When does imagery rescripting become a double-edged sword? - Investigating the risk of memory distortion through imagery rescripting in an online Trauma film study.

Imagery Rescripting (ImRs) has proven effective in reducing involuntary emotional memories. However, it is unclear whether and when it may lead to reduced accuracy of voluntary memory. Although previous analogue studies suggest that ImRs does not pose a general risk regarding memory distortion, it can not be ruled out that ImRs could cause memory impairment under certain risk conditions. In our three-day online trauma film study we investigated in a healthy sample (N = 267) whether specific instructions during ImRs as typically provided in clinical practice (i.e., detailed imagery with a sensory focus) increase the risk of memory distortions. Additionally, we examined whether the completeness of the original memory moderates these instruction effects. Contrary to our expectations, a sensory focus during ImRs was associated with higher memory accuracy in a recognition task, independently of the quality of the original memory. These results extend previous findings by suggesting that ImRs does not even impair memory performance when the quality of the original memory is poor and when the production of sensory-rich images is specifically encouraged. Our results question current practices employed to assess witness statement credibility, which are partly based on concerns that trauma-focused interventions like ImRs undermine memory accuracy.

Effects of imagery rescripting and imaginal exposure on voluntary memory.

Trauma-focused imagery-based interventions, such as Imagery Rescripting (ImRs) and Imaginal Exposure (ImE), are effective in reducing involuntary re-experiencing in PTSD. However, it has been suggested that they may impair voluntary memory. This study investigates whether ImRs and ImE distort voluntary memory of an analogue trauma. We presented a trauma film to N = 120 healthy participants (Session 1) and randomly allocated them to one of two intervention conditions (receiving one session of ImRs or ImE) or to a no-intervention control condition (NIC) afterwards (Session 2). Voluntary memory was assessed using a free recall (Sessions 2 and 3), and a cued recall as well as a recognition task (both Sessions 3 and 4). The ImRs and ImE groups did not differ from NIC in the cued recall task and the recognition task. However, ImE (compared to ImRs and NIC) led to an increase in correct reported details in the free recall. In sum, the current findings do not suggest that ImRs or ImE impair voluntary memory.

The dilemma of trauma-focused therapy: effects of imagery rescripting on voluntary memory.

Trauma-focused imagery-based interventions are suspected to alter or even distort declarative voluntary memory of a traumatic event, especially if they involve the active modification of imagery, e.g., as used in imagery rescripting (ImRs). However, systematic research is lacking so far. To investigate whether ImRs modifies voluntary memory of a standardized autobiographical aversive event (Trier Social Stress Test) (Session 1), healthy participants (N = 100) were randomly assigned to either an intervention condition receiving one session of ImRs or to a no-intervention control condition (NIC) (Session 2). Voluntary memory was examined using a free recall (Sessions 2 and 3) and a cued recall (Sessions 3 and 4). Although voluntary memory tended to deteriorate over time, contrary to expectations, this effect was not associated with ImRs. Remarkably, the number of correct details in free recall even improved in ImRs but not in NIC. This challenges the view that ImRs alters voluntary memory.

(When and how) does basic research in clinical psychology lead to more effective psychological treatment for mental disorders?

An important aim of basic research in Clinical Psychology is to improve clinical practice (e.g., by developing novel interventions or improving the efficacy of existing ones) based on an improved understanding of key mechanisms involved in psychopathology. In the first part of this article, we examine how frequently this translation has happened in the past by reviewing all 40 evidence-based psychological interventions recommended in current clinical guidelines for five important (groups of) mental disorders. Results show that only 23% of treatments showed a very strong link between basic research and the development of the intervention, and further 20% showed a strong link. These findings thus suggest that the route from basic research to clinical innovation may not be as strong historically as is commonly assumed. Important challenges for translational research in clinical psychology are reviewed, leading to the introduction of a new framework, and a discussion of possible solutions to overcome these challenges. Suggestions include increased attention to robust and replicable research findings, a stronger focus on experimental psychopathology research to establish causality of psychopathological mechanisms, a more systematic structural integration of basic and applied research in clinical psychology, a stronger emphasis on mechanisms of change and moderators of clinical interventions, increased attention to clinical subgroups, and emphasizing improvements to existing interventions over the development of novel interventions.

Positive Emotion Dysregulation in Posttraumatic Stress Disorder.

Although PTSD is associated with both emotion regulation (ER) difficulties and persistent difficulties experiencing positive emotions, research concerning positive ER in PTSD is still scarce. We aimed to clarify whether PTSD patients show dysfunctional responses to positive emotions and whether positive ER is associated with PTSD symptom severity. PTSD patients (N = 59) were compared to healthy controls (HC, N = 58) with respect to their self-reported regulation of positive and negative emotions. We used the Responses to Positive Affect Questionnaire to assess positive ER and the Difficulties in Emotion Regulation Scale and Response Styles Questionnaire to assess negative ER. PTSD patients showed deficient negative as well as deficient positive ER as compared to HC. Both dampening of positive emotions as well as positive rumination were associated with self-reported symptom severity. Furthermore, dampening contributed to the prediction of PTSD symptom severity beyond depressive symptoms and negative rumination. This study supports and expands previous findings of dysfunctional positive ER in PTSD. Further research is needed to clarify whether deficits in positive ER contribute to the onset and maintenance of PTSD. If so, therapeutic approaches should aim to help PTSD patients build up adequate skills to handle positive emotions in PTSD.

Challenging control over emotions in borderline personality disorder - a tDCS study.

BACKGROUND: Deficient cognitive control (CC) over emotional distraction is a central characteristic of borderline personality disorder (BPD). Reduced activation of the left dorsolateral prefrontal cortex (dlPFC) has been linked to this deficit. This study investigates whether it is possible to ameliorate CC deficits via anodal tDCS over the left dlPFC in BPD. Furthermore, we investigate whether the extent of CC impairment influences how well one responds to tDCS. METHODS: The effect of a single-session tDCS (1 mA for 20 min, reference electrode on the contralateral mastoid bone) to the left dlPFC (F3) on the CC of patients with BPD (N = 20) and healthy control participants (HCs, N = 20) was examined in a double-blinded, balanced randomized, sham-controlled crossover trial. A delayed response working memory task with negative, neutral and positive pictures presented during the delay period was conducted to assess CC. Stimulation was applied simultaneously with the task. RESULTS: Negative pictures caused prolonged response times as compared to a control condition in patients with BPD and HCs. Anodal tDCS to the left dlPFC did not significantly reduce this interference effect in the overall sample. Further analyses showed, however, that participants with impaired CC profited the most from anodal tDCS. In the subgroup of participants who actually showed an interference effect we found the expected significant amelioration of CC under tDCS. CONCLUSIONS: The present study demonstrates that anodal tDCS applied to the left dlPFC improves deficient CC. Thereby, base-level performance moderates tDCS effects. Hence, tDCS might be suitable to support behavioral trainings to enhance CC specifically in people whose impairments in CC are comparably high.

Theory of mind in remitted bipolar disorder: Younger patients struggle in tasks of higher ecological validity.

BACKGROUND: To date, research concerning Theory of Mind (ToM) in remitted bipolar disorder (rBD) has yielded inconclusive results. This may be a result of methodological shortcomings and the failure to consider relevant third variables. Furthermore, studies using ecologically valid stimuli are rare. This study examines ToM in rBD patients, using ecologically valid stimuli. Additionally, the effects of sad mood induction (MI) as well as of age and gender are considered. METHODS: The sample comprises N = 44 rBD patients (rBDPs) and N = 40 healthy controls (HCs). ToM decoding is assessed using the Cambridge Mindreading Face-Voice-Battery (CAM) and ToM reasoning using the Movie for the Assessment of Social Cognition (MASC). Both tasks were divided into two parts to conduct one part with and one without MI. RESULTS: While across the whole sample there was no evidence that rBDPs and HCs differed in ToM decoding or reasoning, in the younger subsample (age < 45) rBDPs performed worse than HCs in ToM decoding. While MI negatively influenced reasoning in both groups, gender had no effect. LIMITATIONS: Most patients in this study had a high level of social functioning, limiting the generalizability of the results. CONCLUSION: As important social steps have to be undertaken before middle-age, the decoding deficits in younger rBDPs might be of particular importance not only for social functioning but also for the course of illness. Furthermore, this age-related deficit may explain the inconclusive findings that have been reported so far.

Impaired cognitive control over emotional material in euthymic bipolar disorder.

BACKGROUND: Previous research suggests that bipolar disorder (BD) is characterized by deficits in cognitive control (CC). Impaired CC has been found in high-risk samples and is associated with the maintenance of BD symptoms. It remains unclear, however, whether BD is characterized by a general deficit in CC or by a deficit that is specifically related to the processing of emotional material. METHODS: The sample consisted of 42 remitted bipolar patients and 39 healthy controls (HC). We examined whether BD individuals display impaired CC when confronted with negative as well as positive material using an arithmetic inhibition task that required inhibition of pictorial stimulus material. RESULTS: Whereas both groups showed difficulties in exerting CC over negative material, only BD individuals exhibited deficient CC over positive material. LIMITATIONS: Even though we intended the negative and positive pictures in the arithmetic inhibition task to be similarly arousing, participants in the current study rated the negative compared to the positive pictures as more arousing. CONCLUSIONS: BD is associated with impaired CC when processing emotional - especially positive - stimuli even when patients are in remission. Possible implications of this deficit especially for emotion regulation are discussed.

Facial emotion recognition, theory of mind and the role of facial mimicry in depression.

BACKGROUND: This study examined whether acutely (aMDD) and remitted depressed patients (rMDD) show deficits in the two aspects of social cognition - facial emotion recognition (FER) and reasoning - when using ecologically valid material. Furthermore, we examined whether reduced facial mimicry mediates the association between depressive symptoms and FER, and whether FER deficits and reasoning deficits are associated. METHOD: In 42 aMDD, 43 rMDD, and 39 healthy controls (HC) FER was assessed using stimuli from the Amsterdam Dynamic Facial Expression Set, reasoning by the Movie for the Assessment of Social Cognition. Furthermore, the activity of Zygomaticus Major and Corrugator supercilii were recorded. RESULTS: aMDD recognized happy faces less accurately, were less confident recognizing happiness and anger and found it more difficult to recognize happiness, anger and fear than HC. rMDD were less confident recognizing anger and found it more difficult to recognize happiness, anger and fear than HC. Reduced mimicry did not explain FER deficits. aMDD but not rMDD showed impaired reasoning. LIMITATIONS: The stimulus material was comparably easy to decode. Therefore, it is possible that the FER deficits of aMDD and rMDD patients are more pronounced than demonstrated in this study. CONCLUSIONS: aMDD show deficits in FER and reasoning, whereas rMDD only show mild impairments in the recognition of emotional expressions. There must be other processes - besides mimicry - that serve the accurate recognition of emotional facial expressions.

Targeting the biased brain: non-invasive brain stimulation to ameliorate cognitive control.

Non-invasive brain stimulation has become important for the investigation of healthy and impaired neuronal functioning. Moreover, non-invasive brain stimulation has emerged as a new means of psychiatric treatment, although the mechanisms of action are still not understood and the optimal mode of application is still under development. Dysfunctional cognitive control is a central characteristic of various psychiatric disorders and is associated with dysregulations of prefrontal cortex activity and biased information processing. With non-invasive brain stimulation, enhancement and reduction of prefrontal cortex activity were shown to ameliorate and impair cognitive control, respectively. These findings suggest a neurocognitive mechanism of therapeutic effects and that non-invasive brain stimulation can be combined with training to target dysfunctional cognitive control and related clinical symptomatology. Nevertheless, the intra-individual and inter-individual diversity of neurocognitive processes, the multiplicity of possible stimulation parameters, and the complexity of interactions between those factors pose considerable challenges for interpretation of these findings and their clinical application.

Keep calm and carry on: improved frustration tolerance and processing speed by transcranial direct current stimulation (tDCS).

Cognitive control (CC) of attention is a major prerequisite for effective information processing. Emotional distractors can bias and impair goal-directed deployment of attentional resources. Frustration-induced negative affect and cognition can act as internal distractors with negative impact on task performance. Consolidation of CC may thus support task-oriented behavior under challenging conditions. Recently, transcranial direct current stimulation (tDCS) has been put forward as an effective tool to modulate CC. Particularly, anodal, activity enhancing tDCS to the left dorsolateral prefrontal cortex (dlPFC) can increase insufficient CC in depression as indicated by a reduction of attentional biases induced by emotionally salient stimuli. With this study, we provide first evidence that, compared to sham stimulation, tDCS to the left dlPFC enhances processing speed measured by an adaptive version of the Paced Auditory Serial Addition Task (PASAT) that is typically thwarted by frustration. Notably, despite an even larger amount of error-related negative feedback, the task-induced upset was suppressed in the group receiving anodal tDCS. Moreover, inhibition of task-related negative affect was correlated with performance gains, suggesting a close link between enhanced processing speed and consolidation of CC by tDCS. Together, these data provide first evidence that activity enhancing anodal tDCS to the left dlPFC can support focused cognitive processing particularly when challenged by frustration-induced negative affect.

Emotional Distraction and Bodily Reaction: Modulation of Autonomous Responses by Anodal tDCS to the Prefrontal Cortex.

Prefrontal electric stimulation has been demonstrated to effectively modulate cognitive processing. Specifically, the amelioration of cognitive control (CC) over emotional distraction by transcranial direct current stimulation (tDCS) points toward targeted therapeutic applications in various psychiatric disorders. In addition to behavioral measures, autonomous nervous system (ANS) responses are fundamental bodily signatures of emotional information processing. However, interactions between the modulation of CC by tDCS and ANS responses have received limited attention. We here report on ANS data gathered in healthy subjects that performed an emotional CC task parallel to the modulation of left prefrontal cortical activity by 1 mA anodal or sham tDCS. Skin conductance responses (SCRs) to negative and neutral pictures of human scenes were reduced by anodal as compared to sham tDCS. Individual SCR amplitude variations were associated with the amount of distraction. Moreover, the stimulation-driven performance- and SCR-modulations were related in form of a quadratic, inverse-U function. Thus, our results indicate that non-invasive brain stimulation (i.e., anodal tDCS) can modulate autonomous responses synchronous to behavioral improvements, but the range of possible concurrent improvements from prefrontal stimulation is limited. Interactions between cognitive, affective, neurophysiological, and vegetative responses to emotional content can shape brain stimulation effectiveness and require theory-driven integration in potential treatment protocols.

Induction of a depression-like negativity bias by cathodal transcranial direct current stimulation.

Cognitive control (CC) over emotional distraction is of particular importance for adaptive human behaviour and is associated with activity in the left dorsolateral prefrontal cortex (dlPFC). Deficient CC, e.g., presenting as negativity bias, has been suggested to underlie many of the core symptoms of major depression (MD) and is associated with impairments of dlPFC function. Correspondingly, enhancement of dlPFC activity with anodal transcranial direct current stimulation (tDCS) can ameliorate these impairments in patients with MD. Here, we tested the hypothesis that a reduction of dlPFC activity by cathodal tDCS induces CC deficits, thus triggering a depression-like negativity bias in healthy subjects. Twenty-eight individuals participated in a double-blinded, balanced randomized crossover trial of cathodal (1 mA, 20 min) and sham tDCS applied to the left dlPFC. To assess CC we conducted a delayed response working memory (DWM) task and an arithmetic inhibition task (AIT) with pictures of varying valent content (negative, neutral, positive) during and immediately after stimulation. Cathodal tDCS led to impaired CC specifically over negative material as assessed by reduced response accuracy in the DWM and prolonged response latency in the AIT. Hence, the current study supports the notion that left dlPFC is critically involved in CC over negative material. Together with previously reported beneficial anodal effects, it indicates that the hypoactivation of left dlPFC causes deficits in CC over negative material, which is a possible aetiological mechanism of depression.

Cognitive emotion regulation in euthymic bipolar disorder.

BACKGROUND: Based on findings indicating increased stress reactivity and prolonged stress recovery in individuals with bipolar disorder (BD), it has been proposed that emotion regulation (ER) deficits lie at the core of this disorder. Recent studies show an increased use of maladaptive ER strategies and a decreased use of adaptive ER strategies in BD. Whether this pattern is merely a correlate of affective episodes or might be a stable characteristic of BD, however, remains to be explored. In addition, it is unclear whether these deficits in ER are specific to people with a history of BD. METHODS: We examined whether euthymic BD individuals differ from healthy controls (HC) and individuals with a history of Major Depressive Disorder (MDD) with respect to the cognitive ER strategies they habitually use (CERQ) in response to negative affect. The sample consisted of 42 bipolar patients, 43 patients with MDD and 39 HC. RESULTS: Compared to HC, euthymic BD and MDD individuals reported increased use of rumination, catastrophizing, and self-blame alongside decreased use of positive reappraisal, and putting into perspective. No differences were found between BD and MDD groups. LIMITATIONS: These findings are based on self-reports reflecting the habitual use of ER-strategies. The use of more objective methods and the examination of the spontaneous use of ER-strategies in euthymic BD would be desirable. CONCLUSIONS: Deficits in the habitual use of ER strategies may characterize BD and MDD individuals even outside of an acute episode and thereby play a role in the recurrence of affective disorders.

Amelioration of cognitive control in depression by transcranial direct current stimulation.

BACKGROUND: Deficient cognitive control over emotional distraction is a central characteristic of major depressive disorder (MDD). Hypoactivation of the dorsolateral prefrontal cortex (dlPFC) has been linked with this deficit. In this study, we aimed to enhance the activity of the dlPFC in MDD patients by anodal transcranial direct current stimulation (tDCS) and thus ameliorate cognitive control. METHODS: In a double-blinded, balanced, randomized, sham-controlled crossover trial, we determined the effect of a single-session tDCS to the left dlPFC on the cognitive control in 22 MDD patients and 22 healthy control subjects. To assess the cognitive control, we used a delayed response working memory task with pictures of varying content (emotional vs. neutral) presented during the delay period. RESULTS: Emotional pictures presented during the delay period impaired accuracy and response time of patients with MDD, indicating an attentional bias for emotional stimuli. Anodal tDCS to the dlPFC was associated with an enhanced working memory performance both in patients and control subjects. Specifically in subjects with MDD, the attentional bias was completely abolished by anodal tDCS. CONCLUSIONS: The present study demonstrates that anodal tDCS applied to the left dlPFC improves deficient cognitive control in MDD. Based on these data, tDCS might be suitable to support the effects of behavioral training to enhance cognitive control in MDD.

Is impaired set-shifting a feature of "pure" anorexia nervosa? Investigating the role of depression in set-shifting ability in anorexia nervosa and unipolar depression.

Impaired set-shifting has been reported in patients with anorexia nervosa (AN) and in patients with affective disorders, including major depression. Due to the prevalent comorbidity of major depression in AN, this study aimed to examine the role of depression in set-shifting ability. Fifteen patients with AN without a current comorbid depression, 20 patients with unipolar depression (UD) and 35 healthy control participants were assessed using the Trail Making Test (TMT), the Wisconsin Card Sorting Test (WCST) and a Parametric Go/No-Go Test (PGNG). Set-shifting ability was intact in patients with AN without a comorbid depression. However, patients with UD performed significantly poorer in all three tasks compared to AN patients and in the TMT compared to healthy control participants. In both patient groups, set-shifting ability was moderately negatively correlated with severity of depressive symptoms, but was unrelated to BMI and severity of eating disorder symptoms in AN patients. Our results suggest a pivotal role of comorbidity for neuropsychological functioning in AN. Impairments of set-shifting ability in AN patients may have been overrated and may partly be due to comorbid depressive disorders in investigated patients.

Specificity of jumping to conclusions and attributional biases: a comparison between patients with schizophrenia, depression, and anorexia nervosa.

INTRODUCTION: The knowledge of the specificity of cognitive biases in psychiatric disorders is important in order to develop disorder-specific cognitive models and therapies. This cross-sectional study aimed to investigate the specificity of jumping to conclusions (JTC) and attributional biases (AB) for patients with schizophrenia. METHODS: Twenty patients with paranoid schizophrenia were compared with patients with depression (n=20) and with anorexia nervosa (n=15) and nonclinical controls (n=55). All participants were administered a modified version of the beads task (JTC), a revised German version of the Internal, Personal, and Situational Attributions Questionnaire (AB), and several symptom and neurocognitive measures. RESULTS: The proportion of patients with JTC bias in the schizophrenia group was, at the descriptive level, higher than in the depression and the anorexia groups. Regarding AB, the schizophrenia group showed a significantly stronger externalising but not personalising bias than the clinical control groups. Neither JTC nor attributional biases were significantly associated with delusions in general or persecutory delusion. CONCLUSIONS: We found evidence for the specificity of an externalising bias for paranoid schizophrenia. Concerning JTC bias the evidence was less clear. Whether the modification of those biases through psychological interventions would have an effect on psychopathology should be investigated in the context of clinical trials.

I can see what you feel, but I can't deal with it: Impaired theory of mind in depression.

BACKGROUND: Even though unipolar depression is associated with considerably impaired social functioning, only a few studies so far have investigated Theory of Mind (ToM) abilities of unipolar depressed patients. Therefore, the main goal of this study is to examine whether depressed patients are impaired in their ToM as compared to healthy controls. Thereby, both aspects of ToM, i.e. decoding and reasoning, are examined separately. METHODS: Acutely depressed patients with unipolar affective disorder (n=24) and healthy controls (n=20) were examined with the 'Reading the Mind in the Eyes Test' (RMET) and the 'Movie for the Assessment of Social Cognition' (MASC) to address the two aspects of ToM. RESULTS: Patients compared to controls did not show impaired decoding ability in the RMET, but did show deficits in integrating contextual information about other people (reasoning) in the MASC. This impairment is independent of the mental state modality that had to be judged (emotional vs. cognitive). LIMITATIONS: Possible differences between the diagnostic subgroups of depression, which play an important role in clarifying the opposing results concerning the association between ToM abilities and depression in the existing literature, have not been examined. CONCLUSIONS: It is possible that the low level of social functioning associated with depression can be ascribed partially to a ToM deficit and should be addressed in the treatment of depression.

The Hypomania Checklist-32 and the Mood Disorder Questionnaire as screening tools--going beyond samples of purely mood-disordered patients.

BACKGROUND: Bipolar disorders are often not recognized. Several screening tools have been developed, e.g., the Hypomania Checklist-32 (HCL-32) and the Mood Disorder Questionnaire (MDQ) to improve this situation. Whereas the German HCL-32 has been used in non-clinical samples, neither the HCL-32 nor the MDQ has been validated in German samples of mood-disordered patients. Additionally, hardly any prior study has included patients with non-mood disorders or has considered potential effects of comorbid conditions. Therefore the goal of this study was to test the validity of both scales in a diverse patient sample while also taking into account psychiatric comorbidity. METHOD: A multi-site study was conducted involving seven centers. Patients (n=488) completed the HCL-32 and MDQ and were independently interviewed with the Structured Clinical Interview for DSM (SCID). RESULTS: Sensitivity for bipolar I was similar for HCL-32 and MDQ (.88 and .84) but slightly different for bipolar II (.90 and .83), specificity, however, was higher for MDQ. In general, a comorbid condition led to increased scores in both tools regardless of whether the primary diagnosis was bipolar or not. LIMITATIONS AND DISCUSSION: Although we included not just mood-disordered patients, detailed subgroup analyses for all diagnostic categories were not possible due to sample sizes. In summary, HCL-32 and MDQ seem fairly comparable in detecting bipolar disorders although their effectiveness depends on the goal of the screening, psychiatric comorbidity, and potentially the setting.

Misdiagnosing bipolar disorder--do clinicians show heuristic biases?

BACKGROUND: Bipolar disorders (BD) are often misdiagnosed. Clinicians seem to use heuristics instead of following the recommendations of diagnostic manuals. Bruchmüller and Meyer (2009) suggest that 'reduced sleep' is a prototypic criterion that increases the likelihood of a bipolar diagnosis. This study examines if this criterion specifically elevates the likelihood of a bipolar diagnosis or if the finding of the study mentioned above is rather due to the total number of criteria. Furthermore, we want to replicate the finding that patients offering a causal explanation for their manic symptoms are misdiagnosed more often. Additionally, we examine therapeutic attributes that might influence diagnostic decisions as well as treatment consequences following a (mis-)diagnosis. METHODS: 204 Psychotherapists were presented with a case vignette describing someone with a BD and were asked to make a diagnosis. Symptoms and the total number of criteria varied systematically within the vignettes but each still fulfilled enough diagnostic criteria to be diagnosed as bipolar. RESULTS: Almost 60% of the clinicians made misdiagnoses. A correct diagnosis did not depend on the specific criterion of 'reduced sleep' but on the total number of criteria. The causal explanation as well as therapeutic attributes did not significantly influence diagnostic decisions. However, the study showed that a misdiagnosis can lead to severe consequences concerning the treatment recommended by clinicians. LIMITATIONS: The validity of case vignettes is discussible. CONCLUSIONS: It seems as if specific symptoms might not be of so much relevance as assumed. Instead, clinicians seem to follow the additive model when making diagnoses.