Psychosis

Psychosis is the state of being out of touch with reality.  Reality is an aggreement a society shares about the world we live in physically and socially.  For example, gravity is a concept of reality.  It is not uncommon for psychotic individuals to believe that the laws of gravity and other 'scientific realities' do not apply to them.  Hence a person may believe they can fly and jump off a building to their death.  This is an extreme form of psychosis.
At lesser levels of psychosis a person may believe that they are above the laws of society.  Such an individual may say the 'police can not arrest me' for any number of legal infringements such as having sex with children or assaulting women or threatening prime ministers.  These individuals truly believe they are 'immune' to such legislation and act with persistent astonishment throughout the police arrest and even during trials, often only coming to a real sense of reality when they are locked up for sometime in prison.  This individual may however may appear 'normal' in all other aspects of their life, whereas a more severe psychotic individual would have a lesser grasp on aspects of day to day living and be noted as odd often even by strangers.
When I was a member of the organization "Psychiatrists Against Political Abuse of Psychiatry" our principal concern at the time was totalitaran regimes like Russia then and China now which would accuse anyone who disagreed politically with being psychotic. Then they would lock  these indivduals, often world reknown scientists, up in asylums denying them all manner of human rights by claiming they were 'sick' and 'mentally ill'. While these kind of abuses occurred regularly internationally with psychiatrists voluntarily or sometimes involuntarily being part of the abuses I only witnessed such abuse extremely rarely in Canada.
When I was a member of the "Canadian Civil Rights Association" I was more often concerned about abuses against mentally ill patients.  Being psychotic can put an individual at extreme risk for abuse and exploitation by individuals and institutions  In these cases the rights of individuals who were ill were more likely being removed whereas it was rare for individuals to be called psychotic and treated as such by courts or state. The reason for the latter is the independence of psychiatrists generally in Canada and the legal system which requires psychiatrists often two, one for the state and one for the plaintiff when there is such a problem, to independently exam the individual.  Judges in Canada, generally being a rather reasonable and independent sort, usually make very good decisions in this regard based on the sometimes opposing presentations. Having declared probably a hundred or more individuals psychotic over the years I am pleased to say that none of my colleagues or the community at large disagreed with my diagnosis.  Individuals who felt they were superman, Jesus Christ, or had the right to having sex with their neighbours animals did take offense to my diagnosis but rarely did even family, friends or spouses. Indeed more often than not and especially in extreme cases the diagnosis of 'psychosis' is 'merciful' and helps protect an individual from themselves or others.  That said I do appreciated the patient advocacy groups such as the Canadian Mental Health Association which works as a watchdog over this process.
Psychosis can be brief or extended in time.  Brief Psychotic Episode is commonly in the range of hours or days.  Schizophreniform psychosis requires months for a diagnosis.  A typical manic psychosis untreated wiill last months.  Historically the diagnosis of schizophrenia required a year or four seasons of psychosis.  Typically these days in paranoid schizophrenia an individual will believe that their neighbours are spying on them, that car horns are being honked specifically and personally to bother them, that others can read their minds or that they can read the minds of others, that they have a special message from God or aliens to do something that in general that is not supported even by their mosque, temple or church or by the community they want to act out in.
One of the earliest and most unnerving features of psychosis interpersonally is when the other person accuses you of what they are in fact doing. Just last week I said in nearly a whisper to a manic psychotic patient, "please lower your voice, you're shouting' and their response countless decibels of volume above mine was ""I'm not shouting, you're shouting'.
This type of 'psychosis' is common when a person is emotionally challenged and their emotional range is peaked, either in anger or fear . so that they lose touch with where they leave off  and another begins.  At the extreme a schizophrenic patient whose room I entered was in utter terror and asked me to leave as I was 'stepping on his brain'.  Each of us carries a sense of self that is 'limitted' but a psychotic person might experience their sense of 'self' as 'expanded' and filling the room or encompassing others around them. This has been speculated as a regression to the infantile sense where a child doesn't separate their mother from themselves. In such a situation, and this is just one hypothesis for the well recogised phenomena of 'loss of boundaries,'  the individual who  "merges' so to speak can't separate their actions from those of others.  Hence the inability of the individual to recognise they were shouting, not I.
Locus of control refers to this the early aspects of psychosis in which the person feels that they are a 'victim' and deny that they are 'victimizing'.  They will say that they were 'made to do something' , they were 'forced to do something" as if they have no 'agency' in actions.  Later the same patient said "You're making me shout'" when we agreed they were shouting as I persisted in whispering. This locus of control and agency issue is readily apparent to trained observers and one can watch a person claim they have  no 'control' over any number of actions that community would say a person has control of. Hence the psychotic gunman would say he was not the agent of the killing of the children but rather that 'decadent west' made me kill them.
This is psychosis. It's important to note to that psychosis is common in drug abuse. It's extremely common in hallucinogens, routinely seen with cannibis consumption and extremely common with cocaine. The psychosis seen with these brain altering substances can persists months sometimes a year after a person has stopped using the brain altering substance.  It is more common to see the psychosis in such instances which is really close to the surface by watching the person when they are mildly frustrated, when they are unable to get something they feel 'entitled too'.
Just last month in my drug addiction practice I witnessed two relatively normal patients become acutely psychotic when I refused to write letters saying they were healthy and well and that I would approve of them and speak up for them having special priviledges that might put them in a position of risk to others.  In an instant they became threatening and verbally abusive and said that I was a 'devil', 'ruining their life' 'the cause of all the ill in the world' etc. It was certainly over the top, giveing me for more power, than I had and what I was suggesting was that we review their case in a week before I gave them a letter on their behalf. Given their psychotic reaction I was clearly 'right' in feeling they were not nearly as 'stable' as they insisted.  Indeed one person said they would 'hunt me down".  I think that individual wanted a bus pass so the reaction by all means seemed a tad extreme for what most people would consider 'normal' or based in 'reality'.  Not having a bus pass for a week is not reason to call a doctor the 'spawn of satan' yet that's perfectly reasonable in the reality of the psychotic individual where there is little measure outside the emotion and why this particular individual's psychosis would be further explained as 'emotioal reasoning'.  When this person is not 'frustrated' they are relatively reasonable but when they are in 'withdrawal' from cocaine everything in their world needs to have happened yesterday to be fast enough for them.
Much more can be said about psychosis. It's a 'state' that has many causes and can occur in many situations. It is seen in depression, anxiety disorders, substance abuse, thought disorders, personality disorders and post traumatic stress disorders.  There are treatments. The acute and more serious forms respond well to medications but psychological approaches can work in combination with social approaches over a much longer time frame.  Some chronic psychosis do not respond well to treatment but increasingly specialized units are being developed to deal with  these conditions where people are usually as a result of their psychosis a physical risk to themselves or others.