مقدمه: دیدگاهی جهانی به افکار مزاحم و ناخواسته

Because of Rachman and de Silva׳s (1978) influential research on normal and abnormal obsessions, it is now a basic tenet of cognitive behavioral theories (CBT) that clinical obsessions have their origins in the normal intrusive thought phenomena that characterizes the stream of consciousness. However much of the empirical research on unwanted intrusive thoughts has utilized retrospective self-report questionnaires that have weak construct validity and the samples have been drawn primarily from Western European and North American populations. To enhance the measurement precision and investigate the universality of unwanted intrusions, a structured intrusive thoughts interview was developed and administered to 777 nonclinical individuals drawn from 13 countries. The three papers in this special issue present findings based on this large data set. Together it was found that unwanted intrusive thoughts are reported by the majority of individuals in all countries, that significant cross-cultural differences are apparent in primary intrusive thought content, that faulty appraisals and confrontational control strategies are related to the distress of intrusions, and that the frequency of dirt/contamination, doubt, and miscellaneous intrusions are specifically related to obsessive compulsive symptom distress. The authors discuss these findings in terms of their consistency with predictions derived from the CBT perspective on obsessions. The special issue concludes with a discussion paper by Professor Jack Rachman, originator of the obessional intrusions concept.

This year marks the 36th anniversary of Rachman and de Silva׳s (1978) seminal article that introduced the concept of unwanted intrusive thoughts as a potential etiological factor in the development of obsessive compulsive disorder (OCD). Their paper reported on three studies that sought to determine whether healthy, nonclinical individuals experience unwanted thoughts, images or impulses that are similar in content to clinical obsessions (i.e., thoughts of contamination, doubt, aggression, sexuality, etc.). In the first study based on an intrusive thoughts questionnaire 99/124 (80%) nonclinical individuals reported fairly frequent unwanted thoughts or images involving obsessional content, although they were considered fairly easy to dismiss. The second study consisted of a detailed interview of intrusive thoughts conducted on 40 nonclinical individuals and 8 patients with OCD. A list of 23 obsessions from the clinical sample and 58 obsessive-like intrusions from the nonclinical individuals were reproduced in the article and have since become the basis of numerous self-report measures of intrusive thoughts. Comparison between the clinical and nonclinical samples revealed similarities in thought content, although the OCD patients reported greater frequency, discomfort and difficulty controlling their obsessions. In the third study OCD patients and nonclinical participants were asked to repeatedly form their obsession or intrusive thought. Habituation was evident in both samples, although the nonclinical group had more difficulty forming their intrusion upon request than the OCD patients. Although Rachman and de Silva׳s (1978) findings raised many questions about the nature of intrusive thoughts, it also provided the first empirical evidence that obsessions might have their origins in the normal thought processes that characterize the stream of consciousness. The conceptual significance of “normal obsessions” was subsequently emphasized in Rachman and Hodgson׳s (1980) text, Obsessions and Compulsions, which in many respects provides the theoretical underpinnings for contemporary cognitive-behavioral (CB) models of OCD. In their chapter entitled An Anatomy of Obsessions, the occurrence of unwanted, unacceptable intrusive thoughts or images initiated a process of faulty meta-cognitive appraisal and control efforts that could spiral into the development of obsessions. Later publications elaborating on a CBT model of obsessions and compulsions also reiterated the occurrence of mental intrusions as a key determinant in the pathogenesis of obsessions (e.g., Clark, 2004, Freeston et al., 1996, Rachman, 1997, Rachman, 1998, Salkovskis, 1985 and Salkovskis, 1989). Today the universality of obsession-related intrusive thoughts, images and impulses is a central tenet of CBT explanations for the development of obsessions. While the conceptual significance of the Rachman and de Silva (1978) publication cannot be overstated, their work has also had a significant impact on empirical research on unwanted intrusions. In the last three decades research on intrusions has taken two broad pathways; the most common approach is questionnaire based, whereas the other is more experimental, examining the impact of intentional mental control efforts on unwanted intrusive thoughts. These two broad research pathways are represented in the first and third studies reported in the Rachman and de Silva (1978) publication. Interestingly there has been little research that has employed the interview format; a neglect that we think is serious given the complexity of intrusive thoughts. There are important conceptual and methodological weaknesses that have been raised with questionnaire and experimental measurement of unwanted intrusive thoughts. Questionnaire measures of intrusions present individuals with a predetermined list of thought statements which respondents are then instructed to rate for frequency of occurrence. However concerns have been raised about the veridicality of these item responses (Brown & Clark, 2014). When individuals indicate that they frequently experience an unwanted intrusive thought by endorsing an item statement, does this reflect their actual memory of specific thought occurrences, or might it reflect an emotional state or self-identity that is congruent with the item content (Glass & Arnkoff, 1997)? In addition the content validity of many intrusive thought questionnaires is problematic because they can contain a broad range of negative thought content that often includes general anxiety and depressive thought content (Clark & Purdon, 1995). As well the lists of intrusions are always predetermined so how well these pre-established items represent the intrusive thought content of specific individuals is doubtful. Rachman (1981) has noted that unwanted mental intrusions are often quite idiosyncratic and triggered by external cues. Questions have also been raised about the specificity and discriminative validity of intrusive thoughts questionnaires (Julien, O’Connor, & Aardema, 2007). These are fundamental questions about the construct validity of retrospective self-report of unwanted intrusions that leave us uncertain about the interpretability of a high score on such measures. When a person indicates that s/he frequently has an intrusion (e.g., “I have unwanted intrusive thoughts, images or impulses of verbalizing something rude or embarrassing that would hurt a person׳s feelings”), is this based on memories of actual thought occurrences, recalling times when feeling anxious about one׳s verbal interaction, a single recent experience of “embarrassed verbalization”, or a self-identity that acknowledges you are the type of person who is concerned about your impact on others? In sum questionnaires may not be the most accurate method for assessing people׳s actual experience of unwanted intrusive thoughts. Unfortunately experimental approaches to the investigation of unwanted mental intrusions and their control also have significant drawbacks. The first problem is ecological validity. When an individual is brought into a laboratory setting and asked to produce an intrusive thought, it is no longer intrusive. The intentional production of the thought is no longer unwilful and so lacks generalizability to the spontaneous, unintended intrusions that occur in the natural world. As well, a diffusion of responsibility occurs such that the participant can now attribute responsibility to the experimenter for the generation of the intrusion rather than the self. This transfer of responsibility to the experimenter could significantly affect the participant׳s appraisal of the intrusive thought. Even if the intrusion is induced, difficulties arise because it may be difficult to ensure that the induction was successful across all research participants. Finally, the control of unwanted negative thoughts under controlled laboratory conditions for very brief time periods will be quite different from the experience of repeated unwanted intrusions over an extended period of time in a context-rich, everchanging naturalistic setting. Thus the findings derived from laboratory-contrived intrusive phenomena raise questions about their relevance to the spontaneous, distressing intrusive thoughts, images and impulses that can “haunt” individuals in their everyday life.