Recent advances inunderstanding mentalillness and psychotic - PDF document

Recent advances inunderstanding mentalillness and psychotic A rt by The British Psycgical SocietyDivision of Clinical Psyc June 2000St Andrews House48 Princess Road EastLeicester LE1 7DR,UKTel 0116 254 9568Fax 0116 247 0787E-mail mail@bps.org.ukhttp://www.bps.org.ukIncorporated by Royal CharterRegistered Charity No 229642 The BritishPsychological Society Co-ordinating Editors:Dr Peter KindermanAnne CookeChair of Working Party:Professor Richard P BentallWorking Party:Professor Richard BentallProfessor Mary BoyleProfessor Paul ChadwickAnne CookeProfessor Philippa GaretySimon GelsthorpeDr Anne GoodwinLucy JohnstoneDr Peter KindermanProfessor Elizabeth KuipersDr Steve OnyettDr Emmanuelle PetersProfessor David PilgrimProfessor Til WykesWith further contributions from:Dr David Harper Professor Tony Lavender Dr Rufus MayDr Mike Slade June 2000ISBN:1 85433 333 XAny part of this document may bereproduced without permission butwith acknowledgement. PageExecutive summary4Part 1:Understanding mental illness 8Section 1:What this report is about Ð introduction8Section 2:How common are these experiences?11Section 3:Prognosis Ð course and outcome14Section 4:Problems with ÔdiagnosisÕ in mental health16Section 5:A continuum between mental health and mental illness18Part 2:Causes21Section 6:The complexity of psychotic experiences21Section 7:Biological factors in psychotic experiences24Section 8:Life circumstances and psychotic experiences28Section 9:Psychological factors in psychotic experiences31Part 3:Help and treatment35Section 10:Assessment35Section 11:Medication for psychotic experiences38Section 12:Psychological interventions for psychotic experiences44Section 13:Risk and psychotic experiences49Section 14:Social exclusion53Section 15:Implications of this report for mental health services58Contents 3 Executive summary wevy,e.ewev 4 5 y,y,evweveve,e,Section 11:Medication for psychotic eev Executive summary(cont.) .Twy can have serious unwanted effects (Ôside effwhich for some people can be worse than the originaly,pyDespite the effeness of psychological intervand the fact that they appear to be cost-effe,ces are needed,y for training.wev 6 lService users should be acknowledged as experts ontheir own experiences.lThe use of coercive powers (for instance detentionunder ÔSectionÕ and forcible treatment) should not befurther extended.lPsychological therapies should be readily accessible topeople who have psychotic experiences.lAll mental health workers should be aware of and usea psychological understanding of psychoticexperiences.lTraining is needed nationally to educate all mentalhealth staff about the information contained in thisreport.It should also be part of the basic training of allthe mental health professions.lPrejudice and discrimination against people withmental health problems should become asunacceptable as racism or sexism. 7 Part 1:Understanding mental illness Keweve,e.vee.w, 8 ,fe.When I was an inmate in the hospital I was very confused andsometimes suicidal.I was feeling very desperate and self-harming roughout this time I was battling with the.They would shout Staff got really angry withme when I cut myself and often ignored me,or greeted me withsarcastic comments.Once they sent me to the Accident andy Department on my oI was finding it hard todistinguish between what eyone else said was reality and thedment of the voices.The voices were making it diffto do anything.The TV was talking to me.People were fme and they could see inside my head and read my thoughts.s.y.weve,wev 9 Part 1:Understanding mental illness (cont.) gyy,psychotic experiences have been thought of assymptoms of Ômental illnessÕ such as schizophrenia ormanic deprand the people who experience themve been rred to as ÔpatientsÕ or y it has been suggested that there are other ways ofthinking about these experiences,and that,medical terms are not alys the only or best ones to use.Wey,w,my. 10 Key,As outlined elsee in this rtraditional psychiatricclassifications of psychoses and serious mental illnesses arenot necessarily consistent with psychological classificationsand descriptions.In order to describe the issues invy be useful to clarify the diffent roles of psychiatristsand clinical psychologists.Psychiatrists are medically traineddoctors who specialise in mental health.psychologists have an academic training in psychology,use this understanding of thought premotion andviour to understand and help people with personalDespite some diffpsychiatrists andclinical psychologists work closely together.because of their training and backgrpsychiatrists tendto understand mental health issues (including of coursepsychotic experiences) in terms of symptoms leading todiagnosis and try,because of their trainingand backgrclinical psychologists tend to see mentalhealth issues and psychotic experiences as problems whosecauses and solutions will be slightly diffent for eachClinical psychologists have,traditional classifications of psychological distress based onpsychiatric diagnosis,and have begun to suggest alternativveve 11 Part 1:Understanding mental illness (cont.) vewev,evove.Frevve,wevy,y,wevveevy. 12 y,a,fWe.Õe are people who have developed a very positiverelationship with the experience of hearing voices,and haveed without any psycic treatment or supporhave adopted a theoretical frame of rence (such as,r,the collective,or the spirituality of a higher consciousness) whichconnects them with others rather than isolating them:they havefound a perspective that offs them a language in which toe their exper.They enjoy a feeling of acceptance;own rights are rand they develop a sense of identityh can help them to make constructive use of theiriences for the benefit of themselves and others.Õ 13 Part 1:Understanding mental illness (cont.) Key people assume that a diagnosis of a psychoticillness means that the individuals must resign themselvto a life of illness and disability.In fact,the course andoutcome of psychotic experiences are vy diffent fent people.e.In fact,outcome is a complex phenomenon.Each persony make pror continue to have pron anumber of dimensions that are ry independent ofeach other.ÔClinicalÕ outcome concerns whether or notsomeone continues to have psychotic experiences.outcome is measured in terms of the quality of the personÕssocial rOccupational outcome rers to thes ability to sustain emploSometimes peoplewho continue to have seve and enduring psychoticexperiences nonetheless have normal lives in all othersuch as work and rOn the othersome people benefit from complete or pary from psychotic experiences but continue to find itdifficult to work (for example because of difficultyconcentrating) or experience difficulties in other areas suchas ry people find that the hardest part ofy is ovcoming prexpectations and the pre to subscribe to a Ôsick ry.Õ.ÕThe course and outcome of psychotic experiences are highly.Some people rver completely after only one,some people suffer from multiple episodes separatedby periods of complete or partial ry,and some ry affLong term fw-up studies indicatethat as many as a third of all people who have psychoticexperiences completely r,and that less than a quarremain permanently affMost people mighty hope to rver either completely or parafter a psychotic episode.y mental health wby definition only come into contact with people whoue to need their help (or for those who need help onlyy,at times when they need it) fall into the trapwn as the s illusionÕ.y assume that ry is 14 e and that most service users are liky to be dependenton services for the rest of their liv,although theree thousands of former service users who either no longerve psychotic experiences,or have found effe ways tocope with them and no longer need help from serrent service users rary have the opportunity to meetBecause of this both staff and service users are indanger of developing ov-pessimistic views about the future.ove. 15 Part 1:Understanding mental illness (cont.) KeExperiences such as hearing vholding unbeliefs and experiencing marked mood swings arey thought of as symptoms of mental illnesses ande described using terms from psychiatry Ðdelusions and mania.wevvee,y.y.y,The use of diagnostic categories inves two basicassumptions about consistency and usefulness.It is assumed,that people can be ry assigned to a pary Ð that two clinicians can agree on which categy to 16 y rwevwed that clinicians ofteneed about psychiatric diagnosis and that diagnosticpractices diffed from country to country.Clinicians haveput a great deal of efft into improving the consistency ofmost notably through the publication of specificuals which specify which symptoms an individual mve for a specific diagnosis to be made.The best-knoexample is the Fth Edition of the Diagnostic and Statisticalual of the American Psychiatric wev,these effts have had only limited successin normal clinical practice.A second set of assumptions about diagnostic categes their validity Ð whether they can be said to bey meaningful and useful.We can look at this issuein several way,the usefulness of a diagnosticy is shown by its ability to predict new obserthat cast light on the causes of a personÕs symptoms.F,a diagnosis of ÔmalariaÕ would suggest that theindividual has suffed a viral infand even that theperson has ry travelled to tropical countries.It alsotells you which treatment is liky to help and what theognosis is.Similar predictions have never been successfullymade from any of the psychosis categwevve,wev,r.Fy.y,ove. 17 Part 1:Understanding mental illness (cont.) Key,w,1e.In some cultures hearing voices and seeing visions isseen as a spiritual gift rather than as a symptom ofmental illness.y,y,.Pwey,I remember the time period just befe other people becameconcerned about me.I was not sleeping very well and weaming at work a lot.This daydreaming allowed me toescape from a dry job and a gally depressing set of.On one occasion I had to deliver a parcel byain from London to Manc.At Euston Station I lost myain tickminutes befe depare.At the time I wondered to 18 myself whether a man who moments earlier had brushed byme had picketed me.As the depare whistle blew Idecided to run around the barrier and managed to jump on tothe guars carre as the train was moving off.Thinking thatain officials might have seen me do this,I went into the trtoilet and ced my appearance in order to avoid rI used water to restyle my hair and ced my clothing ash as I could by putting my shirt on over my sspent the rest of the journey using my wits to avoid the tick.This was an exciting experience that had echoes of spyies I had enjoyed when I was young.I began to wonder ifanother passenger sitting near me was actually a plain-cain detective.I then returned to toying with spy scenarWhat if my feelings of being a spy really were true? I went backover the things that had happened.What if the pick pockwas a test of how resourceful I could be if I had to delivertant documents in difficult circumstances? What if thecompany I worked for was actually a secret government agMaybe I was not an office dogsbody at the beginning of a dulleer but an apprentice spy! On the return journey I camek down to earth when a diligent ticket collector insisted onwaiting until I had vacated the train toilet.He decided to let meoff the fine when I told him I was just an office junior.FrveSo-called ÔabnormalÕ experiences can be seen in healthy,wfunctioning individuals.For instance,10 to 15 per cent of therowveveeconceptualised as spiritually enriching.e isevÔspiritual giftsÕ which are to be reved to somepossible to have unusual experiences that are not necessarilyve, 19 Part 1:Understanding mental illness (cont.) .Õy,vee,,we. 20 21Part 2:Causes Key,e,y,eve is also a vy close relationship between ÔmindÕ andin that evy thought is both a brain-based evand a human experience.This means that it is vy difficultto draw clear lines between biological and psychologicalIt is also true that biological and psychologicalaspects can be more or less important for diffent people.For some people,it appears liky that biological factors aremost important in the development of their psychoticFor others social or psychological factors,the events they experience,seem more impore is little point in trying to identify one cause;trigger can be something ry minor,but the personÕsreaction or enonment sets up a vicious circle that causesthe problem to escalate.An example might be the way inwhich fears of oing madÕ might make hearing voices ae terrifying and distressing experience 22Part 2:Causes (cont.) veevy,wevy,ve.ev,w,eveve.e,y.e. 23 e,ÔWhen I was four (or five) my brother started sexually abusing.It started off as an innocent,even rted as an innocent act of morning cuddles,until Iaccidentally called him My father died when I was ay.My brother got very angry Ð so angry I cried Ð and saidmy fs death was my fault and the abuse was myIt was about this time,I think,that Jenny started tohate me,and other voices appearMy brother said that if Itold of what was going on,my mother would hate me,that shewould think I was dirty Ð rorcing what I already belieabout mI w,and still am,ied of her rwev 24Part 2:Causes (cont.) Kewev,fy,wevvewevThe stress-vulnerability model (which will be describedther later in this rt) suggests that both psychologicaland biological factors may leave some people morevulnerable than others to enonmental strthis is not,in itself,an explanation for psychotic experiences,it can help us to understand how both biological andpsychological factors may contribute to prwev 25 wevwevIn summary,genetic factors may be important in a vgeneral sense,but the existence of a specific geneticcomponent to the various psychoses is not as clearlyestablished as is sometimes rMost of the studiested are evidence for a combination of genetic andonmental influences.e may be rvant non-specific hery factors such as temperamental sensitivity.ovwevy, 26Part 2:Causes (cont.) e.y,wev.F,rveA complete list of all the factors that have been identifiedas potential causes of psychotic experiences would covy aspect of biological functioning.Recent rech in this area concluded that:ÔAlthough the conceptof schizophrenia has been in existence for nearly a centuryÉ there has been no identification of any underlying causalew findings stand the test of time,most ofthe pieces of this particular jigsaw appear to be missing,and it is not easy to make sense of those that are aen dÕ scientific findings fail to be r.Fe 27 e,wevFey,ovy.wevwevy, 28Part 2:Causes (cont.) Kevee,y,weve,ry,veThis model explains why some people develop prand others do not,even when they go through similarIt explains why extreme stress can lead topsychotic experiences in almost any.It helps explainy some people rver from psychotic experiencesfaster than others,and are less liky to experience arence of their prIt also offers theuing possibility of ry over time;as even thosewith the most difficult problems may be able to avoid orreduce the likelihood of further episodes by finding ways ofreducing their exposure to situations that they findy strThe model also acknowledges theidea of psychotic experiences being on a continuum withother psychological problems such as anxiety.y,it alsotries to explain the fact that people who are prone topsychotic experiences may have long periods of ry,but may develop new difficulties (ÔrpseÕ) at various times. 29 wev.Pe.e.veRecent rch has suggested that,as with otherdifficult family relationships in childhood andadolescence may be an important contributing factor fsome people,but not all.It is unliky that we will ever beable to say with any certainty exactly which combination of 30Part 2:Causes (cont.) in what prhas caused any one individualto develop psychotic experiences at a particular time.wev,revmyThe evidence is now fairly clear,and has been repeated ony occasions,that family membersÕ attitudes can affthe outcome for people diagnosed with schizophrenia orbipolar disore are two important aspects toThe first is that friends and res occasionally finddealing with some of the problems that can be associatedwith psychotic experiences (pary embary disruptive or socially withdrawn behafrustrating and difficult,and sometimes become critical ory hostile tods the individual.The second ris to find the changes vy upsetting and to try to lookafter the person rather as if they we a child again.this y ovedÕ reaction is understandableand can be helpful in the short term,during ry it canlead to dependence in the individual and exhaustion in the.Either or both of these attitudes in carers (i.e.criticism or ovement) have been described as essed EmotionÕ.If they become extry havebeen found to lead to poorer outcome and an increlihood of a return of psychotic experiences.In contrast,people living in more suppore,w ExprEmotion enonments tend to have a lower likelihood of areturn of psychotic experiences,better social functioning,and better outcome.y,r 31 Keo.People who have psychotic experiences sometimesappear to have difficulty understanding what other peoplemight be thinking,at least when they are distry,y,y.y.Feve.e. 32Part 2:Causes (cont.) y,key.Yy,.Foveveve 33 y.fewe. .Py,vey.ovve 34Part 2:Causes (cont.) 35 Keav.Fy,kepy. 36Part 3:Help and treatment (cont.) vepy.Fovy,y.e.e.wevy,s, 37 experience is not valued I cannot be whole.It is particularlydiscouraging to speak to some psychiatric professionals andhave my experience validated only as a particular and very sadblemish in an otherwise benign conception.This is no validationwhatsoever.I am not the one regrettable bacillus in theotherwise sterile supplies room.My experience is shared and isrelevant.156Peter Campbell Ð personal account10.2.8 Needs for careScales that measure an individualÕs needs cover a widevariety of different areas such as residential care andrelationships.Often individuals,their carers and staffdisagree about the levels of need and these scales can behelpful in making different perspectives clear so they canbe discussed. 38Part 3:Help and treatment (cont.) Ke.Twe,ewovy,.Õ.Õs, 39 evevwevavev.Õoleptics are not perfect try are notesÕ even though they may make psychoticexperiences less intense and distry do nothelp ev,and rary rve proleptic treatment cancause adverse effects (side effects) which can be seriousand distrThese include the f.F,my,y,evy.ewew 40Part 3:Help and treatment (cont.) few,mwevwev(c) For many people,the balance between the advantages ofoleptic treatment (for example,a reduction in theequency or intensity of psychotic experiences) and thedisadvantages (for example,erse effects) is a fine one.one study it was found that Ôside effectsÕ we asbothersome to people as their psychotic experiencesOther studies have found that people harbour a wide varietyof opinions about their drug trying from they positive to the unequivy negative 41 (c) Ps attitudes,side effects and response to trshould be monitored at regular intere are a nof simple standardised scales designed for this purposew.Weovwevy.e.,re.I know that some people find neuroleptics helpful,but for me themain effects were the negative ones often thought of as These included being considerably mentally slo 42Part 3:Help and treatment (cont.) well as r,Parkinsonism (trs in the arms and legsand shuffling of the fysical weakness and impotence.Iwas determined to come off them at the fst possible.At no point during my initial admission was Iconsulted at all about the medication I was being given.told me about possible side effects or gave me a chance toe in decisions about my trMy experience was ofbeing treated as a second class citizwho was expectedobediently to take drugs that felt to me very noAs the staff were making decisions about me without listening tome I decided not to trust them or their decisions.I wdetermined to withdraw from the medication at the fst available.It was a very difficult thing to do as the withdrects lasted for many months and included states that were interpreted by some as psychotic r.It wat least partly as a result of this that I had two further hospitaladmissions bef,at the third attempt I managed toaw successfully from the medication.y,.Õ.ÕÔI find Lithium (and carbamazepine) hamper oneÕs ability tothink normally.Between episodes I prer to do without.way there is more joy in life.The drugs leave you without fand it is very difficult to be in touch with oneÕs inner self.Õwevy, 43 py.y,e.Tr 44Part 3:Help and treatment (cont.) Kepye,wevpy,py 45 vey,wev,rwevpy.pyCBT shares with other apprhes such as psycy and psychoanalysis an emphasis on the meaningof an experience for the individual.CBT and other therapies aimto help people understand and possibly ce the ways thatthey underet and respond to experve 46Part 3:Help and treatment (cont.) w,.P.PThe collaborative relationship I have with Paul gives meidence that my ideas,as well as his,e imporI get tosay what I want to work on Ð I have some power in thisPaul gives me fk and some idea of his rand tells me what areas he might like us to co.He does thiswhilst giving me a lot of power and I feel that I am in contrTalking about the Ôvoices thingÕbecame open and normal.It hasnot been shied away frWe have discussed:e the voicescome frthe effect they have on me,w the voices feed on myesent feelings and how I can,tially control them.e.py,y,py 47 y,vewevevpy.y.y.,fkey,Try, 48Part 3:Help and treatment (cont.) ovThe focus of rehabilitation tends to be the social,and occupational disabilities that sometimes accompanypsychotic experiences.Four types of help have often beensocial skills training,e rpeople to engage in purposeful activity and prot in the personÕs enw.wevpywevve.y. 49 Kewevweve,f,mwevew.Wy.,av 50Part 3:Help and treatment (cont.) .Tge,Õs,.Õe,.Pwev 51 e,ovpy.ving aside neglect and abuse,long term residence ininstitutions can sometimes be harmfulen shorterm stays in acute psychiatric units may disrupts lives and r.What peopley like most about psychiatric inpatient units isving them.The recent Sainsbury Centre nationalaudit of such units described hospital care as .Pe.y, 52Part 3:Help and treatment (cont.) y,wev 53 Kee,y.vePeople with psychotic experiences who re apsychiatric diagnosis are excluded from many aspects ofsociety that others take for granted.This hawhether they live in hospital or in the comme significantly poorer than the rest of the populationand less liky to be in paid emploThe public ingeneral is prejudiced against people who are identifiedas y illÕ.It is not surprising,e,people with a diagnosis of schizophrenia tend to havesmaller social networks than those of their.Those who have had repeated hospitaladmissions have smaller networks than those with onlyone admission.A study of people attending long-termpsychiatric day care found that about one-third did notuse any reational community facilities (elibraries and public enterA small butsignificant percentage did not even use public ser(such as shops,public transport and the Post Office)that are essential for independent community livings, 54Part 3:Help and treatment (cont.) ,r.Po,y,rovw,e.en the negative attitudes that exist tods mentalsome hospital closure programmes have includeda public education component,in an attempt to improvethe social integration of the people being dischargedinto the commchers have eeducational campaign comprising information (both 55 written and by video),social events and infdiscussions associated with the opening of staffed grhouses for people discharged from long-stay hospital.The effect of the programme was to increase contacteen staff and residents of the new facility and theirneighbours that resulted in a lessening of fearful andrejecting attitudes within the comm,as a rof the education programme more ex-patients rving made contact and friendships with theiry,wwevag,Õ.Õ 56Part 3:Help and treatment (cont.) y,e.e.wev.F.Tow, 57 ,fwevov,w.Ty,y.ov 58Part 3:Help and treatment (cont.) KeovovewevThe final section of this rt outlines what a serbased on these principles might look like,and suggests theection in which current mental health services should.The emphasis of this section is on values,principles and works of understandingÕ.As this rhas demonstrated,these are as important as the specificeatments or types of help which services proy,y, 59 One important implication is that pressionals and othermental health wers should not insist that all service usersaccept any one particular framework of understanding.for example,that pressionals should not insist thatpeople agree with their view that experiences such as suchas hearing voices and holding unusual beliefs are alsymptoms of an ying illnessÕ such as schizophrSome people will find this a useful way of thinking abouttheir difficulties and others will not.s,e.e,e,I donÕt think they treat black people the same as they treat whitepeople É We have a diffent culture from white people,because we talk loud and we laugh out loud Ð our behaviour ise loud than white people Ð they think it is mental illness. 60Part 3:Help and treatment (cont.) .Fe.y,y,,f 61 wevavw. 62Part 3:Help and treatment (cont.) wevw.,ry.y,y,e,e,.Py..T 63 e,ewwÉnone the less to be said that for this ...to be maintained overyears,weve,py.pywevweve.y..But that is not compliance,rather collaborative alliance.Only once in 15 ys of psycic interand at the ageof 36,was I able to find someone who was willing to listen. 64Part 3:Help and treatment (cont.) oved a turning point for me,and from this I was able to brout of being a victim and start owning my exper.The nuractually found time to listen to my experiences and fays made me feel welcome,and would make arrso that we would not be disturbed.She would sh off herbleeper and take her phone off the hook,and sometimes,e were people outside her rshe would close the blinds.These actions made me feel at ease.She would sit to one sideof me instead of across a deskÉSlo,as trust grew betweenus I was able to tell her about the abuse,but also about thevoices É At last I had found someone who rgnised the painI was fShe helped me realise that my voices were part of,and had a purpose and validity.Over a six-month perwas able to develop a basic strategy for coping.The mosttant thing that she did was that she was honest Ð honestin her motivations and in her responses to what I told her ÉThanks to the support this worker gave,I have been able tovelop a re of coping mecy people find either medication,talking treatments orboth helpful.wev,this is not the case for evyone andeven for those who do,help with things like housing,,work and maintaining social roles can often bey important in their ry.vices should beflexible enough to offer each individual what he or she findsmost helpful,and as outlined in Section 15.3.2,this will be practical help (for example with accommodationor employment) rather than eatmentÕ or ,wy,y,,P. 65 y.w..T.ATrAll treatments have the potential to do harm as well as gand so wers need safd the principle of infvice users should have access to the sameormation that is available to wers (rch rfor example),and should have the right to refuse trincluding medication,ECT and psychological interv 66Part 3:Help and treatment (cont.) e,In the context of my own experiences of psychosis I am eready to support consideration of alternative models of caree there is less emphasis on coercive trI still wup from nightmares that I have been readmitted and highlymedicated against my will.In my community work I rgnise thesame fear in clients who are desperate to not be misunderor judged hospitalisable.This fear of losing oneÕs freedom is amassive obstacle to collaborative mental health care.possible there I believe it is important to not see sectioningand locked wds as given and fundamentally necessary.Dr Rufus May Ð personal account 67 y.y,ve.ovwevy,y,y,awev.We 68Part 3:Help and treatment (cont.) e.veTrrI was listened to seriously and attentively;my,ry.y.y,y,e.y.,f 69 weve,wevy,y,y, 70Part 3:Help and treatment (cont.) ps even more important than the availability of specifictalking treatments is the need for all mental health wto be ae of the information contained in this ry wers are unae of the recent advances thatve been made in understanding psychotic experiences,and are unfamiliar with the rch described in thisIn parers still view psychoticexperiences as fundamentally incomprehensible andue to concentrate effts to help on rving orlessening them.A fundamental message of this rt is thatpsychotic experiences are meaningful and understandable insimilar ways to other human experiences or beliefs,and canbe aoached in the same way.e,ev.Fe. ,ry.Fe,e.ve.TwTre.Fovy, 71 ovve.WeThat one day I will be able to talk about my mental healthoblems and attract no more than interest in those around me.e,r 72Part 3:Help and treatment (cont.) 73 rey,y,y.Tow,F.C.,Dy,y,y.Towvey.,D&Wy,wYwYy.y,.WwYy.y,FoW.y,ve,p,p,Wy,y,s.y,y,y,wYy.y,y,y,y.wYD.y. 74References (cont.) y.e..WwYy.y,owe,Ty,y,,Py,y,C.wY,Py,C,P.D.ry,Cy,rey,Dy,y.y,D.W.y.py..Ky,,C,pD.,CwYs.wYD. 75 e,y,y,y,,Py,y,y,y,y,y,y,y,y,y,y,W.y,D.y,,D..Foy.roy,e,C.C.,Dpy.D.T.Wy,C.s.wY,CwY 76References (cont.) ,Py,Dy,,DP.Toy,P.e,P.P.y,y,P.T.Wy,y,D.TrT.,W.y,y.,WV.y,y,,pwYT.y,Ppy.y,Py,,D.&W,Pe,py.y,C.y,y,Py,,Oy,&Vy,,V.y,,C.y,D.y,,pow,TC.y,y,D,D,D,D.&Ty, 77 y,D.,Cy,y,y,D.P.y,y,y,y,D.w,.Tae.,Te,my,.&Ay,y,O.D.y,wey,y,y,y,e,y.w.,TC.y,y,D.,P,DD.y,C.y,,Ty,.&Vy,.&,Pw,y,wYD.o,y,D,Py,P.y,y,C.&y,w.w,y,e,P 78References (cont.) ,CC.,PD.,Py,DP.we,C.F.P.we,Cy,,PFo,DD.y,C.y,,Ty,&TD.Fo,D,Py.&Trow,P.y.,PFo,DD.y,C.y,y,Fo,D,PP.y,C.y,,Ty,Fo,D,PP.y,C.y,y,VF.y,C.&y,w.w,y,P.C.y,ry,P.y,ry,PevP.y,,D.D.y,C.D.y,C.D.,CwYC.&TT..Fe,y,roC.y,.&W,Cy,T.Twy,T.&W 79 y.,VD.,CC.r,P.Toy.T.D.D.TwT.Ta,Py,,CD.C.y,ey,,Ty,,D.e.y,y,,Jey,,Ty,ToT.o,y,y,y,,C.e,y,P.evy,P.y,y.wY.&veP.,P.e,e,C.D.y,P.D.y,vey. 80References (cont.) w,y.y.wYF.y,,D,DTa,DPowy,P.Fre,T.y,,ry,e,T.y,r,P.,Pow,y.y.y.Ta,DPowy,P.veD.y,D.y,y,P.y,Cy,D,Cry,PP.P.y,Try,FrV.e.V.V.e.V.P.V.e.V.y.,Fy, 81 y,D.y.D.&Trow,P.,Py,D.,P.P.w,V.,D.e.,D.P.&P.P.C.y,9y,y,D.y,P.y,D.y,,Py,P.,pP.w,V.y,DC.&P.y,P.y,W.D.,D.D.y,ovwY 82References (cont.) y.y.y,y,y.