- On the Impossibility of Defining Delusions
Consider these vignettes: A thirty-three year-old Oxford University graduate who had worked as a journalist related this story. He had no previous psychiatric history but at times drank heavily. There was no family history. He was asked to review a book on spirituality, which he agreed to do. While in his bedroom reading, he suddenly became aware of God’s presence. A phrase in the book took on special significance, and he read it over and over. He felt “supremely happy.” Although no words were spoken, he believed to have seen his “Savior in the spirit.” Soon all his friends were aware of this sudden conversion. The next day, he got drunk, much to everyone’s disappointment. He later interpreted this as temptation from Satan and subsequently “surrendered” his life to God.
A twenty-four-year-old ex-marine with no past or family psychiatric history was sitting in a pub, “pondering the question of love,” when it suddenly came to him that “love is God.” He immediately decided that he should devote himself to God and the Bible and that he should renounce sex and alcohol. Subsequently, while at the theater with his girlfriend, he felt as if the two of them had merged and that he had seen a vision of heaven. At this time he felt he should devote his life to a struggle against the forces of darkness, which produced vibrations in his genitals. He became a lay preacher.
While going on to discuss delusions, let us, in the meantime, indulge in a game taken from a popular television sports quiz, “What happened next?”
The delusion is the hallmark of psychosis. If a clinician notes the presence of a delusion in a patient, this has enormous implications for diagnosis and treatment, as well as complex notions concerning responsibility, prediction of behavior, etc. Yet despite the facade created by psychiatric textbooks, there is no acceptable (rather than accepted) definition of a delusion. Most attempted definitions begin with “false belief,” and this is swiftly amended to an unfounded belief to counter the circumstance where a person’s belief turns out to be true. Then caveats accumulate concerning the person’s culture and whether the beliefs are shared. Religious beliefs begin to cause problems here and religious delusions begin to create major conflicts (see Kirov et al. 1998 for a recent study of religiosity and insight in psychosis, and Smith 1968 for a lucid discussion of definitions). The beleaguered psychopathologist then falls back on the “quality” of the belief—the strength of the conviction in the face of contradictory evidence, the “incorrigibility,” the personal commitment, etc. Here, the irrationality seen in “normal” reasoning undermines the specificity of these characteristics for delusions (see Kemp et al. 1996) as does the variable conviction and fluctuating insight seen in patients with chronic psychoses who everyone agrees are deluded (David 1990; Amador [End Page 17] et al. 1994). Finally we have the add-ons: the distress caused by the belief, its preoccupying quality, and its maladaptiveness generally, again, sometimes equally applicable to other beliefs held by non-psychotic fanatics of one sort or another. In the end we are left with a shambles.
Why are most psychiatrists not troubled by this in their daily work? Most of us agree that believing you are in touch with God is not necessarily a delusion (unless you are diagnosed as schizophrenic on other criteria). Most of us agree that believing that Elvis is still alive or that you have been abducted by aliens is not a delusion (it’s just daft); nor is denying the fact that you are dangerously thin while claiming to be overweight (it is merely an “overvalued idea”), but we struggle to say why. If a man is “convinced” that he has cancer despite “incontrovertible evidence” given to him by a physician, he is likely to be labeled “hypochondriacal” rather than deluded; if he says his skull is empty, the term nihilistic delusion is likely to be invoked. A person who says it is “as if” his skull is empty, or full of cotton wool, is describing the core feature...