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To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.brat.2009.04.013 Byline: Peter F. Lovibond (a), Christopher J. Mitchell (a), Erin Minard (a), Alison Brady (a), Ross G. Menzies (b) Abstract: A laboratory autonomic conditioning procedure was used to establish fear conditioning in human participants by pairing neutral stimuli with electric shock. Participants were also trained to make a button-press response to avoid shock. A target fear stimulus was then extinguished by presenting it without shock. The experimental group was given the opportunity to make the avoidance response during extinction whereas the control group was not. When the fear stimulus was tested without the response available, the control group showed normal extinction of both shock expectancy ratings and skin conductance responses, but the experimental group showed 'protection from extinction': they continued to give high expectancy ratings and strong skin conductance responses. We interpret this effect as analogous to the role of within-situation safety behaviours in preserving threat beliefs during exposure therapy for anxiety disorders. The results support a cognitive account of learning and anxiety. The procedure provides a potential laboratory model for further examination of the cognitive and neural mechanisms underlying anxiety and its reduction. Author Affiliation: (a) School of Psychology, University of New South Wales, Sydney NSW 2052, Australia (b) Discipline of Behavioural and Social Sciences in Health, University of Sydney, Australia Article History: Received 8 December 2008; Revised 16 April 2009; Accepted 29 April 2009

Purpose: The aims of the present study were to (a) examine the rate of social phobia among adults who stutter, (b) study the effects of speech restructuring treatment on social [...]

Two research groups have raised the possibility that magical ideation may be a fundamental feature of obsessive-compulsive disorder. It has been proposed to underlie thought action fusion and superstitious beliefs. In this study, the Magical Ideation scale, the Lucky Behaviours and Lucky Beliefs scales, the Thought Action Fusion--Revised scale, the Padua Inventory, and the Obsessive Compulsive Inventory Short Version were completed by 60 obsessive compulsive patients at a hospital clinic. Of all the measures, the Magical Ideation (MI) scale was found to be the most strongly related to obsessive compulsive symptoms. Large and significant relationships between MI scores and the measures of OCD were obtained even when alternative constructs (Lucky Behaviours, Lucky Beliefs, Thought Action Fusion Revised scales) were held constant. No other variable remained significantly related to the Obsessive Compulsive Inventory--Short Version when magical ideation scores were held constant. The findings suggest that a general magical thinking tendency may underpin previous observed links between superstitiousness, thought action fusion and OCD severity. Keywords: Obsessive-compulsive disorder; Magical ideation; Thought action fusion; Superstition; Schizotypy

It is well established that many patients with obsessive-compulsive disorder have covert, or internal, compulsions. Empirical studies of this phenomenon, however, are limited. The present study followed the paradigm developed by Rachman and his colleagues for the study of overt compulsions. Patients with urges to carry out covert compulsions underwent an experimental procedure in which their compulsive urges were provoked, followed by a period of response prevention. The strength of the compulsive urges and associated discomfort were monitored. There was marked, and relatively rapid, spontaneous decay of both the compulsive urges and the discomfort. Implications of these results are discussed. Keywords: Covert compulsions; Spontaneous decay; Obsessive-compulsive disorder

This study investigated the long-term efficacy of three 45-minute sessions of live graded exposure, computer-aided vicarious exposure, or progressive muscle relaxation placebo for the treatment of spider phobia, and is a follow-up of the results previously reported by Gilroy, Kirkby, Daniels, Menzies, and Montgomery (2000). Forty-two out of 45 participants were assessed, using both subjective and behavioral assessments, at a mean of 33 months after completing treatment. The assessor was unaware of treatment group. Results showed significant improvement from pretreatment to 33-month follow-up across a range of measures in all treatment groups, although the group by time interaction was not statistically significant. Between 3-month and 33-month follow-up, no significant change was observed in any group, indicating sustained long-term improvement. The results support previous reports of the long-term efficacy of live graded exposure and indicate similar durable treatment outcome effects for computer-aided vicarious exposure.

Purpose: This study was designed to answer three questions. (a) Does percentage of syllables stuttered (%SS) differ between standard and challenge phone calls. (b) Does anxiety differ between standard and challenge phone calls. (c) Is there a relationship between %SS and anxiety during standard and challenge phone calls? Method: Participants were 230 adults diagnosed with stuttering, who were participants from five clinical trials. Each participant received two 10-min phone calls at pretreatment and a further two phone calls 6 months or 20 weeks postrandomization. One phone call was standard, and the other presented challenge: occasionally disagreeing with, interrupting, and talking over participants, or asking for clarification of their views. Results: Statistically significant, but clinically minor, increases of %SS and anxiety occurred during the challenge phone calls. There was a statistically significant association between %SS and anxiety. Conclusions: Variable phone call procedures to assess stuttering severity in clinical trials are not likely to spuriously inflate or deflate treatment outcomes to a clinically important extent. Regardless, the present results suggest that there is statistical merit in controlling the nature of phone calls during clinical trials with the simple and replicable method developed in this report. Additionally, there is procedural merit in the challenge phone call procedure; it is a more valid representation of the challenges of everyday speech than the standard procedure. However, a disadvantage of the challenge phone call procedure is the practical issues associated with its use. The clinical and theoretical applications of the results are discussed. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this laboratory study was to investigate whether rhythmic speech was primarily responsible for stuttering reductions in four school-aged children after the instatement stage of the Westmead Program of syllable-timed speech (STS) intervention. The study was designed to inform further development of the program. Reduction in variability of vowel duration is a marker of STS, and it was predicted that this would be present in the children's conversational speech after Stage 1 of the program if they were using STS. To strengthen such a finding, it was also predicted that there would be no reduction in articulation rate, sentence complexity, and utterance length after treatment, as there is evidence that reductions in these can reduce stuttering. Perceptual judgments of speech quality after treatment were also made by independent listeners. Method: Participants were four children, ages 8–11 years, who completed Stage 1 of an STS program and whose stuttering had reduced significantly. Pre-treatment (PRE) and post-treatment (POST) within-clinic audio-visual recordings of conversational speech were analysed for percentage of syllables stuttered, variability of vowel duration, articulation rate, and length and complexity of utterance. Four blinded listeners made perceptual judgments of speech quality in the POST recordings. Result: Recordings of all children showed that variability of vowel duration clearly reduced from the PRE to POST speech samples. Importantly, articulation rate and language use were not compromised. Some possible indicators of rhythmicity were identified in one child in the perceptual study. Conclusion: The findings suggest that STS was primarily responsible for the clinically significant reductions in stuttering after Stage 1 of the program. There is an urgent need for more evidence-based interventions for stuttering in this age group and further development of STS interventions is warranted. [ABSTRACT FROM AUTHOR]

Alleged differences between associative and non-associative perspectives are sometimes more apparent than real. The non-associative model describes a pathway to fear that is complementary to associative pathways. It does not seek to usurp conditioning models as applied to evolutionary-neutral fear. We discuss vexing definitional issues surrounding what qualifies as a conditioning event and what characterises the non-associative pathway. Genetic findings are shown to be consistent with the non-associative model of fear. Following discussion of the relation between stress-diathesis models and the non-associative position we conclude by urging a developmental, life-course approach to the understanding of fear acquisition.

It is axiomatic that the capacity to experience fear is adaptive, enabling rapid and energetic response to imminent threat or danger. Despite the generally accepted utility of functional fear, the nature of maladaptive fear remains controversial. There is still no consensus about how specific fears and phobias are acquired and modulated. Two major schools of thought are apparent: those suggesting dysfunctional fear arises largely as the result of associative-conditioning processes versus those who favour more biologically based etiological explanations. In this regard, the non-associative model of fear acquisition postulates the existence of a limited number of innate, evolutionary-relevant fears, while emphasising conditioning modes of onset for evolutionary-neutral fears. Recent retrospective and longitudinal studies have tested predictions from the non-associative model. In general, findings support non-associative hypotheses and are difficult to reconcile with neo-conditioning explanations of fear acquisition. These data suggest that four pathways to fear may provide the most parsimonious theory of fear etiology. The theoretical and practical implications of adding a fourth, non-associative path to Rachman's (Behav. Res. Ther. (1977) 15, 375-387) three `associative' pathways are discussed. Unresolved issues requiring further investigation are considered.

A longitudinal examination of the relation between separation experiences and the development of separation anxiety at age 3, 11 and 18 years was conducted. Three associative pathways (Rachman, S.J. (1978). Fear and courage. San Francisco: W.H. Freeman) were assessed. Conditioning events were not related to separation anxiety at age 3. Vicarious learning (modelling) in middle childhood (age 9 years) was the conditioning variable most strongly related to separation anxiety at age 11, accounting for 1.8% of the variance in symptoms. Separation experiences (hospitalisations) before the age of 9 were inversely correlated with separation anxiety at age 18. That is, more overnight hospital stays in childhood were related to less separation anxiety in late adolescence. However, none of these conditioning correlates remained significant predictors of separation anxiety in adjusted regression models. In contrast, certain 'planned' separations in early-mid childhood were associated with lower levels of separation anxiety at later ages. Generally, the findings were consistent with predictions from the non-associative theory of fear acquisition. That vicarious learning processes appeared to modulate, albeit to a minor degree, the expression of separation anxiety during mid-late childhood suggests that there may be critical periods during which some individuals are susceptible to the interactive effects of both associative and non-associative processes. These findings serve to illustrate the complexity of fear acquisition, the relevance of developmental factors and the likely interplay between associative and non-associative processes in the etiology of fear and anxiety.

The association between responsibility for a negative outcome, perceived severity of the outcome and perceived likelihood of the outcome was examined in a sample of 70 undergraduate students. Participants were asked to rate the likelihood and severity of 10 negative outcomes, five related to contamination and five related to checking. Thirty-eight participants completed a version of the questionnaire that presented the subject as responsible for the action that may lead to a negative outcome ('personally responsible' group). The remaining 32 completed a version of the questionnaire that presented someone else performing the actions that may lead to a negative outcome ('other responsible' group). Significant differences emerged between the personally responsible and other responsible groups for severity of outcome ratings but not for likelihood of outcome ratings. Specifically, for both washing and checking concerns, participants in the personally responsible group rated the severity of the potential negative outcome as greater than did those in the other responsible group. The results support the claimed general tendency for individuals to regard an outcome as more aversive if they are personally responsible for that outcome, rather than someone else being responsible. The results suggest that, in general, increasing perceptions of personal responsibility will increase cost or severity estimates in subjective danger calculations, and that responsibility may influence OCD phenomena in this way. Finally, the results suggest that attempts to manipulate responsibility in the laboratory may be confounded by necessarily impacting on cost estimates, and therefore on danger expectancies.

The fear dishabituation hypothesis described in the non-associative model of fear acquisition was tested in a longitudinal birth cohort study. Results were consistent with height fear and phobia dishabituation. That is, 're-emergence' of a fear of heights occurred between age 11 and 18 years among individuals who reported higher levels of non-specific stress at age 15. Interestingly, there was no evidence for dental fear dishabituation a finding consistent with the non-associative model of fear acquisition. Strengths and weaknesses of the study were considered and the results discussed in relation to laboratory-based findings on (dis)habituation.

In the current edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV; American Psychiatric Association, (1994) Diagnostic and statistical manual of mental disorders (4th ed.) Washington, DC: author) phobic adults and adolescents are said to 'recognize that the phobia is excessive or unreasonable' given the actual danger posed by the feared situation. The present study examined perceptions of danger in 15 spider phobic subjects and a matched set of controls before, during and after a spider-avoidance test. When detached from the phobic stimulus, phobic subjects: (1) gave higher estimates of the probability of being bitten than controls did; (2) gave higher estimates of the injuries that would result from being bitten and (3) in line with these first two findings, believed their high levels of anticipated anxiety were more reasonable and appropriate to the demands of the situation than controls did. These findings are inconsistent with the prevailing notion that when detached from the phobic situation patients can accurately evaluate the danger of potential phobic encounters. Instead, the findings suggest that phobic individuals, whether detached or in the presence of the feared object, have relatively limited insight into the irrationality of their fears. In examining the mediation of phobic phenomena, both self-efficacy and danger estimates remained significantly related to the anxiety and avoidance experienced in the spider-avoidance task. Further research designed to experimentally establish the likely causal roles of these two constructs is warranted.

Recent investigations of the aetiology and treatment of specific phobias have focussed on clarifying the concerns underlying phobic anxiety. It has been proposed that claustrophobic fear is comprised of separable confinement and suffocation components. This paper presents data from 78 general medical outpatients undergoing magnetic resonance imaging (MRI) scans in two major teaching hospitals. The findings support the two factor structure of claustrophobia, in that exposure to confinement reduced confinement subscale scores, but did not influence suffocation scores.

The Phobic Origins Questionnaire (POQ) [Ost, L.-G. & Hugdahl, K. (1981). Acquisition of phobias and anxiety response patterns in clinical patients. Behaviour Research and Therapy, 19, 439-447.] is the most commonly cited instrument for determining the origins of phobic anxiety and data obtained using this instrument strongly support the role of conditioning in the acquisition of fear reactions. The construct validity of the POQ in assessing episodes of conditioning has been questioned [e.g. Menzies, R. G. & Clarke, J. C. (1994). Retrospective studies of the origins of phobias: a review. Anxiety, Stress and Coping, 7, 305-318.] This paper examined the convergent validity of the POQ by comparing origins' classifications based on the POQ to classifications based on alternative instruments. The convergent validity of the POQ was found to be extremely poor. The POQ was consistently associated with a much greater likelihood of classifying the origin of fear reactions as due to direct conditioning episodes than was found using alternative instruments. The findings question the usefulness of the POQ in examining the origins of phobic anxiety.

Twenty-one OCD sufferers with washing/contamination concerns took part in a controlled treatment trial at the Anxiety Disorders Clinic, University of Sydney. Eleven of the subjects received danger ideation reduction therapy (DIRT) over eight, 1 h weekly group sessions conducted by the second author. Ten subjects were placed on a wait list and did not receive DIRT or any other treatment. DIRT procedures were solely directed at decreasing danger-related expectancies concerning contamination and did not include exposure, response prevention or behavioural experiments. Components of DIRT include attentional focusing, filmed interviews, corrective information, cognitive restructuring, expert testimony, microbiological experiments and a probability of catastrophe assessment task. All subjects were assessed at pre-treatment, post-treatment and three-month follow-up using the Maudsley Obsessional - Compulsive Inventory, Leyton Obsessionality Inventory, Beck Depression Inventory and a Self Rating of Severity Scale. Changes from pre-treatment to after treatment (post-treatment and follow-up scores averaged) were significantly greater in the DIRT condition than in the control condition for all measures. No significant differences were obtained between groups on post-treatment to follow-up change on any measure. The implications of these findings for theoretical models of OCD and its management are discussed.

Theories that fear results from previous traumatic experience (i.e. conditioning theories) have enjoyed widespread support for over half a century. Recent research, however, has cast doubt on the validity of these models in some specific phobias. Two studies on the etiology of height phobia have obtained findings consistent with a non-associative, evolutionary explanation of fear acquisition (Menzies and Clarke, 1993a, Behaviour Research and Therapy, 31, 355-365; Menzies and Clarke, 1995a, Behaviour Research and Therapy, 33, 795-805). Unfortunately, the retrospective nature of these studies limits the conclusions that can be drawn from these data. Like all retrospective research, these studies depend on adult subjects imperfect ability to recall conditioning events that may have occurred many years earlier. The present investigation overcomes these methodological shortcomings by examining the relationship between putative conditioning events before the age of 9 yr and the presence of height fear at ages 11 and 18 yr in a large birth cohort studied longitudinally. To our knowledge this is the first study that has prospectively examined the relationship between relevant traumatic events early in life and the onset of height fear in late adolescence. No positive relationship was found between a history of falls resulting in injury (i.e. fracture, dislocation, intracranial injury or laceration) before the age of 9 and fear of heights at age 11 or 18. Interestingly, falls resulting in injury between the ages of 5 and 9 occurred more frequently in those without a fear of heights at 18 (P < 0.01) - a finding in the opposite direction to that predicted by conditioning theory but consistent with non-associative theories of fear acquisition. In general, the results provide strong support for non-associative models of fear and are difficult to reconcile with conditioning theories.

The relevance of associative learning in the development of Obsessive-Compulsive Disorder (OCD) was investigated in a group of 23 OCD patients whose main concern was washing and 23 age and sex matched control subjects who did not have OCD. OC washers completed an origins instrument based on Menzies and Clarke's (1993, Behaviour Research and Therapy, 31, 355-365) Origins Questionnaire (OQ) for the phobic disorders. Control subjects completed a modified version of this measure designed to give a comprehensive picture of their experiences with relevant contamination-related stimuli. In general, the results question the relevance of associative-learning per se in the development of OC washing. Direct and indirect conditioning events were very rare in the OCD group, accounting for less than 13% of cases. No significant differences between groups were found in the proportion of subjects who knew other OC washers, or had experienced direct associative-learning events prior to onset. Contrary to expectation, significantly more non-OCD subjects had experienced vicarious learning events related to dirt and washing than OCD subjects. However, of note, associative-learning events that took place during episodes of depression were significantly more frequently reported in the OCD group than in the control group. Depression appeared to play a facilitating role in the associative-learning of OC washing. The implications of these findings for theoretical accounts of OCD are discussed.

Three obsessive-compulsive patients received Danger Ideation Reduction Therapy (DIRT) in an initial treatment trial. All three subjects presented with contamination/washing concerns but refused to participate in exposure and response prevention. DIRT is solely directed at decreasing danger-related expectancies concerning contamination. DIRT procedures do not attempt to address inflated personal responsibility. In addition, DIRT does not involve direct or filmed exposure to contamination-related stimuli, or behavioural experiments. Components of DIRT include corrective information cognitive restructuring, filmed interviews, microbiological experiments, attentional focusing and Hoekstra's (1989) probability of catastrophe estimation task. Treatment consisted of between six and ten 1-hr weekly sessions. At post-treatment, substantial reductions in scores on the Padua Inventory, Maudsley Obsessional-Compulsive Inventory and two global rating scales were apparent for all subjects. These improvements were maintained at a 3-month follow-up. The theoretical and clinical implications of these preliminary findings are discussed.

The potential mediating roles of danger expectancies, responsibility, perfectionism, anticipated anxiety and self-efficacy on obsessive-compulsive handwashing were examined. Ratings were obtained from 27 obsessive-compulsive patients before and during a behavioural avoidance test involving a compound stimulus of potting soil, animal hair, food scraps and raw meat. Correlation and partial correlation analyses were conducted to examine the relationships between the cognitive predictor variables and anxiety, urge to wash, time in task and duration of post-test washing. Large and significant relationships between danger expectancies and the dependent measures were obtained, even when alternative mediators were held constant. No other variable remained significantly related to any of the dependent measures when severity of disease ratings were held constant. Results suggest that of the cognitive variables examined, danger expectancies are the most likely mediator of washing-related behaviour in obsessive-compulsive disorder.

The acquisition of acrophobia in a large clinical sample was investigated. 148 patients from a university-based height phobia clinic and 148 age and sex matched non-phobic controls served as Ss. Subjects were assessed with a battery of measures including the Acrophobia Questionnaire [Cohen, D.C. (1977), Behavior Therapy, 18, 17-23], self-rating of severity [Marks, I. M. & Mathews, A. M. (1979) Behaviour Research and Therapy, 17, 263-267] global rating of severity [Michelson, L. (1986), Behaviour Research and Therapy, 24, 263-275], origins questionnaire [Menzies, R. G. & Clarke, J. C. (1993a) Behaviour Research and Therapy, 31, 355-365], and a height avoidance test. Results obtained question the significance of simple associative-learning events in the acquisition of fear of heights. Only 11.5% of fearful Ss were classified as directly conditioned cases. Furthermore, no differences between groups were found in the proportion of Ss who knew other height-fearfuls, had experienced relevant associative-learning events, or the ages at which these events had occurred. Finally, no relationships between mode of acquisition and severity or individual response patterns were obtained. In general, the data were consistent with the non-associative, Darwinian accounts of fear acquisition that continue to attract theorists from a variety of backgrounds [e.g. Bowlby, J. (1975) Attachment and Loss; Clarke, J. C. & Jackson, J. A. (1983) Hypnosis and behavior therapy: the treatment of anxiety and phobia; Marks, I. M. (1987) Fears, phobias and rituals: panic, anxiety and their disorders; Menzies, R. G. & Clarke, J. C. (1993a), (1993b) Behaviour Research and Therapy, 31, 499-501; Menzies, R. G. & Clarke, J. C. (1995)].

Purpose: To respond to Dr. Ingham's letter to the editor, 'Comments on Recent Developments in Stuttering Treatment Maintenance Research Using the Camperdown Program,' which appears in this issue of the Journal of Speech, Language, and Hearing Research. Method: When a treatment program has a performance-contingent maintenance schedule, as the Camperdown Program has, participants vary greatly in the time taken to complete this schedule--up to 2 years or more, in some cases. We reject Dr. Ingham's position that outcomes be measured a year after individual participants conclude their maintenance for the very reasons he has argued many times in the literature. Conclusion: We will continue to measure the outcomes of our clinical trials after a clinically meaningful period and at the same time for all participants. Key Words: Camperdown Program, outcomes, stuttering, We were taken aback by the title of Dr. Ingham's letter, Comments on Recent Developments in Stuttering Treatment Maintenance Research Using the Camperdown Program. We have not done any such [...]

The acquisition of fear of heights in an undergraduate student sample was investigated. Height-fearful (n = 50) and non-fearful (n = 50) groups were formed on the basis of extreme scores to the heights item on the FSS-III (Wolpe & Lang, Behaviour Research and Therapy, 2, 27-30, 1964). Subjects were then assessed with a battery of measures including the Acrophobia Questionnaire (Cohen, Behaviour Therapy, 18, 17-23, 1977), self-rating of severity (Marks & Mathews, Behaviour Research and Therapy, 17, 263-267, 1979), global rating of severity (Michelson, Behaviour Research and Therapy, 24, 263-275, 1986), and a new comprehensive origins questionnaire constructed by the authors. Results obtained question the significance of simple associative-learning events in the acquisition of fear of heights. Only 18% of fearful Ss were classified as directly conditioned cases. Furthermore, no differences between groups were found in the proportion of Ss who knew other height-fearfuls, had experienced relevant associative-learning events, or the ages at which these events had occurred. Finally, no relationships between mode of acquisition and severity or individual response patterns were obtained. In general, the data were consistent with the non-associative, Darwinian accounts of fear acquisition that continue to attract theorists from a variety of backgrounds (e.g. Bowlby, Attachment and loss. London: Penguin, 1975; Clarke & Jackson, Hypnosis and behaviour therapy: The treatment of anxiety and phobias. New York: Springer, 1983; Marks, Fears, phobias and rituals: Panic anxiety and their disorders. New York, Oxford Univ. Press, 1987). Differences with previous studies in which classical conditioning has accounted for the majority of cases are discussed in terms of the methodological differences across studies.

The effectiveness of in vivo exposure and vicarious exposure in reducing children's phobic anxiety and avoidance of water was investigated. Forty-eight water phobic children between the ages of 3 and 8 yr were randomly assigned to one of four groups: (1) in vivo exposure plus vicarious exposure (IVVE); (2) vicarious exposure (VE); (3) in vivo exposure (IVE); and (4) assessment only control. All subjects in the treatment groups received three individually administered treatment sessions. At the conclusion of treatment it was found that the IVE condition had produced statistically and clinically significant gains that had generalized to another situation involving water, and were largely maintained over a period of 3 months. In contrast, the VE condition did not lead to statistically greater treatment benefits than those observed in the control subjects. Furthermore, there was no significant difference between the IVVE condition and the IVE condition in their level of improvement from pre- to post-treatment. Hence, by post-treatment, vicarious exposure had not only failed to produce benefits when used on its own, but had also failed to enhance the benefits achieved through in vivo exposure. However, a tendency for the vicarious component to enhance the maintenance of treatment benefits was found at follow-up. The implications of these findings are discussed.

Background: Information is available about what predicts Lidcombe Program treatment time, but nothing is known about what predicts treatment prognosis. Aims: To investigate the predictors of treatment dropout and treatment outcome for children who were treated for early stuttering with the Lidcombe Program (N = 277). Methods & Procedures: A total of 32 variables were used as predictors in regression analyses of short‐ and medium‐term Lidcombe Program outcome, and of treatment dropout. Outcomes & Results: Regression analyses associated children who have better language skills and easy temperament with better treatment outcome, although only a small portion of the variance of treatment outcome was accounted for by these variables. There was an association between treatment dropout and parental scores on a personality screening tool relating to their impulsivity. Conclusions & Implications: Variables identified as predictors of Lidcombe Program treatment outcome were statistically significant, but not clinically significant. They did not account for a clinically substantive portion of treatment outcomes. Findings about parental impulsivity and their relationship with intervention drop‐out require replication with prospective methods and comprehensive assessment of parent psychological status. This is particularly important because parents are involved in conducting all early interventions. What this paper addsWhat is already known on the subjectInformation is available about what predicts Lidcombe Program treatment time, but nothing is known about what predicts Lidcombe Program treatment outcome.What this paper adds to existing knowledgeThere are predictors of Lidcombe Program treatment outcome that are statistically significant, but none are clinically significant.What are the potential or actual clinical implications of this work?Clinicians can tell parents that nothing has been found that can assist with making prognostic indications about treatment outcome for their children. [ABSTRACT FROM AUTHOR]