By Y. Folleck. California College of the Arts.
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Effects of Chapter 102: Pathophysiology and Treatment of Cocaine Dependence 1473 lamotrigine on behavioral and cardiovascular responses to co- agents: newmedications for cocaine dependence. Am J Drug Alcohol Abuse 2000;26(1): Depend 1997;48:149–151. The effects of Institute on Drug Abuse collaborative cocaine treatment study: memantine on the subjective, reinforcing and cardiovascular rationale and methods. Arch Gen Psychiatry 1997;54(8): effects of cocaine in humans. Gamma-vinyl gamma-aminobu- cognitive, supportive-expressive, and drug counseling therapies tyric acid attenuates the synergistic elevations of nucleus accum- for cocaine dependence. J Consult Clin Psychol 1998;66(3): bens dopamine produced by a cocaine/heroin (speedball) chal- 484–492. Vigabatrin, a treatments for cocaine dependence: National Institute on Drug gabaergic antiepileptic drug, causes concentric visual field de- Abuse collaborative cocaine treatment study. Maude-Griffin PM, Hohenstein JM, Humfleet GL, et al. 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Arch Gen Psychiatry bral metabolism in polydrug abusers during early withdrawal: 1996;53:409–415. Decreased digital beneficial effects of reinforcement of cocaine abstinence in flowpersists after the abatement of cocaine-induced hemody- methadone patients. Isradipine prevents global they will come: contingency management for treatment of alco- and regional cocaine-induced changes in brain blood flow: a hol dependence. A comprehensive guide to the application of contin- preliminary study. Reinforcing operants agents: SPM analyses of early abstinence. Yale University School other than abstinence in drug abuse treatment: an effective alter- of Medicine and VA-Connecticut Healthcare System. J Consult Clin Psychol 1997;65: Prob Drug Depend 2000;60(Suppl. Schedule of metabolic activity during different stages of cocaine withdrawal. Development of a therapeutic vaccine for the treatment 104. All these advances cellular neurobiology, as well as pathophysiology, of opiate have and will continue to make further revelations concern- addiction. Clearly, the greatest advances have come about ing each of the addictions, and in particular, for this discus- ultimately because of the first successful cloning of a specific sion, opiate addiction. The reports of the groups of Evans and colleagues PRECLINICAL STUDIES OF CHRONIC from Los Angeles and Kieffer and colleagues from Stras- ADMINISTRATION AND WITHDRAWAL bourg, France, followed by the cloning of - and -opioid EFFECTS OF OPIATES IN DIVERSE AND receptors of rodents and in humans by Yu, Uhl, and others, NOVEL ANIMAL MODELS opened new doors for both animal and basic clinical research studies, as well as human molecular genetics studies (1–5). Neuropeptide and Neurotransmitter Other notable technologic advances have been made re- Systems Primarily Affected cently and are continuing to be made. Possibly the most Opioid Peptides and Receptors: Molecular, Cell dramatic of these, from which we will undoubtedly see novel Biological, and Signal Transduction Alterations, and unexpected findings over the next few years, is the de- and Possible Implications for Pathophysiology of velopment of microarray technology, to determine the Opiate Addiction changes in levels of gene expression of literally thousands of genes simultaneously (although not yet with the sensitivity After the definitive discovery of specific opioid receptors in required to detect changes in mRNA levels reflecting gene 1973, research began to address what had been a long-stand- expression of many neuropeptides and most neurorecep- ing hypothesis, later apparently to be disproved. The hy- tors), and also even newer microarray technology for identi- pothesis was that tolerance to opioids depended on down- fication and screening for human polymorphisms, including regulation or decreased availability of, and thus access to, single nucleotide polymorphisms (SNPs) (6,7). By using -opioid receptors after chronic -opioid agonist (e. Later, this could be considered on earlier and current best techniques, profound advances to result from 'desensitization' of -opioid receptors while have been made in each of three areas, of which only a few still on the cell surface (i. Moreover, a significant decrease in production of and this finding altered their initial hypothesis, that such new receptors could contribute to a so-called down-regula- chronic exposure to an opioid agonist would cause down- tion. Although the terms down-regulation and up-regulation regulation of receptors (55–57). Subsequent studies using have been used loosely with inadequate definitions, the diverse ligands and dosing regimens continued to give varied overall concept that chronic -opioid agonist administra- results, with up-regulation of -opioid receptors, down- tion may cause reduced capacity to bind, or increased capac- regulation of -opioid receptors, and no change of -opi- ity to bind, or to have no effect, but each alternative with oid-receptor density or binding after chronic -opioid-ago- reduced capacity of activated receptors to have an effect nist administration all reported. The prevailing concept for (or 'tolerance'), has persisted, and repeatedly studied, with receptor-agonist ligands and, in this case, specifically ago- conflicting results. The earliest studies to address this issue nists for the -opioid-receptor system, has been that persis- of impact of chronic opioid administration effects on bind- tent activation of receptors would generally lead to down- ing were conducted to elucidate the well-documented and regulation, and conversely, the persistent deprivation of re- accepted phenomenon of tolerance, both in cell systems and ceptors of specific ligands would generally lead to persistent in whole animals. Morphine was the most common opiate lack of activation of receptors and thus to up-regulation. From 1996 to 2000, several intriguing articles appeared Later, the effects of specific opioid antagonists on opioid- concerning the effects of opioid-agonist administration on receptor binding or density were also conducted, primarily receptor internalization (44–52). The binding of opioid antagonists, of relevant studies on signal transduction, primarily through course, does not involve coupling; that is, no Gi/o-pro- G-protein–coupling mechanisms, but also alternative tein–coupled signal transduction mechanisms are involved, mechanisms, appeared and extended our earlier knowledge because the opioid antagonists (according to most current and may ultimately explain some of the apparently conflict- theories) do not activate receptors, but rather prevent activa- ing results concerning receptor binding and density (12–15, tion by endogenous or exogenous opioids. There is now animals was shown to alter, at a cellular level, the function essentially a consensus from many and diverse studies that of neurons, specifically in the locus ceruleus, and also to the chronic administration of opioid antagonists, primarily lead to tolerance and physical dependence (12,18,20,24). There has, how- inhibition by morphine of adenylyl cyclase, as well as result- ever, been some controversy regarding whether opioid an- ant inhibition of the cyclic adenosine monophosphate tagonist treatment and the resultant up-regulation of - (cAMP)–dependent cascade, followed by, during chronic opioid receptors leads to a sensitized state, that is, a state morphine treatment, a compensatory increase of activity of in which an opioid agonist would have a greater than usual adenylyl cyclase, with an increase in the cAMP-dependent effect on any system. This has been addressed both in animal cascade, including increases in protein kinase A and in- models and in humans, with some conflicting results. Nestler and Aghajanian hypothesized that this up- merous studies have used several different opioid agonists, regulation of the entire cAMP pathway in the locus ceruleus primarily morphine, given by different regimens, ranging represents a compensatory change to oppose or offset the from intermittent injections to repeated pellet implantation, initial inhibitory effects of morphine and thus could be con- to a few studies using chronic administration by pump, sidered to be one component of tolerance (18,20). They there have been conflicting study results and no consensus also suggested that these increases in the cAMP pathway on the effects on -opioid-receptor binding or density. The components could contribute to opiate dependence and results reported from studies conducted in living adult ani- thus withdrawal, because these changes could be involved mals, for the most part, have shown no overall net changes in a variety of functions once no longer opposed by mor- in -opioid-receptor–binding capacity, that is, no overall phine (18,20). This concept is of particular relevance be- changes in opioid-receptor density, as measured by quanti- cause this up-regulation of the entire cAMP pathway during tative autoradiography or by classic homogenate binding chronic morphine exposure has been shown to occur pre- assay studies, and, more recently, no overall changes in - dictably in the locus ceruleus of all strains and species of opioid-receptor mRNA levels. Because the locus ceruleus is the ducted in living adult animals by the groups that included major noradrenergic nucleus of the brain, diverse noradren- those who first defined opioid receptors, showed no altera- ergic functions that are known to be activated in opiate Chapter 104: Neurobiology and Pathophysiology of Opiate Addiction 1493 withdrawal could be affected. Nestler and other groups tein–coupled family of seven transmembrane receptors; showed that although these changes occur uniformly in the there has been further documentation of receptor phosphor- locus ceruleus neurons, and in a few other brain regions, ylation, desensitization, and uncoupling from G proteins, particularly in the nucleus accumbens, this type of change as well as new studies documenting internalization (endocy- in the nucleus accumbens is strain dependent, and also such tosis) of opioid receptors (36–52).
Lack of evidence of sexual trans-Lack of evidence of sexual trans- 2003;139:994–1000 cheap diflucan line. Scabies: molecular per- prospective follow-up study discount diflucan 150mg amex. Deaths associated with ivermectin treatment of women discount diflucan online mastercard. Crusted scabies: clinical and prevalence of hepatitis C virus infection among sexually active non- immunological fndings in seventy-eight patients and a review of the intravenous drug-using adults buy diflucan 200mg low price, San Francisco, 1997–2000. Hepatitis C virus among factors associated with follow-up care. Am J Obstet Gynecol self declared non-injecting sexual partners of injecting drug users. Unsafe sex and increased sexual HIV transmission: quantifying the per-act risk for HIV on the incidence of hepatitis C virus infection among HIV-infected men basis of choice of partner, sex act, and condom use. Sex Transm Dis who have sex with men: the Swiss HIV Cohort Study. Increase in HCV inci- HIV seroconversion in health care workers after percutaneous exposure. HIV postexposure prophylaxis hepatitis C infections in HIV positive homosexual men: is sexual trans- use among Ontario female adolescent sexual assault victims: a prospec- mission feeding the increase? Postexposure prophylaxis C virus in HIV-positive men who have sex with men linked to high-risk for HIV in children and adolescents after sexual assault: a prospec- sexual behaviours. Evidence of a large, international HIV post-exposure prophylaxis for sexual assault survivors. With peak onset at 18-25 years, schizophrenia causes loss of productivity and high medical and social services costs. The suffering of patients with schizophrenia and their families is usually great. Some fortunate individuals manage relatively uninterrupted lives. However, sustained recovery maintained 5 years after the initial episode is only 14% (Robinson et al, 2004). It is likely this name will change in the life of the reader. Schizophrenia is diagnosed (at the moment) by the presence of hallucinations, delusions and formal thought disorder. This is like diagnosing heart disease only at the time of myocardial infarction. Recently, schizophrenia has been conceptualized in four phases. By the time hallucinations and delusions appear, brain changes have occurred; early detection and prevention has become an area of research interest (Insel, 2010). In 1893, Emile Kraepelin (German) drew a distinction between “manic depressive insanity” (bipolar disorder) and “dementia praecox” (meaning dementia of the young; now called schizophrenia). Bleuler believed that formal thought disorder (FTD) in which the patient slips off one track of thought onto another is the primary/defining feature of schizophrenia, rather than the more obvious positive symptoms of hallucinations and delusions. An early categorization divided the symptoms into two groups: “positive” and “negative” (Andreasen et al, 1982). The positive symptoms (phenomena which are in addition to normal experience), are the remarkable features of the acute/psychotic phase, that is, hallucinations, delusions and FTD. The negative symptoms (Andreasen et al, 1982; loss of personality features and abilities) are the most troublesome symptoms of the chronic phase of schizophrenia. The DSM-5 sub-classification is as follows: 1) Affect impairment (flattening or blunting) - diminished emotional expression, with reduced expression of emotion in the face, speech and bodily movements, 2) Anhedonia - reduced ability to experience pleasure, reduced interpersonal skills, 3) Asociality – apparent lack of interest in social interaction, 4) Avolition (apathy) - reduced self-initiated purposeful activities, 5) Alogia – diminished speech output (this is another view of poverty of speech, discussed in Chapter 6). While the negative symptoms are regarded as the predominant feature of the chronic phase, they may be detected as early as the first psychotic episode. Some researchers found that certain symptoms did not easily fit into the two category model, and developed a three category/factor model (Bilder et al, 1985). Along with the positive and negative symptom groups, a third group was designated “disorganisation” - this included some thought disorder, bizarre behaviour, impaired attention and some cognitive dysfunction. A range of other ways of grouping the symptoms of schizophrenia have been suggested, but will not be described. Medical students only require knowledge of the positive/negative symptom division; those wanting to do exceptionally well in psychiatry should be aware the third set of disorganized symptoms/cognitive dysfunction. Symptoms (Psychotic/acute) Hallucinations See Chapter 5. These items were kept by a young man with schizophrenia. He was socially isolated and secretive and brought to hospital by his parents. His parents explained that he had written “Cursing Jar For Good” on the lid of this jar, and had written multiple “curses” concerning “enemies” which he placed inside. His parents told that he behaved as if these curses were a serious matter, and he expected them to be effective. While not proof, this activity was highly suggestive of psychosis. The idea of a “cursing jar” appeared to have come from the fashion of maintaining a “cussing jar” in work-places and pubs, into which people were obligated to place money if they “cussed” (cursed/swore) – at intervals the contents to be donated to charity or similar “good” cause. The evidence suggested the patient believed he could cast spells or curses on other people (delusion). This was not appropriate in his culture and suggested a delusion. A well groomed young man (clothes in the background) was brought to hospital. When staff unpacked his belongings, they found a bag of human faeces. When he recovered, the patient explained he had believed his faeces contained gold dust, which he had intended to extract. The delusions described above are spectacular – the majority are far less so. Form of thought – Formal Thought Disorder (FTD) See Chapter 6. As mentioned above, derailment, incoherence and neologisms are ranked with the positive symptoms, while poverty of thought is ranked with the negative symptoms. Symptoms (Negative/chronic) The symptoms mentioned in DSM-5 will be discussed first. Accordingly, the mood disorders of current times [depression/mania] are still sometimes referred to as “affective” disorders, but this is not recommended. In examination of the mental state, the term affect refers to “the external manifestation of the internal feeling state”. It is said that affect is to mood as weather is to climate, introducing the notion of immediacy and brevity. In our interactions with others we expect some “emotional contact”, interest or personal warmth. We expect some animation, some facial, hand and body movements, some variation in tone of vice and speed of speech, or some sign of vigour or energy, during discussion of different topics. People with schizophrenia may have “blunted”, “flat” or “restricted” affect. Such patients tend to have relatively immobile face, limbs and trunk, with little change in speed of speaking or pitch of voice, irrespective of the topic of conversation. There appears to be reduced interest and personal warmth. It is assumed from these external manifestations that the internal feeling do not vary in the usual manner. This is a fair assumption, particularly in view of the fact that many people with flat affect also complain of lacking the ability to feel emotions. This occurs when an individual is thinking/talking on a subject, but displaying inappropriate feelings. For example, a patient talking of the death of a much loved relative may laugh uncontrollably. Anhedonia Anhedonia is the inability to experience pleasure. It is observed in various types of depressive disorder and schizophrenia.
Autoimmune encephalomyeli- long-term stability of new hippocampal place cell maps by tis ameliorated by AMPA antagonists purchase diflucan 150mg otc. Normal aging: regionally specific changed in hippo- tive symptoms in schizophrenia by glycine cheap diflucan on line. Multistability of cognitive placebo-controlled purchase diflucan 200mg online, crossover trial of glycine adjuvant therapy maps in the hippocampus of old rats diflucan 200mg with visa. Efficacy of high- amino acid receptors in two mouse strains. Neurobiol Aging dose glycine in the treatment of enduring negative symptoms 1993;14:197–206. Declines in mRNA expression of different sub- 90 Neuropsychopharmacology: The Fifth Generation of Progress units may account for differential effects of aging on agonist 252. Circuit-specific and antagonist binding to the NMDA receptor. J Neurosci 2000; alterations in hippocampal synaptophysin immunoreactivity 20:1666–1674. Hippocampal depen- of aged long-evans rats: relationship to spatial learning. Neurosci- dent learning ability correlates with N-Methyl-D-Aspartate ence 1996;74:741–756. Proc Natl Acad Sci USA 1996; receptors and apoptotic neurodegeneration in the developing 3121–3125. GRIGORIADIS HISTORICAL PERSPECTIVES CHARACTERISTICS OF THE CRF PEPTIDE AND GENE SEQUENCES In 1948 Sir Geoffrey Harris first proposed the concept that Amino Acid Sequence and Structure of the hypothalamus plays a primary role in the regulation of CRF the pituitary-adrenocortical axis. Subsequently,during the 1950s,Guillemin and Rosenberg,and Saffran and Schally The sequence of CRF has been determined in a variety of independently observed the presence of a factor in hypo- species including sheep,humans,rats,pigs,goats,and cows. Rat and human CRFs are identical tropic hormone (ACTH,corticotropin) from anterior pi- to one another and differ from ovine CRF by seven amino tuitary cells in vitro. All three CRFs have close amino acid homol- lamic hypophysiotropic factor to be recognized,its ogy and share some biological properties with sauvagine,a chemical identity remained elusive until 1981,when Wylie 40-amino acid peptide that exists in frog skin,and urotensin Vale and colleagues at the Salk Institute reported the I,a 41-amino acid peptide derived from fish urophysis. Just over a decade later,Vale and col- bles rat and human CRF. This initial discovery led to the identification of a ity of the peptide. Studies to determine the solution struc- second receptor subtype (termed CRF2),which has now ture of CRF using proton nuclear magnetic resonance sug- been localized and characterized in a variety of species gest that human CRF comprises an extended N-terminal (see the following). An -helical oCRF(9-41) has been and its related receptor targets. More detailed and compre- demonstrated to be an antagonist of CRF (8),which under- hensive information on CRF is available in recent reviews scores the necessity of the -helical conformation for recep- (3,4) and books (5,6) on the topic. Detailed descriptions of the organization of CRF immunoreactive cells and fibers in rat brain have been published (11–13). Morphologic data clearly indicate that the paraventricu- lar nucleus of the hypothalamus (PVN) is the major site of CRF-containing cell bodies that influence anterior pituitary hormone secretion. These neurons originate in the parvocel- lular portion of the PVN and send axon terminals to the capillaries of the median eminence. CRF is also present in a small group of PVN neurons that project to the lower brainstem and spinal cord; this group of neurons may be FIGURE 7. Amino acidsequences of ovine andrat/human corti- cotropin-releasing factor (CRF) and related peptides including involved in regulating autonomic nervous system function. Rat CRF and human CRF are identical Other hypothalamic nuclei that contain CRF cell bodies and differ from ovine CRF by seven amino acid residues, which include the medial preoptic area,dorsomedial nucleus,arcu- are denoted by the shading. All peptides are amidated at the carboxyterminus; theamidationis essentialfor biologicalactivity. The neocortex contains primarily CRF interneurons with bipolar,vertically oriented cell bodies predominantly localized to the second and third layers of the cortex and genes have been determined (9,10). The locus of the CRF projections to layers I and IV. In addition,scattered cells gene is on chromosome 8q13 in the human. The CRF genes are present in the deeper layers that appear to be pyramidal are quite similar to one another,containing two exons sepa- cells. Although CRF-containing neurons are found rated by intervening intron 686 to 800 base pairs long. The throughout the neocortex,they are found in higher densities first exon encodes most of the 5′-untranslated region of in the prefrontal,insular,and cingulate areas. CRF neurons the mRNA and the second encodes the entire prepro-CRF in the cerebral cortex appear to be important in several precursor polypeptide,which is 187 to 196 amino acids behavioral actions of the peptide,including effects on cogni- long; the carboxy end of the precursor contains the 41- tive processing; furthermore,dysfunction of these neurons amino acid peptide sequence. The high incidence of homol- may contribute to many CNS disorders (see the following). CRF neu- flanking DNA sequences are most likely to contain the rons in the central nucleus of the amygdala project to the DNA sequence elements responsible for glucocorticoid, parvocellular regions of the PVN,the parabrachial nucleus cAMP and phorbol ester regulation,tissue-specific expres- of the brainstem,and thus may influence both neuroendo- sion,and enhancer activity. Although a consensus cAMP crine and autonomic function in addition to behavioral ac- response element has been identified,located 200 base pairs tivity. CRF neurons originating in the bed nucleus of the upstream from the major transcription initiation site,no stria terminalis send terminals to brainstem areas such as obvious glucocorticoid response elements or activation pro- the parabrachial nuclei and dorsal vagal complex,which tein (AP) 1-binding elements are present. CRF fibers also interconnect 2 binding site,which may mediate the responses to protein the amygdala with the bed nucleus of the stria terminalis kinase A and C,is present 150 base pairs upstream from and hypothalamus. Scattered CRF cells with a few fibers the major start site. Distribution of CRF in the CNS Several groups of CRF cell bodies are present throughout The distribution and localization of CRF mRNA in the the brainstem. In the midbrain,CRF perikarya are present central nervous system (CNS) have been evaluated using in the periaqueductal gray,Edinger-Westphal nucleus,dor- Northern blot analysis and in situ hybridization histochem- sal raphe nucleus,and ventral tegmental nucleus. Radioimmunoassay and immunohisto- tions from the dorsal-lateral tegmental nucleus to a variety chemical studies have been critical in the determination of of anterior brain areas such as the medial frontal cortex, the neuroanatomic organization of CRF immunoreactive septum,and thalamus have also been described. Overall,there is good concor- CRF cell bodies are localized in the locus ceruleus,para- dance between studies demonstrating a widespread distribu- brachial nucleus,medial vestibular nucleus,paragigantocel- Chapter 7: Corticotropin-Releasing Factor 93 lular nucleus,and periaqueductal gray. CRF neurons origi- closer to the structure of CRF in those species (17,18) led nating in the parabrachial nucleus project to the medial to the suggestion that other forms of CRF may exist in preoptic nucleus of the hypothalamus. Furthermore,with the cloning of the CRF2 re- large groups of cell bodies are present in the nucleus of ceptor subtype,it became apparent that because sauvagine the solitary tract and dorsal vagal complex with ascending and urotensin had even higher affinity and activity at this projections to the parabrachial nucleus. Scattered groups subtype than CRF itself (19),a mammalian form of these of cell bodies are also present in the medullary reticular peptides may exist that would serve as the endogenous li- formation,spinal trigeminal nucleus,external cuneate nu- gand for the CRF2 subtype. Indeed,a mammalian form of cleus,and inferior olive. Within the spinal cord,CRF cell bodies are present in laminae V to VII and X and in the intermediolateral column Amino Acid Sequence and Structure of of the thoracic and lumbar cord. CRF fibers originating in Urocortin the spinal cord form an ascending system terminating in The sequence of urocortin has been determined in both rats the reticular formation,vestibular complex,central gray, and humans. In rat,urocortin was identified using a library and thalamus. This ascending CRF system may play an derived from rat midbrain and a carp urotensin cDNA important role in modulating sensory input. A full-length cDNA was described and encoded a spinal cord CRF neurons may represent preganglionic neu- putative 40-amino acid peptide that was related to CRF rons that modulate sympathetic outflow. The human form was subsequently identified using a cDNA probe encoding the peptide region of rat urocortin Distribution of CRF in Peripheral Tissues and screening a human genomic library (21). The resulting putative peptide demonstrated 88% identity to rat at the In addition to its CNS distribution,CRF has been localized nucleotide level and 95% identity at the amino acid level in a variety of peripheral tissues (14). In both species,urocortin is a 40-amino acid active fibers are present in the intermediate lobe of the pitui- residue single-chain polypeptide; the two forms differ by tary; these fibers originate in the hypothalamus. A physio- only two amino acids at positions 2 (Asn to Asp) and 4 logic role has been proposed for CRF in regulating pro- (Ser to Pro) (21). In addition to the homology between the opiomelanocortin (POMC)-derived peptide secretion from species,the deduced amino acid sequence of rat and human the intermediate pituitary. CRF has also been localized in urocortin exhibits sequence identity with urotensin I (63%) the adrenal medulla of a variety of species and is increased and human CRF (45%) (20).
Additionally buy diflucan 200 mg low cost, the regression weights for items 15–17 increased to 0 purchase 200mg diflucan free shipping. After a satisfactory model fit has been obtained for the baseline data set B purchase discount diflucan on-line, the exact same model was fitted to the 12-month data set B (see Table 54) buy diflucan american express, showing that this solution was also adequate for that data set. TABLE 53 Goodness-of-fit indices for the confidence and motivation subscale Baseline data set B 12-month data set B No error variance Error variance Error variance Fit index correlation correlation correlations Satorra–Bentler scaled χ2/df 9. Fit indices for the replication of the final model with the 12-month data set B are also shown. This issue may be freely reproduced for the purposes of private research and study and extracts (or indeed, the full report) may be included in professional journals 199 provided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising. Applications for commercial reproduction should be addressed to: NIHR Journals Library, National Institute for Health Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK. APPENDIX 18 TABLE 54 Goodness-of-fit indices for the peer norms subscale Baseline data set B 12-month data set B No error variance Error variance Error variance Fit index correlation correlation correlation Satorra–Bentler scaled χ2/df 10. Fit indices for the replication of the final model with the 12 months Dataset B are also shown. Family approval/behaviours and child attitudes (items 23–32 without item 31) The fit indices of the first model (without any error variance correlations) showed that the solution was marginally adequate, although the RMSEA was slightly elevated, at 0. After correlating error terms for pairs of items with shared meaning, the fit became excellent (Table 55). After a satisfactory model fit had been obtained for baseline data set B, the exact same model was fitted to the 12-month data set B (see Table 55), showing that this solution was also excellent for that data set. Behaviours and strategies (items 33–50) The fit indices of the first model (without any error variance correlations) showed that the solution was marginally adequate, although the RMSEA was slightly elevated, at 0. After correlating error terms for pairs of items with shared meaning, the fit has become very good (Table 56). After a satisfactory model fit had been obtained for baseline data set B, the exact same model was fitted to the 12-month data set B (see Table 56). The fit for the replication data set was worse, and the RMSEA was now > 0. A multigroup invariance test (reported below) will provide more detailed information about the adequacy of this model for the 12-month data set. TABLE 55 Goodness-of-fit indices for the family approval/behaviours and child attitudes subscale Baseline data set B 12-month data set B No error variance Error variance Error variance Fit index correlation correlation correlation Satorra–Bentler scaled χ2/df 6. Fit indices for the replication of the final model with the 12-month data set B are also shown. Fit indices for the replication of the final model with the 12-month data set B are also shown. Results of multigroup invariance test The following analyses were conducted to test specifically the suitability of the factor solution obtained from baseline data set B with the 12-month data set B. These tests were conducted separately for each subscale. A baseline model (model 1) for each subscale tested for generalisability of the final factor solutions reported to the 12-month data set (configural invariance). In this model, the 12-month data set received separate factor loadings and error variances. In the next model (model 2), the factor loadings of the 12-month data set were fixed to the values estimated for the baseline data set. Comparing the fit between models 1 and 2 is thus a test of metric invariance. In other words, if model 2 does not provide a significantly improved fit (as assessed by a chi-squared difference test) compared with model 1, the factor loadings for the two data sets can be assumed to be equal. In the next step, invariance of error variation and the error term correlations was investigated. Model 3 fixed the general error variance and the values of error term correlations of the 12-month data set to the values for the baseline data set. Again, if there is no significant improvement compared with the preceding model (in this case model 2), residual invariance can be concluded. Results of invariance tests Confidence and motivation (items 6–14) The metric invariance test for the confidence and motivation subscale failed to demonstrate full metric invariance as the comparison of model 2 with model 1 was significant (Table 57). An inspection of the results of the CFA with the two data sets separately revealed a clear difference in the factor loading for item 10. For the baseline data set B, the factor loading of item 10 was 0. As a result, partial invariance was testing whereby only the factor loading of item 10 was allowed to vary between samples (model 2a). The fit of model 2a was not a significant improvement on model 1, confirming partial metric invariance. Last, residual invariance was confirmed through model 3. TABLE 57 Summary of the results from the measurement invariance test of the confidence and motivation subscale Model χ2 (df) Model comparison Δχ2 (Δdf) p-value 1 (configural invariance) 132. This issue may be freely reproduced for the purposes of private research and study and extracts (or indeed, the full report) may be included in professional journals 201 provided that suitable acknowledgement is made and the reproduction is not associated with any form of advertising. Applications for commercial reproduction should be addressed to: NIHR Journals Library, National Institute for Health Research, Evaluation, Trials and Studies Coordinating Centre, Alpha House, University of Southampton Science Park, Southampton SO16 7NS, UK. APPENDIX 18 Peer norms (items 15–22) The metric invariance test for the peer norms subscale also failed to demonstrate full metric invariance as model 2 provided a significant improvement on model 1 (Table 58). An inspection of the results of the CFA with the two data sets separately revealed a clear difference in the factor loading for item 15. For the baseline data set B, the factor loading of item 15 was 0. As a result, partial invariance was testing whereby only the factor loading of item 15 was allowed to vary between samples (model 2a). The fit of model 2a did not provide a significant improvement on model 1, thereby confirming partial metric invariance. Last, residual invariance was confirmed through model 3. As in the above CFA conducted separately for the two data sets, the regression weight for item 15 was also low here, suggesting that it may be advisable to consider removing this item from the scale. Family approval/behaviours and child attitudes (items 23–32 without item 31) As with confidence and motivation and peer norms, the metric invariance test for the family approval/ behaviours and child attitudes subscale failed to demonstrate full metric invariance. As shown in Table 59, model 2 provided a significant improvement on model 1. An inspection of the results of the CFA with the two data sets separately revealed a clear difference in the factor loading for item 24. For the baseline data set B, the factor loading of Item 24 was 0. As a result, partial invariance was testing whereby only the factor loading of item 24 was allowed to vary between samples (model 2a). The fit of model 2a was not a significant improvement on model 1, confirming partial metric invariance. Last, residual invariance was confirmed through model 3. Behaviours and strategies (items 33–50) As with the other subscales, full metric invariance could not be established for the behaviours and strategies subscale (Table 60). An inspection of the results of the CFA with the two data sets separately revealed no very large difference in factor loadings, and for that reason inspection of modification indices guided the selection of factor loadings that were going to be allowed to be vary in a subsequent partial invariance test (model 2a). However, even when eight factor loadings were allowed to vary freely in the second sample, the fit of model 2a was significantly different from that of model 1. TABLE 58 Summary of the results from the measurement invariance test of the peer norms subscale Model χ2 (df) Model comparison Δχ2 (Δdf) p-value 1 (configural invariance) 101. TABLE 59 Summary of the results from the measurement invariance test of the family approval/behaviours and child attitudes subscale Model χ2 (df) Model comparison Δχ2 (Δdf) p-value 1 (configural invariance) 100. The development phases were an important starting point but had limited resources, and therefore much of psychometric evaluation took place with the main trial data set. Although it would have been better to have an established questionnaire before commencing the trial, the process that has been undertaken still exceeds the evaluation normally afforded to new trial measures in child health research. For the second objective, we have gone some way towards establishing that the MLQ has psychometrically robust elements. The 45 Likert scale items have been comprehensively examined and the four-factor solution identified through the EFA was subsequently tested separately on the baseline and 12-month data sets B.