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There is some suggestion that delusional types vary across culture. Some have suggested that delusions are more frequent in some ethnic groups, though this may simply be due to social influences. Some studies have not found differences in the incidence of delusions between white and black patient’s (Adebimpe 1981). A review of the delusions found in Malay and Chinese schizophrenics in Penang and Kota Bharu found that those in Penang tended to suffer more from sexual delusions and those from Kota Bharu from religious delusions. There was a non-significant greater presence of delusions of reference / jealousy in Penang and delusions of nihilism, guilt were more common in the Kota Bharu area (Azhar 1995). One study found that those who were married were more likely to develop sexual delusions but not religious delusions. Prevalence of grandiose and infidelity delusions may decrease as social class decreases. Those with more education may be more likely to have grandiose delusions. Immigration status probably has a part to play, e.g., immigrants to the UK were more paranoid. The youngest or only-children tended to be more paranoid, while the eldest tended to be more grandiose. Sexual delusions may occur more often in women and the married (Lucas 1959, Lucas 1962).

 

Amongst Bangladeshi schizophrenics, delusions of reference, persecution and control were most common in the employed, whilst grandiose delusions were more common in the unemployed. Urban dwellers had more delusions of reference / grandiose whilst rural dwellers had more persecutory delusions. The married had more reference and persecutory delusions and the unmarried more grandiose and control delusions. There was also a trend for more delusions with higher social class. Those with little education had more reference, somatic and persecution delusions, whereas the educated had more delusions of grandiosity and persecution. There is also evidence that delusions of reference and possession of thought increases with age (Ahammad 1991).

 

Amongst Indian schizophrenics, 23% had delusions of murder and assault. 22% had delusions regarding the body and sex. Delusions of murder, assault and philosophy were commonest in males and delusions of body organs, sex, magic, and religion was commoner in females. The over 30’s tended to have delusions of body organs, sex, magic and religion, while the under 30’s had more delusions of machines, wireless and technology. The unmarried were significantly more likely to have delusions of murder, assault, and machines. Rural dwellers had more delusions of murder, assault, magic, and religion whereas urban dwellers had more delusions of machines (Kala 1979).

 

Another study of delusions in Indian schizophrenics found that over 5 months, urban dwellers tended to have more delusions of reference, control, and influence, while rural dwellers more religious delusions. Married people had more sexual delusions and single people had more religious delusions. Delusions of paranoia, reference, sex, expansive, religious and hypochondriacal were more common in large families and delusions of paranoia, reference and expansive were commonest in large sibling groups. Paranoid delusions focused on groups, families, other and close associates. Expansive delusions focused on (in order) on status, power, other, skills and wealth. Sexual delusions focused on spousal infidelity, heterosexual sex being forced on them, other and masturbation (Sharma 1979). Phenomenological analysis of 112 schizophrenics found that systemisation and delusions of persecution were commonest in the over 30’s and in females. Single people tended to have more delusions of reference and in those with greater education there were more delusions of reference, misinterpretation and of thoughts being read (Kulhara 1986).

 

One interesting review looked at the delusions of schizophrenic patients from Tokyo Japan, Vienna Austria and Tuningen Germany. Their delusions were characterised and some of the positive findings were (Tateyama 1998)

• Japanese patients had

  • fewer hospital admissions but tended to stay in hospital longer

  • tended to feel slandered more often

• European patients were concerned about

  • being poisoned

  • hypochondriasis, guilt, nihilism, and poverty (more for Austria’s than Germans)

  • greater prevalence of religious delusions

• German patients had more delusions of jealousy

 

But another comparison of German and Japanese schizophrenic patients did not find a difference in incidence between delusional patients. Several results were given a p-value of 0.01 but were reported as significant and there did not appear to be correction for multiple testing. Also, exact p-values were not given for most of the comparisons. If you look at table 2 you can see that comparisons were made across 21 delusional types and across gender. I would calculate the adjusted p-value as 0.05/21=0.0024 and if you look at table 2, then I would argue there is no evidence for differences in the frequencies of delusions between the German and Japanese patients, nor for there being evidence of differences between the genders. They also compared differing content of paranoid delusions across countries and gender. I made the adjusted p-value to 0.05/15=0.0033 (see table 3) and I would argue there are no significant results (Tateyama 1993).

 

African patients from South Africa were studied when they were psychotic. One study found that of 85 females, belonging to the Tswana, Zulu, Xhosa, Sotho, Pedi, Swazi, or Shangaan tribes found delusions of being bewitched in 29 of them. 55 had delusions of paranoia related to feeling hated by others, that their lives were at risk. 49 had grandiose delusions, such as being prophetesses (Scott 1967). Another south African study looked at Xhosa and white patients with schizophrenia using the Relative Rating of Symptoms and Social Behaviour questionnaire and the Present State Examination. I made the adjust p-value 0.05/28=0.00178, as there were 28 t-tests done in Table 1. Hence, I feel the only significant differences were that black people were more likely to curse people, be stubborn, to get annoyed, to be cooperative, to talk to themselves and to be resentful. There were other results that were presented as significant, but they fell above the adjusted p-value, so I did not report them here. The PSE determined higher levels of persecution, sexual and fantastic delusions (Ensink 1998). See section on religion delusions for more.

 

One of the risk factors for delusions is social isolation, e.g., deafness. Some have felt that the ‘delusional’ process was essentially one where the individual conflicted with society (modern, as opposed to ancient societies) and this led to isolation as a final step. The difficulty in relationships between family, friends, work colleagues, etc. arises from difficulties that the person feels would lead to a loss to themselves and that this process of exclusion and isolation leads to the delusion. The final stage of the delusion process is where the person then finds themselves in a situation where they need others. This might be supported by the fact that those with delusional disorder have more social problems that those with schizophrenia (Hagen 1995). One study investigated the factors that influenced the contact rate between patients and their relatives. At baseline 47% had frequent contact with relatives, with 65% maintaining contact at two years. Females were more likely to have greater contact with relatives (OR 2.01 95%CI 1.42 – 2.83). Asians had the highest rate of contact, and compared to schizophrenics, schizoaffective patients had more contact with relatives (OR=1.75 95% CI 1.22 – 2.52) and affective psychoses (OR=2.09 95%CI 1.05 – 4.16), though this study did not have a control group with which to compare. This also did not look at delusions per se, but it supports the idea of differential contact between people and different mental illnesses. In the same study, when it came to continued contact with a relative, then the older the patient and having a live in relative predicted higher rates of contact (Harvey 2001).

 

Is it possible that social elements somehow lead to processes that can lead onto delusions? As opposed to simply being associated or confounded with them. There may be an element of this when we consider hypochondriacal delusions - the person develops symptoms which they think are due to physical illness, they then present to physicians who then proceed to do tests and find nothing. This can reinforce the notion that there is a physical disorder, but leave the patient frustrated and engaging in greater health seeking behaviour. This can lead to an angry patient and a frustrated doctor; hence psychiatric referrals are made which is often resented by the patient. As we will see later, anxiety, shame, depression, constant preoccupation, interruption to normal social processes, etc. are associated with delusions. This may produce a predelusional state, ripe for conversion into a full delusion (Sims 2003). This may be highlighted in a case of a manic individual, who developed delusions of pregnancy, while in a ward with a mother and baby unit (Miller 1992).

 

In today’s games there is a focus on violence (Forsyth 2001), which may be relevant - do computer related delusions follow the same type of content as found with the more ‘traditional’ delusions.  He described a young male who felt that he was a character in a computer game. He had become more withdrawn, felt people were trying to kill him, had auditory hallucination and felt the game was communicating with him by headphones. The game he was playing involved stealing cars, etc. and this eventually started in real life. A 27-year-old male felt controlled by the internet (Tan 1997). In India a 31-year-old male with paranoid schizophrenia had developed persistent persecutory delusions of control and hallucinations.  During the previous year he felt that his sister-in-law was controlling him via the internet and the computer. As neuroleptics had failed, he was treated with belief modification via reality testing, as he had no realistic concept of how the internet and computers worked and with explanation the belief had gone in about 3 weeks. The authors felt that ignorance and fear of new technology caused the delusion (Harpreet 2002). One study compared ten experiences of mind control from a web blog and compared them to reference networks from other non-mental health related networks. This study found that the network involved in the mind control blog, tended to be small, with a small ‘distance’ between individuals, resulting in more efficient transfer of information between members and the network tended to organise around key individuals (Bell 2006).

 

Those who favour an evolutionary view of delusions argue that the restricted range of delusional content may indicate that only a few brain systems are involved. But if societal changes can lead to a change in the expression of delusional content, then, at the very least, we must consider the interaction between society and evolutionary units, in the generation of delusions. This interaction must be highly non-linear and the individuals understanding may be the key cognitive element. Could there be a trajectory of delusional beliefs, constrained by societal, psychological, and biological rules? This may be supported by the fact that there doesn’t seem to be an infinite range to the content of delusional beliefs.