Meditation for Psychosis I have psychosis.
I have no ability to understand reality from birth.
Can meditation give me the ability?
Or will I never be able to end my mental suffering?
Do you know how can I end my pain and fear, and get peace and happiness?
Welcome to the site.

I can't give a complete answer; but maybe an outline of an answer in note form. Please feel welcome to ask follow-up questions (using comments or separate questions) when you want any further details.



I've looked for, but I haven't been able find, information related to your question -- i.e. I haven't found Buddhist meditation teachers saying that they have experience of teaching people with psychosis (I have found teachers who said they don't have that experience).

I don't know where you live or who you're in contact with: but I hope it might be worth your while to ask some 'professionals', for example asking ...


Your psychiatrists
Local meditation teachers


... whether they know any suitable meditation classes/programs, and/or teachers with that experience.

For example I found this video, Enlightenment, DP/DR &amp; Falling Into the Pit of the Void.



Buddhism is also known as the threefold training:


Virtue (morality)
Mind (concentration or meditation)
Insight (wisdom)




Virtue (morality)

The first of these is virtue/morality.  In Buddhism, morality might be summarized as "harmlessness" or (in slightly more detail), the "five precepts" which are:


Avoid killing
Avoid stealing (or "taking what is not given")
Avoid sexual misconduct
Avoid lying (or "false speech")
Avoid alcohol


There are many benefits to keeping the five precepts.

Note that "keeping the precepts" was the sum total of Dean's answer, and it's not a bad answer.

There's a sutta, Kimattha Sutta: What is the Purpose?, which begins with,


  ... he said to the Blessed One: "What is the purpose of skillful virtues?
  What is their reward?"
  
  "Skillful virtues have freedom from remorse as their purpose, Ananda,
  and freedom from remorse as their reward."
  
  "And what is the purpose of freedom from remorse? What is its reward?"
  
  "Freedom from remorse has joy as its purpose, joy as its reward."


I recommend you read the whole thing.

My point is that that skillful virtues, i.e. "virtues" or being harmless, which is called sila, result in a "lack of remorse".

My experience is that this is very, very important. Even if psychosis means that you can do nothing else, at least knowing the difference between right and wrong, and doing no wrong, will mean that you have no reason to feel remorse, no reason to 'feel bad' about yourself. It makes a world of difference to you and to those around you.

So even if nothing else, do no harm: that's the beginning (of 'peace and happiness').



Mind (concentration or meditation)

The second part of the training includes concentration.

There are many, many types of concentration meditation. I'll mention two:


Breathing meditation ("mindfulness of breathing")
Loving-kindness meditation (called "metta bhavana" in Pali, this chant is an example)


The ability to "concentrate" might ultimately be developed into the jhanas,


  Jhana is a meditative state of profound stillness and concentration in which the mind becomes fully immersed and absorbed in the chosen object of attention. It is the cornerstone in the development of Right Concentration.


Maybe this too is what you're looking for, when you're asking about how to attain "peace and happiness".



Some people warn though that it's possible to get a little lost in "concentration" meditation, and that you ought to practice "insight" meditation. I think that's what's meant in the last paragraph of Suminda's answer ("excessive concentration is not advisable").

Insight (wisdom)

Suminda advocates a form of meditation called Vipassana. I think that the purpose of this form of meditation is to observe everything (including body, mind, feelings, and ideas) and to experience the fact that they're impermanent, that they come and go, arise and disappear.

I think that's connected with the so-called "four noble truths" of Buddhism, including the 3rd truth i.e. "cessation".

You'll find more about "Vipassana" if you search for it (I won't try to explain it in this answer), and/or maybe you can find someone who teaches it in person.



Equanimity

I think that one of the states-of-mind which people try to develop using Vipassana (or to put it more impersonally, a state of mind which is developed as a result of Vipassana) is equanimity.

I think that too is related to the four noble truths.

You say, "how can I end my pain and fear" but part of the point of Buddhism is that wanting something makes it worse; for example:


"I'm feeling pain and fear, and that's so bad, I wish it would stop, but it's not stopping, I don't know how to make it stop"


... compared with ...


"Oh that's an experience of a feeling, which in the past I used to label as 'pain and fear' ... there's the feeling ... oh, there's another feeling now, the previous feeling has gone (was impermanent, has ceased)"


I suppose that (equanimity, and knowledge of impermanence) is a result of insight or wisdom.



Love

Actually equanimity is one of the four Brahmaviharas -- of which, the other three are various kinds of love (called metta, mudita, and karuna in Pali).

Here's an essay about the Brahmaviharas.

Someone like the Dalai Lama recommends these kinds of attitudes towards other people. Not only can it be a skillful way to behave with other people (it may be better to feel compassion than anger, for example), but caring about people means caring less about yourself, and/or caring about yourself in the same way that you care about other people. The Dalai Lama has said that he would feel "imprisoned" within himself if he only cared about himself, and that he prefers to see himself as "like other people".

Maybe that's why meditations like the metta gatha include equally "may I be free from suffering" and "may each and every other person be free from suffering".



Psychosis

The OP doesn't mention what the specific symptoms of psychosis are.

Here are some of them as described in Wikipedia:


Hallucinations
Delusions
Thought disorders


Here is some of what I know about these symptoms and some guesses about how Buddhist meditation might be able to help with them.


Hallucinations might include the classic "hearing voices" which means "hearing" or perceiving a thought as if it were a voice. A simple example might be, you're waiting at a bus stop, and you hear a voice saying "that bus isn't coming" but there's no-one else there. So that "voice" was just a thought.

From a mundane point of view, this might be a symptom to discuss with your psychiatrist. I take it you know that there are anti-psychotic drugs, that they're more-or-less effective, that they have unwanted side-effects, that there are many types of them, and that it's guess-work or trial-and-error to find a prescription that suits a specific patient. For some people, the right drugs can relieve symptoms such as hallucinations: so if you experience hallucinations that might be something to tell your psychiatrist, in case they're able to (more or less harmlessly) adjust your prescription.

From a Buddhist point of view, I'd like to suggest that as long as you're able to do no harm, then it doesn't matter. For example, hearing a voice is harmless, whereas hurting someone would be harmful. If you hear a voice but don't hurt people then you're doing very well (and I respect and admire you).

In other words, that may be connected with the "virtue (morality)" part of the path.
Delusions might be, for example, paranoid (believing that others want to harm you), or grandiose (believing you have special power or skills).

To counteract paranoid beliefs, I guess that metta bhavana ("cultivation of loving-kindness") might be helpful. If you don't want to hurt others then they shouldn't want to hurt you. If you see others as suffering (or being freed from suffering) you're less likely to see yourself as suffering (or being persecuted).

To counteract grandiose beliefs, well, I guess I recommend "virtue" again. For example it's alright to see yourself as virtuous if you are virtuous, and alright to see yourself as helping people if at least you are not harming them.
Thought disorders are difficult to talk about, because it means for example that your ability to understand words (speech and writing) is disorganized.

It may or may not help you to know that Buddhism identifies like 12 links in the chain of existence, and that "words" are only one of these links (i.e. sankharas or "fabrications"), and they're arguably the least important and/or the most easily misunderstood link. People tend to be deceived by their own "fabrications". If you can't follow what they say then maybe you will be seen as disabled (and I think maybe you would be 'disabled', because it's typically better if you can say things that people understand) but it's not the end of the world: there are other aspects to reality (e.g. senses, consciousness, feeling, etc.).

I think it's possible to communicate even when there are thought disorders, for example, by being kind to people.

There's a story I remember of the Dalai Lama's meeting someone in the crowd who was disturbed, and holding his hand until he calmed down and found some peace.

Again, anti-psychotic drugs might be able to alleviate the symptom of "thought disorders", which then makes other forms of communication (and/or healing, helping, employment) possible.




Finally it would be amiss to talk about Buddhism without mentioning friendship and community.

One of the Three Jewels of Buddhism is the Sangha,


  Sangha is a word in Pali and Sanskrit meaning "association", "assembly," "company" or "community" and most commonly refers in Buddhism to the monastic community of ordained Buddhist monks or nuns. This community is traditionally referred to as the bhikkhu-sangha or bhikkhuni-sangha. As a separate category, those who have attained any of the four stages of enlightenment, whether or not they are members of the bhikkhu-sangha or bhikkhuni-sangha, are referred to as the ariya-sangha or "noble Sangha".


Related to that is the "noble friend", for example the Upaddha Sutta. I'll quote it in full:


  Upaddha Sutta: Half (of the Holy Life)
  
  I have heard that on one occasion the Blessed One was living among the
  Sakyans. Now there is a Sakyan town named Sakkara. There Ven. Ananda
  went to the Blessed One and, on arrival, having bowed down to the
  Blessed One, sat to one side. As he was sitting there, Ven. Ananda
  said to the Blessed One, "This is half of the holy life, lord:
  admirable friendship, admirable companionship, admirable
  camaraderie."[1]
  
  "Don't say that, Ananda. Don't say that. Admirable friendship,
  admirable companionship, admirable camaraderie is actually the whole
  of the holy life. When a monk has admirable people as friends,
  companions, &amp; comrades, he can be expected to develop &amp; pursue the
  noble eightfold path.
  
  "And how does a monk who has admirable people as friends, companions,
  &amp; comrades, develop &amp; pursue the noble eightfold path? There is the
  case where a monk develops right view dependent on seclusion,
  dependent on dispassion, dependent on cessation, resulting in
  relinquishment. He develops right resolve... right speech... right
  action... right livelihood... right effort... right mindfulness...
  right concentration dependent on seclusion, dependent on dispassion,
  dependent on cessation, resulting in relinquishment. This is how a
  monk who has admirable people as friends, companions, &amp; colleagues,
  develops &amp; pursues the noble eightfold path.
  
  "And through this line of reasoning one may know how admirable
  friendship, admirable companionship, admirable camaraderie is actually
  the whole of the holy life: It is in dependence on me as an admirable
  friend that beings subject to birth have gained release from birth,
  that beings subject to aging have gained release from aging, that
  beings subject to death have gained release from death, that beings
  subject to sorrow, lamentation, pain, distress, &amp; despair have gained
  release from sorrow, lamentation, pain, distress, &amp; despair. It is
  through this line of reasoning that one may know how admirable
  friendship, admirable companionship, admirable camaraderie is actually
  the whole of the holy life."
  
  Notes
  
  
  As AN 8.54 points out, this means not only associating with good people, but also learning from them and emulating their good
  qualities.
  


I hope that suggests another way to "end my pain and fear, and get peace and happiness": i.e. have a friend, have several friends, be a friend, seek and be with friendly (harmless) people.

See also Kalyāṇa-mittatā or Friend who is the same in happiness and sorrow.