Nathaniel McConaghy

Event-related potential indices of semantic processing in schizophrenia.

Event-related potentials (ERPs) were recorded while schizophrenic patients and healthy controls read congruous and incongruous sentences in anticipation of a memory test. The schizophrenic group performed more poorly in both recognition memory and cued recall tests. The two groups did not differ in the amplitude of the N400 component of the ERP but the difference between the ERPs to congruous and incongruous sentences persisted longer in the schizophrenic sample. The schizophrenic sample also showed reduced parietal positivity and a reduced effect of congruity on the late positive component that follows N400. Within the schizophrenic sample, measures of attentional impairment and positive thought disorder were correlated with mean amplitude of both the N400 and the subsequent positivity. The results imply that the structure and spread of activation within semantic memory is not impaired in schizophrenia. Rather, impairments appear to lie in processes required to integrate activated information with the current context.

Paedophilia: a review of the evidence.

Objective: The aim of this study was to critically review the literature concerning the nature and prevalence of paedophilia. Method: The literature of the past 30 years was examined in relation to the authors clinical experience and with emphasis on methodologically appropriate empirical studies. Results: Concern and reporting of child-adult sexual activity has increased markedly in the last decade, although its prevalence has not increased at least since the 1960s. The prevalence in women can be as high as 60%, depending on the definition and method of enquiry used, and female compared to male victims report more negative effects, although a percentage of both men and women report the experience as positive. Validation of effects requires multivariate statistical analysis. Current pro-active procedures to identify paedophiles detect those who victimise boys but do not detect the much greater number of paedophiles who victimise girls. Perpetrators are known to the majority of their female and male victims, and those reported are almost all male; most boys do not consider their prepubertal experiences with older women abusive. Relapse prevention, the current most popular treatment, has been shown to be ineffective for incarcerated child molesters. Conclusions: Child-adult sexual activity should be opposed as an infringement of childrens rights rather than requiring a false belief that it is invariably harmful; whether it should be mandatory for therapists to report it requires examination. Scientifically appropriate evaluation should be an essential component of current treatment programs.

Resistance to treatment of adolescent sex offenders.

Little information is available concerning adolescent sexual offenders and their response to treatment. Of 45 sex offenders treated in two studies, 6 were adolescents and 21 of the 39 adults reported that their deviant behavior had commenced before or during adolescence. All 6 adolescents presented for treatment only following detection of their offenses, which in 3 led to legal charges. Of the 39 adults, 12 sought treatment voluntarily. Subjects were randomly allocated to receive covert sensitization, imaginal desensitization, medroxyprogesterone, or imaginal desensitization plus medroxyprogesterone. The response of the adults was equivalent to the best reported in the literature. Seven of the 39 required additional treatment, 3 being charged for further sexual offenses. Four of the 6 adolescents required additional treatment, 3 being charged with further sexual offenses. These differences were statistically significant. Adolescent sexual offenders may be more resistant to treatment because their sexual urges are under more direct hormonal control whereas in adults sexual urges are in part under the control of behavior completion mechanisms. Sexual offenses in adolescence need to be considered as at least as significant as those of adults, and more intensive follow-up treatment appears indicated in their management.

Methodological issues concerning evaluation of treatment for sexual offenders: Randomization, treatment dropouts, untreated controls, and within-treatment studies.

The value of randomized controlled trials in evaluation of sexual offender treatment has been questioned. Concern was expressed that randomization fails to produce equivalent samples, without apparent appreciation this is inevitable when variables are distributed by chance; lack of equivalence is controlled by use of tests of significance. A further uncriticized and inappropriate procedure in treatment evaluation is separation of the results of subjects who did not complete treatment from those who did, when the outcome of the former group was known. Despite an APA Task Force recommendation, no attention has been given to the consistent finding that no treatment is less effective than placebo psychological therapies. The significance of Type II errors is discussed and the recommendation criticized that within-treatment research be encouraged as an alternative to outcome research. Demonstrating a within-treatment response when that response is associated with a better outcome does not necessarily mean that the treatment was effective. Subjects with a good prognosis could be more able to demonstrate a within-treatment response to the treatment. Nonrandomized matched samples do not adequately control all sample differences. The post hoc statistical reversal of a reported trend for sexual offenders treated with relapse prevention to show a worse outcome than untreated offenders, in order to correct lack of equivalence of the two groups, is considered inappropriate. That relapse prevention was found less effective than no treatment raises the possibility that it has a negative effect. To continue the use of relapse prevention other than in randomly controlled evaluative studies would appear to be unethical.

The effect of decreased catecholamine transmission on ERP indices of selective attention

This study examines the effect of decreased catecholamine transmission on event-related potential (ERP) indices of selective attention. Intravenous clonidine (1.5 μg/kg Catapres), droperidol (15 μg/kg Droleptan), or placebo were administered to healthy adult males prior to performance of a multidimensional auditory selective attention task (SAT) in which dichotically presented sequences of tone pips varied on dimensions of location (left or right ear), pitch (high or low), and duration (short or long). Subjects were required to make a button press response to infrequent “target” stimuli that matched a prespecified stimulus on the three dimensions. ERPs were recorded during the task. Clonidine led to a significant increase of processing negativity (PN) over 200-400 ms at the irrelevant location. Droperidol led to a significant increase in reaction time (RT), a significant decrease in hit rate, and an attenuation of PN over the 200- to 400-ms and 400- to 700-ms epochs. Neither substance led to a significant change in P3 amplitude. The role of catecholamines in the selective attention subprocesses of “tuning” and “switching” is discussed.

Aversive and positive conditioning treatments of homosexuality

Abstract Thirty-one male homosexual patients were randomly allocated to receive either aversive therapy, in which unpleasant shocks were associated with pictures of nude males; or positive conditioning, in which pictures of nude women were associated with similar pictures of men and later with pictures of heterosexual relationships. The patients were further randomly allocated to receive either procedure according to a forward or backward conditioning paradigm. Before, 3 weeks and 1 yr following 5 days of treatment, the patients were shown a film containing at 1-min intervals 10-sec segments of pictures of nude women or men. During this and all treatment procedures their penile volume responses were measured. The positive conditioning technique proved ineffective and hence acted as a placebo treatment control for the aversive therapy. Patients reported significantly greater reduction in homosexual feelings and behaviour following the latter. After both the aversive and the positive conditioning technique, patients showed significantly less penile volume increase to the pictures of men. There was no trend for this change to be greater following aversive therapy. It was concluded that this therapy reduced the secondary reinforcement value of homosexual stimuli but did not alter sexual orientation.

Allusive thinking in parents of schizophrenics. Meta-analysis

Romney (J. Nerv. Ment. Dis. 178:481-486, 1990) performed a meta-analysis of studies examining psychometrically assessed “thought disorder” in the relatives of schizophrenics. He concluded that thought disorder was more prevalent in the relatives of schizophrenics than control subjects. The present review focuses on only those studies that measured “allusive thinking” using the Lovibond-Rapaport Object Sorting Test in parents of schizophrenics. Even when the meta-analysis included this more limited number of studies, it demonstrated that the parents of schizophrenics were 2.42 times more likely to obtain high scores on the Object Sorting Test, confirming replication of the original McConaghy (J. Neurol. Neurosurg. Psychiatry 22:243-246, 1959) finding. This effect remained significant when the original study was excluded from the meta-analysis. The predictive strength of parental Object Sorting Test score as a familial risk factor for the development of schizophrenia is discussed.

Schizotypy: phenotypic marker as risk factor.

OBJECTIVE To evaluate measures of schizotypy as familial risk factors for schizophrenia with the aim of making recommendations for assessing schizotypy as part of screening procedures for identifying people at risk of schizophrenia. METHOD Published studies using self-report and interview-based measures of schizotypy to assess relatives of patients with schizophrenia are reviewed. A parent study is reported evaluating the diagnostic accuracy of parental schizotypy as assessed by three questionnaire-based measures: the Chapman Perceptual Aberration and Physical Anhedonia Scales, and the Eysenck Psychoticism Scale. Group scores for these self-report ratings of 23 parent-pairs of patients with schizophrenia, 20 parent-pairs of patients with chronic nonpsychotic psychiatric disorder, and 19 parent-pairs of healthy comparison subjects are compared. RESULTS Consistent with published evidence that self-report measures of psychosis-proneness and schizotypy do not consistently reflect familial risk factors that are specific for schizophrenia, scores on questionnaire measures of schizotypy did not distinguish the parents of patients with schizophrenia from the parents in the other two groups. CONCLUSIONS Interview-based assessments of schizotypy better assess familial risk factors than self-report measures of schizotypy. Questionnaire measures of schizotypy should be supplemented by interview-based assessments when screening for individuals at risk of schizophrenia.

Imaginal Desensitization: A cost-effective treatment in two shop-lifters and a binge-eater resistant to previous therapy

Case reports are given of three patients, two suffering from compulsive shop-lifting and one from binge-eating, who responded to a weeks treatment with imaginal desensitization after having failed to respond to prolonged interpretative psychotherapy. Expectancy of improvement did not appear to play a major role in their response, but it appears impossible to disprove that expectancy determines the response to this or any form of psychotherapy. Whether or not imaginal desensitization acted specifically in the present study, in view of its cost-efficacy it is suggested it is worthy of trial in impulse disorders which have persisted despite treatment.

P300 Indexes Thought-Disorder in Schizophrenics, But Allusive Thinking in Normal Subjects

Loosening of thinking as assessed by the Object Sorting Test (OST) has been found in a percentage of normal subjects but in a higher percentage of schizophrenics, and is familially transmitted in both groups. Loosening of thinking in normal subjects is not associated with evidence of impaired function or increased psychopathology, and in recognition of this, it was termed allusive thinking rather than thought disorder. Both OST-assessed loosening and concreteness of thinking were found to be present independently in a high percentage of schizophrenics, so that both were considered to contribute to schizophrenic thought disorder. The presence of OST-assessed loosening in schizophrenics would, therefore, be predicted to correlate partially rather than totally with measures of schizophrenic thought disorder. It has been suggested that OST-assessed loosening in normal subjects is due to a genetically determined reduction in strength of an inhibitory process that limits the spread of activation of semantic associations and results in a predisposition to schizophrenia. The brain eventrelated potential P300, which is, in part, under genetic control, may index this inhibitory process. Therefore, it was predicted that in normal subjects, P300 would correlate with OSTassessed loosening of associations. If schizophrenic thought disorder is due to a further weakening of this inhibitory process, it can be predicted that P300 in schizophrenics correlates only weakly with OST-assessed loosening of thinking, but more strongly with schizophrenic thought disorder. In a study in which P300 was elicited using a difficult selective attention task with 15 unmedicated schizophrenics and 22 healthy subjects, all three predictions were supported.