Sunday, August 11, 2013

Delusions and other Irrational Beliefs

The Working Dead
Cotard delusion (or Walking Corpse Syndrome):

A false belief that one does not exist or has died. Patients often believe that they turned into the walking dead. A relatively rare condition that was first described by Dr. Jules Cotard in 1882. Cases have been reported in patients with mood disorders, psychotic disorders, and medical conditions.

''O, beware, my lord, of jealousy;
It is the green-ey'd monster, which doth mock
The meat it feeds on.''  
Delusional jealousy (or Morbid jealousy):

A person with this delusion falsely believes that a spouse or lover is having an affair, with no proof to back up their claim. Morbid jealousy is a favourite topic among novelists and dramatists. ''Othello'' being a classic example.

Delusion of guilt or sin (or delusion of self-accusation):
This is an ungrounded feeling of remorse or guilt of delusional intensity.

Somatic delusion:
Heisenberg had bigger problems than Hank
A delusion whose content pertains to bodily functioning, bodily sensations, or physical appearance. Usually the false belief is that the body is somehow diseased, abnormal, or changed. A specific example of this is Delusions of Parasitosis: a delusion in which one feels infested with insects, bacteria, mites, spiders, lice, fleas, worms, or other organisms. Affected individuals may also report being repeatedly bitten.

Grandiose religious delusion:
The belief that the affected person is a god, or chosen to act as a god. A prominent topic in Freud's Schreber case study.

Capgras delusion (or Capgras syndrome):
A disorder in which a person holds a delusion that a friend, spouse, parent, or other close family member has been replaced by an identical-looking impostor. It has been described in psychiatric and neurological diseases. The onset of Capgras syndrome occurs at a significantly younger age and can be associated with psychiatric disease, cerebrovascular events, and illicit drug use (Josephs, 2007). See the film Changeling (2008) Well worth a watch!

Delusion of mind being read: The false belief that other people can know one's thoughts.

Delusions of persecution:

A delusion (common in paranoia) that others are out to get you and frustrate and embarrass you or inflict suffering on you; a complicated conspiracy is frequently imagined. Delusions of persecution are also common in schizophrenics, especially those suffering from paranoid schizophrenia.

Delusion of reference: The person falsely believes that insignificant remarks, events, or objects in one's environment have personal meaning or significance. Some schizophrenics may believe that current events are happening "for" them or because of something they did. Others may believe that the things strangers or celebrities do or say are meant as a message especially for them

Delusions of grandeur or megalomania:

Delusions of inflated worth, power, knowledge, identity. You may think you are a rock star, an actor or having a special relationship with a deity or famous person.  some schizophrenics may believe they are influential people from the past, such as Jesus Christ .

Any minute now...

Delusion of Reprieve:

Defined in psychology as a victim's false sense of hope in believing they will be pardoned in the last hour rather than meet their fatal end. It was poignantly discussed by Austrian psychiatrist and Holocaust survivor Viktor Frankl, in his inspiring book 'Man's Search for Meaning' (1946). 

Delusion of control: This is a false belief that another person, group of people, or external force controls one's general thoughts, feelings, impulses, or behaviour.

Famously described in Ian McEwan's novel Enduring Love, it is a delusion in which someone falsely believes another person is in love with them. The target may often be a celebrity or another high-status person, but people with Erotomania may also develop fixations on random strangers and acquaintances.  Erotomania has also been termed de Clerambault’s syndrome, after the French psychiatrist who identified the behaviour. A minority of people may attempt to injure or kill people who they perceive as standing in the way of their relationship with the object of their affection this has been sensationalized in films such as Fatal Attraction.

Reduplicative paramnesia (RP)

Reduplicative paramnesia is the delusional belief that a place or location has been duplicated, existing in two or more places simultaneously, or that it has been 'relocated' to another site. RP is thought to result from an organic rather than psychiatric cause.

It is one of the delusional misidentification syndromes and, although rare, is most commonly associated with acquired brain injury, particularly simultaneous damage to the right cerebral hemisphere and to both frontal lobes.
''We live and we die and anything else is just a delusion'' ~ Chuck Palahniuk, Choke

Monday, August 05, 2013

Was he blinking or winking?

An article that's a couple of years old now but still pretty interesting. Taken from BPS research digest (November 2009).

When a police line-up with six one-eyed men is better than a line-up with none.

To make it fair, they gathered as much Italian plumbers,
who spoke English and looked like Mexicans.
You're mugged by a man with a patch over one eye. You describe him and his distinctive appearance to the police. They locate a one-eyed suspect and present him to you in a video line-up with five innocent "foils". If this suspect is the only person in the line-up with one eye, prior research shows you're highly likely to pick him out even if, in all other respects, he actually bears little resemblance to your mugger. So the challenge is: How to make police line-ups fairer for suspects who have an unusual distinguishing feature?

Police in the USA and UK currently use two strategies - one is to conceal the suspect's distinguishing feature (and tell the witness they've done so); the other is to use make-up, theatrical props or Photoshop to adorn the other members of the line-up with the same distinctive feature. Theodora Zarkadi and her colleagues compared both approaches and found the fairer method is to replicate the unusual feature.

Zarkadi's team presented 110 undergrads with 32 photos of real-life inmates taken from the Florida Department of Corrections website. Photoshop was used to apply distinctive features including tattoos and piercings. Six of these distinctive "suspect" offenders were then embedded, one each, in six picture line-ups alongside five previously unseen "innocent" offenders. The participants' task was to pick out the suspect in each line-up.

The key finding is that the students made significantly more correct identifications when the innocents had been given an identical distinguishing feature compared with when the suspects' unusual feature had been hidden (approx 58 per cent accuracy vs. about 39 per cent).

This advantage was replicated in a second experiment in which the suspect was sometimes absent from the line-ups (akin to what can happen in real life). In this case, when the suspect was present, identification was again more accurate when the innocents also appeared with the same distinguishing feature (approx 50 per cent vs. 30 per cent). When the suspect was missing from the line-up (i.e. six innocents appeared), the students made false identifications on about 60 per cent of occasions, but this figure wasn't affected by whether the suspect, when present, had his unusual feature hidden, or if instead his feature was replicated in the innocents.

"Police officers should be aware of this ... empirical result when constructing line-ups for suspects with distinctive features and should replicate rather than conceal these features," the researchers said.
Zarkadi T, Wade KA, & Stewart N (2009). Creating Fair Lineups for Suspects With Distinctive Features. Psychological science : a journal of the American Psychological Society / APS PMID: 19883492