Strange Beliefs and Mental Illness

If you believe that 2+2=5 is true, are you suffering from a psychotic delusion or simply misguided?

How does a person's beliefs relate to his or her overt behaviour? This is a topic that has long been studied in social psychology. It is evident from research, as well as one's everyday experience, that there is some disconnection between the two; that is, a person's expressed beliefs and attitudes do not necessarily predict how he or she will behave in situations in which they are relevant.

I previously talked hypothetically about people who believe that two plus two make five and I suggested that a healthy society is one that would tolerate this belief but not, in many situations, the behaviour that would be predicted by it. Now I ask the question 'Are people who believe "two plus two make five" mad?' (or at least, 'Do they have a mental disorder?'). I am assuming that for these people the words 'two', 'plus', 'make' and 'five' mean the same as for the rest of us. (In passing it may be noted that there is a rare psychiatric disorder called Ganser's syndrome, or hysterical pseudo-dementia - of which I have only ever seen one 'classical case' - whereby, amongst other things, the patient gives approximate answers to very simple questions and hence may give the answer 'five' in reply to 'two plus two make what?'. The same may be observed with some highly hypnotically susceptible people when it is suggested to them that, say, the number four no longer exists.)

To decide on the answer to the above question let us consider in greater depth the nature of clinical delusions and take a more useful example, namely the belief that our leading politicians are aliens from a distant planet. Let's suppose that someone, whom we shall call John, insists that this is true. Is John suffering from a psychotic delusion or is he simply misguided? And indeed, who are we to decide that he couldn't possibly on to something here?

When we ask such questions we must bear in mind that people who are clinically deluded often endure great mental suffering and they are also the cause of much distress for their family and friends. Nevertheless it is relevant to ask these questions and one clue is to ascertain how John arrived at his beliefs. For example he may tell us that he has been informed about the matters in question by coded messages on television and radio, or similar information he has read in the newspapers. He may believe that these coded messages are secret communications, intended only for extra-terrestrial spies planted in our midst, but that he has some special ability to decode them.

This kind of personalisation of the belief system is very telling and may also include persecutory beliefs. For example John may believe that secret agents are aware that he has discovered what is happening and are spying on his house and tapping his telephone, and they have persuaded his neighbours to report to them what he is doing. (Most often the person will only be claiming that he or she is the target of this kind of campaign and not others that he knows of.)

Even if John's beliefs were to become as extreme as this we may still ask what harm anyone suffers on account of them and on what grounds one should label him as 'sick' and 'in need of medical attention'. And this is where we once again need to know how John's beliefs are manifested in his behaviour. Maybe he is still getting on with his life, being successful in his job, interacting with his family and friends in the normal way, and so on.

But suppose instead that his beliefs have become so all-consuming that he can no longer work? Suppose he now shuns his family and isolates himself? Suppose he confronts his neighbours and threatens them. Suppose he starts planning to commit dangerous acts, such as causing a fire in a public building. By that stage, if not before, surely 'the men in white coats' would be entitled to intervene and consider that John indeed has a mental illness and is in need of treatment.

Now, I have always believed that the business of insisting on diagnostic labels for patients presenting with various forms of mental suffering is fundamentally flawed. Nevertheless it is worth noting here the significance of a person's overt behaviour in determining whether he or she has a mental disorder. This is reflected in the fact that criteria for establishing a psychiatric diagnosis very often include the requirement that 'The disturbance causes clinically significant distress or impairment in social, occupational, or other important areas of functioning' (DSM-IV: Diagnostic and Statistical Manual of Mental Disorders of the American Psychiatric Association, present edition). Hence, in the admittedly unlikely event that John is able to carry on with his life in the normal way, he should not be diagnosed with a mental disorder, nor would he be offered psychiatric treatment.

I think it is probably impossible to construct rules for determining exactly when a 'strange belief' is indicative of a mental disorder. Nevertheless, I do not recall in my professional career any patients of whom it could be seriously suggested that they were having psychiatric treatment just because of their beliefs, though this is not unknown in some countries and at some periods of history.