Mental illness is not uncommon in modern society, from mild to severe illness. Depression, (generalized) anxiety disorder, panic disorder and schizophrenia, to name a few. Do people with (long-term) mental illness are "destined" to be reborn in one of lower realms or they're seen just illnesses rather than unwholesome states of mind? What is the cause of mental illness from Dhamma point of view?
I think that unwholesome states of mind are conditioned and temporary.
It's difficult to generalise (i.e. I was told there are different results/experiences for different people) but if someone has a mental illness they may have seemingly unwholesome states of mind, and this condition might last for decades, for a lifetime -- but/or, a change in medication, a change in their social situation (friends), might condition a thorough "night and day" change in the states of mind even before the end of this life.
Sometimes it may seem that the range of (or the extremes of) experience is wider: i.e. a longer and more acute experience of a hell and/or a heaven (even in this life) than other more "normal" people will experience.
I'm not sure that Buddhism rightly talks about what's "destined" for people, i.e. perhaps it isn't correct to ask about it: because you can't predict the future and it may surprise you; because you should have some faith in the possibility of salvation, of becoming enlightened, of teachers, of refuge, of the three jewels; because there's some scope of agency and good (or bad) intentions, i.e. results are not predestined; and because the ability to see the effects of kamma on specific people is one of the Buddha's supernatural powers (and the fact that he did it sometimes doesn't mean that we should assume that we can).
Not much comes to mind but there is the Dhammapada verse from the Violence Chapter: Whoever uses violence .. Quickly goes to one of ten conditions: ... Bodily injury or insanity, .."
When it comes to hell realms, it is too abstract to say. The question is always what particular views, perceptions, tendencies and volitional formations are in play in the process of death because these will be giving rise to consecutive formations and desireablity of the result will be determined by the nature of the parent-states.
From Dhamma point of view you reap what you sow, so when asking what caused X, just by knowing things about X we can know some things about the things that caused it. So in example good is caused by good, bad is caused by bad, otherwise it would be paradoxical if something rightfully discerned as good was caused by something rightfully discerned as bad. If one doubts, pounders and does not gain conviction because of hypothetical situations in which bad actions seemingly have good results, that would be dependant on wrong understanding of the mechanics of Contact and therefore the Aggregates, basicly the whole analytical aspect is not grasped.
What is the cause of mental illness from Dhamma point of view? Well, it's attachment of course. Attachment to false, harmful concepts. Attachment to harmful sources of emotional energy. Attachment to old experiences. Even attachment to traumas.
Attachment makes us stuck, rigid, dysfunctional. "Klesha"s are mental and emotional obscurations that we generate through our attachment. Kleshas are like clouds that distort our perception of reality.
And why do we attach? Because we want to avoid pain. Physical pain, mental pain, emotional pain. We think that by holding on to one side, we can escape the pain associated with the other side. But that's an illusion, the more we avoid pain the more frightful and painful we make it. And that fear of pain becomes gasoline that feeds the engine of mental illness.
So from this standpoint the way to mental health is through letting go of attachments, letting go of fear of pain, letting go of extreme polarization, towards integration and acceptance of the opposites. Essentially letting go of false harmful concepts of the world and self, and the emotions associated with those concepts. This is why study of Emptiness is a key, because it leads to deconstruction of rigid concepts.
From the perspective of Enlightenment, we are all mentally ill in some degree. Mental illness is just a more blatant case of samsaric thinking, and Dharma is medicine for the mind.
It's not so conductive to try to figure out the line of Kamma, and such leads one to get crazy, as the Buddha told.
Good to know or accept, that phenomenas have causes, and unpleasant by previous and current unskillful deeds. It's clear that such "illness" will strongly increase in so called "secure" sociaties.
And as for the results of taking life... holding wrong view, he will feel them either right here & now, or in the next [lifetime], or following that. mn 136
Just think how many following such today, listen to people teaching such even here:
"Face to face with Gotama the contemplative have I heard this, face to face have I learned this: 'Bodily action is barren, verbal action is barren, only mental action is true. And there is an attainment in which, on being attained, nothing is felt.'"
"Don't say that, friend. Don't slander the Blessed One. For it's not good to slander the Blessed One; the Blessed One would not say that: 'Bodily action is barren, verbal action is barren, only mental action is true.' But there is, friend, an attainment in which, on being attained, nothing is felt."
Think about the big branch of cheaters all around and those acting on their account, especially in this realm, mental illness, the trade around it,and their psychiatrics... once living on them, once serving the others... bound are they together.
The best to beginn, if setting mind out to ways of liberation, is taking the full medicine as given by the Buddha: The Healing Power of the Precepts, and once established with firm convidence in the Tripple Gems, one virtue without spots, nothing is there which can really trouble the mind to low states.
There having been "crazy" people also at the Buddhas time who gained even Arahatship.
Wrong view, wrong ways of thinging, association with people of wrong view and acting on accord of this, is the cause of mental illness, the cause of realms of devastation, poorness, anxiety.
Approaching and associating with wise, with those of right view, bending ones ways of thinking according to their advices and act on this accord is the cause of good realms and even Unbinding, in the here and now.
Beings bound to those of wrong view, avoiding those with firm confidence and knowledge of the Buddhas way to really heal dis-ease, who aside they by themselves could help them to work on the liberation of their bounds?
So your turn. Beginning not to nurish and keep those with illness, those weaker, for ones personal gains, not harming, eating on them and turn to that of which is excalted, above, is the first step.
[Note: This is a gift of Dhamma, not meant for commercial use or other lower wordily gains by ways of exchange or trade]
Mental illness is not uncommon in modern society, from mild to severe illness. Depression, (generalized) anxiety disorder, panic disorder and schizophrenia, to name a few.
I suppose mental illness might need to be divided into two types:
Illness with biological origins, such as imbalances of chemicals or neural structures in the brain.
Illness with psychological origins, such as life experiences of emotional trauma.
Examples of psychological origins include people who have been subject to violence & abuse may develop anxiety disorder or people subject to loss of loved ones may experience depression, such as described in MN 87 (which does not refer to any cause, apart from in the here & now). The fact that people can develop anxiety due to violence explains why the Buddha taught about giving the gift of fearlessness (abhayadāna).
The noble disciple gives to an immeasurable number of beings freedom from fear, enmity and affliction. He himself in turn enjoys immeasurable freedom from fear, enmity and affliction.
What is the cause of mental illness from Dhamma point of view?
I do not recall any mention of biological mental illness in the Pali suttas. Although the term 'mental illness' is generally used in the world, imbalances of chemicals or neural structures in the brain have been said to really forms of physical illness, as follows:
In the time of the Buddha, "mental disease" referred to an illness of view or desire. These days, however, it refers to ordinary mental ailments that have their base in the body and are mixed up with physical disease.
Buddhism (SN 22.59) teaches every component of the body & mind can be subjected to injury, disease &/or illness (ābādhāya) due to decay, natural imperfection & impermanence. This is why mental illness can occur, either psychologically, biologically or a combination of both.
Do people with (long-term) mental illness are "destined" to be reborn in one of lower realms or they're seen just illnesses rather than unwholesome states of mind?
'Hell' is an unpleasant state of mind, as explained in the suttas. Therefore, people with mental illness are often already in a lower realm.
I have seen, bhikkhus, the hell named ‘Contact’s Sixfold Base.’ There whatever form one sees with the eye is undesirable, never desirable; unlovely, never lovely; disagreeable, never agreeable. Whatever sound one hears with the ear … Whatever odour one smells with the nose … Whatever taste one savours with the tongue … Whatever tactile object one feels with the body … Whatever mental phenomenon one cognizes with the mind is undesirable, never desirable; unlovely, never lovely; disagreeable, never agreeable.
As for the belief that "rebirth" occurs after the termination of life, similar to visions of schizophrenia, in my opinion, this also arises from "mental illness", as the term was used in the Buddha's time, i.e., illness of view or desire.
Schizophrenia is an illness characterized by a group of so-called “positive” symptoms that may include hallucinations (hearing voices, seeing visions), delusions (fixed false beliefs), and/or a thought disorder (speech that makes little sense).