Delusions and Delusions and hallucinations: theory hallucinations: theory

and treatmentand treatmentProfessor Max ColtheartProfessor Max Coltheart

Inaugural ARC Federation Fellow Inaugural ARC Federation Fellow &&

Scientific Director, Macquarie Centre for Cognitive Science, Scientific Director, Macquarie Centre for Cognitive Science, Macquarie UniversityMacquarie University

Brain and mind Brain and mind disordersdisorders

One of the brain and mind One of the brain and mind disorders:disorders:

schizophreniaschizophrenia

The symptoms of The symptoms of schizophreniaschizophrenia

Positive symptoms:Positive symptoms:•• DelusionsDelusions•• HallucinationsHallucinations•• Disorganization of thoughtDisorganization of thought

Negative symptoms:Negative symptoms:•• Lack of motivationLack of motivation•• Lack of emotionLack of emotion•• Little social contact with other peopleLittle social contact with other people

Some basic facts about Some basic facts about schizophreniaschizophrenia

•• One person in 100 will experience a One person in 100 will experience a schizophrenic episode during their lifetimeschizophrenic episode during their lifetime

•• No method of prevention knownNo method of prevention known•• No cure knownNo cure known•• Very little known about cause: genetic Very little known about cause: genetic

factors and stressful life events are factors and stressful life events are involvedinvolved

•• 25% will have only one episode; 40% 25% will have only one episode; 40% will have recurring episodes; 35% chronicwill have recurring episodes; 35% chronic

Treating schizophreniaTreating schizophrenia

•• These drugs have powerful sideThese drugs have powerful side--effectseffects•• Patients often donPatients often don’’t take their t take their

medication because of these sidemedication because of these side--effectseffects•• Drug treatment does not target specific Drug treatment does not target specific

symptomssymptomsIs there a treatment method that avoids Is there a treatment method that avoids

these problems yet can help?these problems yet can help?

Most commonly treated with antiMost commonly treated with anti-- schizophrenic drugs. Problems:schizophrenic drugs. Problems:

Our Belief Formation Our Belief Formation projectproject

Positive symptoms of schizophrenia:Positive symptoms of schizophrenia:•• DelusionsDelusions•• HallucinationsHallucinations

Project aim: to discover their causesProject aim: to discover their causes

Causes unknownCauses unknown

What is a delusion?What is a delusion?

Delusional disorders: Delusional disorders: Some examplesSome examples

• Capgras delusion: “My wife has been replaced by an impostor”• Fregoli delusion: “I am being followed around by people I know, but I can’t recognise them because they are always in disguise”• Cotard delusion: “I am dead”• Alien control delusion: “Other people can cause my body to move against my will”• Asomatognosia: “This arm (the patient’s left arm) is not my arm, it is yours”

and . . .

MirroredMirrored--self self misidentification:misidentification:

Patient TH, an elderly man who subsequently showed the symptoms of dementia, believed that the person he saw when he looked in the mirror was not him, but some stranger who looked very like him.

Why?

What has caused What has caused THTH’’ss delusion?delusion?

To solve this problem, answers to two To solve this problem, answers to two questions are needed:questions are needed:

•• Where did this idea come from in Where did this idea come from in the first place?the first place?

•• Once the idea occurred, Once the idea occurred, why did why did the patient continue to believe itthe patient continue to believe it even even though everyone was telling him it wasnthough everyone was telling him it wasn’’t t true?true?

Where did the idea come Where did the idea come from in the first place?from in the first place?

We discovered that this patient had lost all We discovered that this patient had lost all knowledge about how mirrors work. For knowledge about how mirrors work. For him, a mirror was just like a window.him, a mirror was just like a window.

Anyone you see through a window is in a Anyone you see through a window is in a different part of the world from you.different part of the world from you.

Therefore this person canTherefore this person can’’t be you.t be you.

Why didnWhy didn’’t he give up t he give up this bizarre idea?this bizarre idea?

WeWe’’ve found that ve found that this region of the this region of the brain is needed for brain is needed for us to be able us to be able to to judge beliefs judge beliefs against evidence.against evidence.Patient had damage Patient had damage to this region.to this region.

What caused the delusionWhat caused the delusion•• Where did this idea come from in the Where did this idea come from in the

first place?first place?Answer: a problem with Answer: a problem with perceptionperception : loss of : loss of

ability to deal with mirrorsability to deal with mirrors•• Why did the patient continue to Why did the patient continue to

believe the idea?believe the idea?Answer: A problem with Answer: A problem with beliefbelief: loss of ability : loss of ability

to judge beliefs against evidenceto judge beliefs against evidence

Our general theory of Our general theory of delusiondelusion

Two factors must always be present for Two factors must always be present for delusion to occur:delusion to occur:

•• Some problem with Some problem with perceptionperception -- this this produces the delusional idea in the first place; produces the delusional idea in the first place;

•• Some problem with Some problem with belief evaluationbelief evaluation: : this makes the patient unable to give up the this makes the patient unable to give up the belief.belief.

Our theory Our theory successfully explains successfully explains all of these delusions:all of these delusions:

• Capgras delusion• Fregoli delusion• Cotard delusion• Alien control delusion• Asomatognosia• Mirrored-self misidentification

ThatThat’’s it for the theory: s it for the theory: now, what about the now, what about the

treatment?treatment?

What about treatment What about treatment of delusions?of delusions?

Our case MF: a highly successful Washington lawyer, aged 69, who after a head injury developed the firm belief that his wife was not his wife but a different woman, a past business partner.

A conversation with MFA conversation with MFNora: “If this lady isn’t your wife, why is she

wearing a ring just like the one you told me you bought for your wife?”

MF: “She must have gone to the same shop and got another one just the same”.

Nora (takes the ring from the wife’s finger and shows it to MF) : “Well, it seems to have your wife’s initials engraved inside it. How would you explain that?”

MF (long pause): “I . . . don’t know how to explain that”.

A conversation with MFA conversation with MFAfter a week of conversations like this,

gently probing the evidence for MF’s belief, he relinquished the belief, and accepted that his wife was really his wife.

Implications of our theory Implications of our theory of delusion for treatment of delusion for treatment

Our theory:Our theory: two factors must always be two factors must always be present.present.

(a) Some problem with (a) Some problem with perceptionperception -- this this produces the delusional idea in the first place. produces the delusional idea in the first place.

(b) Some problem with (b) Some problem with belief evaluationbelief evaluation -- this makes the patient unable to give up the this makes the patient unable to give up the belief.belief.

Nothing can be done about (a). Nothing can be done about (a).

Implications of our theory Implications of our theory of delusion for treatment of delusion for treatment

Our theory:Our theory: two factors must always be two factors must always be present.present.

(a) Some problem with (a) Some problem with perceptionperception -- this this produces the delusional idea in the first place. produces the delusional idea in the first place.

(b) Some problem with (b) Some problem with belief evaluationbelief evaluation-- this makes the patient unable to give up the this makes the patient unable to give up the belief.belief.

But we find that (b) will respond to But we find that (b) will respond to persistent gentle discussions about persistent gentle discussions about evidence for the belief.evidence for the belief.

CognitiveCognitive--behavioural behavioural therapy therapy

This is a method for treating delusions and This is a method for treating delusions and hallucinations that is based on persistent hallucinations that is based on persistent gentle discussions about evidence for the gentle discussions about evidence for the belief.belief.

Some more details about the method . . .Some more details about the method . . .

CognitiveCognitive--behavioural behavioural therapy therapy

•• This method is based on persistent gentle This method is based on persistent gentle discussions about evidence for the belief.discussions about evidence for the belief.•• Good evidence that it can be effective in Good evidence that it can be effective in treating delusions and hallucinationstreating delusions and hallucinations•• It has had no theoretical basis until nowIt has had no theoretical basis until now•• Our theory supplies this theoretical basisOur theory supplies this theoretical basis•• Two major virtues: treatment is Two major virtues: treatment is symptomsymptom-- specificspecific and and drugdrug--freefree

WhatWhat’’s needed next s needed next •• We have discovered what causes delusions; We have discovered what causes delusions; complete project on what causes hallucinationscomplete project on what causes hallucinations•• Then collaborative research with clinicians, to Then collaborative research with clinicians, to develop CBT treatments based on our theories develop CBT treatments based on our theories and to test how well they workand to test how well they work•• And cognitive testing of atAnd cognitive testing of at--risk adolescents can risk adolescents can predict 50% of those who will have an episode predict 50% of those who will have an episode of schizophrenia: preventative CBT for themof schizophrenia: preventative CBT for them•• Outcomes:Outcomes:

DrugDrug--free treatmentfree treatmentReduced incidence of schizophreniaReduced incidence of schizophrenia