This study follows a group of 174 young people with new onset of schizotypal symptoms and examines factors which may lead to conversion to psychosis. These prodromal subjects were screened for symptoms and later given the Structured Clinical Interview of DSM-III-R at one year, two years and ten years post onset. We also included the Paranoia Scale of Fenigstein and Vanable and the Scale for Thought, Language and Communications of Andreasen in all interviews. Our analysis found that the addition of scales for paranoia and thought disorder enhanced prediction of conversion to psychosis and long term outcome. The early occurrence of ideas of reference and poverty of thought appear to be significant predictors of future deterioration even when considered among other high-risk variables.
The ability to predict the outcome of an illness has always been an important part of medical science. Similarly, many psychiatric syndromes have mild symptoms that appear prior the development of major illness. The use of prodromal terminology was introduced by Mayer-Gross in the early 20th century [1]. In recent years there has been increased interest in prognostic features of the schizophrenic prodroma [1], [2], [3], [4], [5], [6], [7], [8] and [9]. The factors which predict conversion to psychosis are now the focus of considerable new research [2]. Several factors such as high genetic loading and substance abuse are known to be associated with poor outcome for many patients with prodromal symptoms [2], [3], [4], [5], [6] and [7]. Early onset of paranoia and thought disorder has also been noted as factors which may predict conversion into psychosis [8], [9] and [10]. The use of psychiatric symptoms to examine the patient’s progress has valuable clinical implications. With the development of prevention models in psychiatry, the ability to predict the course of an illness early on is gaining greater clinical importance [7], [8], [9] and [11]. The use of valid and reliable instruments to rate symptoms is, therefore, critical for proper longitudinal study of clinical syndromes over time. By using operational criteria in prospective work, the relative risk associated between early symptoms and later outcome can be assessed with a higher degree of precision.
Paranoid thinking has long been suspected to be a risk factor for the development of schizophrenia, yet it has not been well studied with operational criteria until recently [6], [9], [12] and [13]. Since unusual notions are found in normal populations and in a variety of syndromes [13], [14], [15] and [16], it is important to determine which cases are benign and which are more likely to deteriorate. It is, therefore, vital to ascertain which individuals with peculiar thinking are most at risk for decompensation. The Scale for Thought, Language and Communication (TLC) of Andreasen has been a very reliable standard for the evaluation of thought disorder for quite some time [17] and was chosen as one scale for examination of these problems. Fenigstein and Vanable have developed a scale for measuring paranoia that is both reliable and valid. This was used to examine paranoid thinking in detail [18]. By inclusion of these detailed scales, along with other measures, we hoped to determine the relative value of thought disorder and paranoia in the prediction of prognosis in early cases of prodromal illness.
This project was designed to examine the effect of early symptomatology on both conversion to psychosis and also on long term prognosis. We wanted to assess the relative value of symptomatic and demographic variables at one year, two year and ten year intervals after the first onset of psychological impairment (Table 1, Table 2, Table 3, Table 4, Table 5 and Table 6). We examined symptoms in subjects with the onset of new psychiatric symptoms (in the first 6 months) and followed up to see how these people progressed over the next ten years. Our efforts were concentrated on new cases of emotional illness regardless of their diagnosis. We thought that the addition of specific scales for thought disorder and paranoia would enhance prediction for conversion and later outcome.
