is related to brain chemicals, and that is the one that hits around 18 years of age. In the initial stage these people report they know something is going wrong.

But then on the other hand, it does happen that one identical twin will be infected and not the other. So…?

Say, thanks for that great spoof. Moo cha moo cha cha, moocha moo chacha :slight_smile:

What I always found interesting about schizophrenia is that everywhere in the world, the incidence is about the same : 1-2%. Makes it hard to argue for an environmental cause for the disease.

           ANd it is true that it is not as simple as replacing a few chemicals to cure these complex diseases.  It is obviously much more complex than that, otherwise, given the drugs that have been developed, curing people would be easy and I would be out of a job.

Well put. But in my area of the world (well in my maximum security prison), our incidence of schizophrenia among inmates is about 8 or 9%. And they sure aren’t cured with meds, even by being on 3 atypical anti-psychotic agents. But their behavior often does improve with these drugs. With none of the old zombie-like Thorazine shuffle, either.

I think that as time goes by, we’ll see better drugs developed, which diminish symptoms more with fewer side effects. But I’m not thinking that HomerIU will be out of work anytime soon!

You’re a psychiatrist? Cool. That’s what I wanna be when I grow up :smiley:

Anyway, I recently read a paper about how schizophrenics tend to be born in the winter, regardless of latitude. Now that’s pretty odd…

As long as it’s understood that stress does not always lead to an “imbalance”, I can agree with that.

Stress does cause a certain reaction in the body, and for most people that’s not an “imbalance”, it’s a normal reaction to stress. Remove the stress and they go back to their normal state - it’s when the stress is removed and normality does not return that you have a problem

In some case, a lack of stress can also trigger mental illness such as depression. Certain types of people, often considered “thrill-seekers”, when removed from the source of their adrenalin rush/stress, can sink into depression. In their case, a high state of arousal of the fight-flight response is normal, and it’s the stress-free state that, paradoxically, induces stress.

In other circumstances, a certain reaction that is normally considered negative is acutally normal. During grieving, for instance, people frequently display signs of depression: their sleep is disturbed, they lose interest in things, grooming might suffer, etc. But if your spouse just died those are normal reactions and not showing them might, again, be the indication of illness. It’s when grief never lets up that you know there’s a real problem.

Which is why this is all so complicated. There’s no one state/chemical mix that’s “normal” and all the rest “illness”

Much more. My lab (Alzheimers specialists) is starting a new collaboration with a Bipolarism (aka “manic depression”) laboratory. We’re going hunting for genetic polymorphisms that might correspond to different treatment responses. Psychiatry has figured out that one-drug-fits-all medications simply might not exist. It has already been well established that response to the first-generation anti-Alzheimer’s drugs depended upon genetic gender and a specific allele of the ApoE gene.

I know two people who have recieved serious head injuries, one from a motorcycle crash where hit hit the wall face first, and another in Northern Ireland from a bomb.

In both cases their personalities have changed quite dramatically but in differant ways, one has strange logic thinking and has an extreme polarised reaction to folk either they are his greatest freinds ever, or his worst enemies, and the other chap is in a permanently happy state and very optimistic - can’t find it in himself to hate or dislike anyone.

The optimistic one is the bomb victim which is not to draw conclusions, it’s just how he is.

I would not be surprised that the trauma of near death experience has had a considerable influence on both, add to that the damage caused by the incidents it really is difficult to establish which has influenced each person the most.

In jails we have a much larger rate of mental illness than the general population.
It’s also true that we have a much larger percentage of drug abusers too, I have seen some speculation that certain drugs can induce mental weaknesses in those who are susceptable, but it is hard to say which causes which, does drug use cause mental illness ? or does mental illness make drug use more likely ?

I have seen long term heavy cannabis users whose mental state is pretty much only a slight grasp on reality, but then I’ve also seen serious lifelong alcohol users with severe problems though this does tend to be accompanied by physical problems too, such as coordination problems etc.

The brain is a neurobiological organ: controled by electrical and chemical signals. When you take drugs, you are upsetting the chemistry of the brain, and this could lead to mental disorders. In the last job I had (before I retired), I read many cases wherein young individuals became psychotic after abusing drugs.

I always thought that bipolar and manic depression were different terms for the same disorder. However, someone who worked for a psychologist posted in another thread that there’s a difference. While a m-d will swing both ways (depression and euphoria), a bipolar will swing only one way. The difference, I guess, between a bipolar and depression, then, is that depression is always there, but in m-d, the person will be normal at times. Now, this is not what I’ve always thought, just what someone else posted. And I did know a young person who was bipolar who said that at one time the terms were interchangeable, but there’s a difference now. I did not question him at the time since I thought that he was wrong, and let it go.

The neuron is an electrically and chemically excitable nerve cell, and when activated by electricity (or magnetism), the nature of their signals changes: affecting everything from mood to cognition and memory. Electroconvulsive (ECT), or shock therapy, has been successful in depression which have been intractable to drugs. Somehow, the electricity alters the chemical signals. The latest is something called "echo-planar magnetic resonance spectroscopic imaging (EP-MRSI). It was discovered that the electromagnetic fields have a curative effect on depression. Another treatment, related to ECT, is rapid transcranial magnetic stimulation (RTMS), which creates a current by using a magnetic field.

There are also invasive treatments that have proved successful: vagus nerve stimulation and deep brain stimulation.