Paincognition and suffering

Aya NakaeOsaka University Graduate School of Medicine, Department of Anesthesiology

Outline

What is pain? My researchWhat is “schizophrenia?” The correlation between schizophrenia and chronic pain Results Future plans

The definition of pain

Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms of such damage.

What is pain? (Simple cases)

1. Tissue damage occurs.2. Inflammation change occurs.3. As a result, patients feel pain.4. Pain disappears with the scar.

What is pain? (Difficult cases)

Some patients feel pain for a long time.

Many such patients feel more pain than predicted by tests.

Patients are unable to work.

Components of pain

Pain behaviours

Suffering

Perception of Pain

Nociception

1.Nociception2.Perception of Pain3.Suffering4.Pain behaviours

Nociception

Nociception

Perception of pain

The message is received by the brain and pain is perceived because of the way, the brain works in individuals.

Perception of Pain

Suffering

Negative andemotional reactionscaused by pain depression fear anxiety stress etc

Suffering

Pain behaviours

Saying” Ouch!!” Grimacing Limping Lying down Recourse to health

care Refusing work

Pain behaviours

The purpose of our research

The clarification of the process from pain perception to suffering through researching patients with schizophrenia and chronic pain.

Why patients with schizophrenia?

They are less sensitive to painruptured appendix perforated bowels peritonitis painless myocardial infarctionChronic pain is rare.

??

?

Why are they less sensitive?

Cognitive impairment Affective impairment Attention deficiency

Why patients with schizophrenia?

Pain Pain

Suffering Suffering

Pain Behaviour Pain Behaviour

Patients with chronic pain Patients with schizophrenia

Degree of pain suffering

StrongWeak

Schizophrenia Normal Chronic painSchizophrenia is a human model considered to be the opposite of

that with chronic pain.

Methods

Chieko TakamuraChieko was an artist who created many works of art after suffering with schizophrenia.

Participants

Patients with schizophrenia: - Diagnosed using DSM-IV criteria - Exclusion criteria 1) 　 cannot understand the test 2) 　 cannot answer the questionnaire

accurately　 Healthy control: - Not diagnosed with any psychiatric illnesses

Clinical assessments of patients

Symptoms of schizophrenia - Positive and Negative Syndrome Scale (PANSS) Medication - Chlorpromazine equivalents History

patient’s age on diagnosis diabetes self injury etc.

Pain assessments

Electrical stimulation - minimum detection threshold - pain detection threshold - pain tolerance Thermal stimulation - warm/cold detection threshold - heat/cold pain threshold - heat/cold tolerance

Expression of pain

McGill Pain Questionnaire (short form)

S-PRI: Subjective assessments A-PRI: Affective assessments T-PRI: Total assessments Visual Analogue Scale (VAS)

Results

This picture by Norwegian artist Edvard Munch is said to show the hallucination of a patient with schizophrenia.

Participants

　 Patients Controls

Total 39 32

Male 15 15Female 24 17

Age 　 Patients (MeanSEM)

Controls (MeanSEM)

Total 37.2 (±12.9) 35.7 (±9.8)

Male 37.3 (±14.9) 36.3 (±9.1)

Female 37.2 (±12.2) 35.1 (±10.7)

Discussion

Self-portrait with bandaged ear.Vincent van Gogh, who was troubledBy mental health, cut off his own ear.

Causes of Schizophrenia

Genetic Intermediate phenotypes Prenatal Social Others

Eugen Bleuler (1857-1939) coined the term "Schizophrenia" in 1908.

What is a phenotype?

Gregor Johann Mendel

The phenotype

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HPT

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Patients Control

The data showed potential phenotype groups in schizophrenia.

Analgesic effect of antipsychotics?

Dopamine D2 antagonist (traditionalAntipsychotics) and opioids　　　　　　　 Neuroleptic analgesia

Less sensitivity to pain due toantipsychotics’ analgesic effects?

Not dosage dependent

Severe schizophrenia?

Less sensitivity to pain due to the symptoms of schizophrenia?

No correlation between symptoms and pain sensitivity shown in PANSS (schizophrenia syndrome scale) data.

Schizophrenia

Normal

HPT and pain suffering

StrongWeak

SchizophreniaNormal

Chronic pain

Degree of pain suffering

Heat pain threshold

High Low

Patients with normal heat pain thresholds

have a normal degree of suffering?

? ?

Patient 1: Confident against pain!!

History of spinal contusion injury(SCI)

No pain No analgesics

High Low

Heat pain threshold

Patient 2: Always feels knee pain

Feels pain due to osteoarthritis in the knee.

Receives general therapy for knee pain

High Low

Heat pain threshold

Patient 3: Feels pain but ・・・・・

History of SCI with paralysis She feel pain. She looks free from pain

High Low

Heat pain threshold

Schizophrenia

Normal

HPT and pain suffering

StrongWeak

SchizophreniaNormal

Chronic pain

Degree of pain suffering

Heat pain threshold

High Low

Why don’t need analgesics?

The last patient felt pain. She didn’t want her pain treated.

Pain is an unpleasant sensory and emotional experience

Her pain probably was not so unpleasant to require treatment.

Schizophrenia less sensitive to pain

1. Sensory insensitivity2. Less suffering due to

the noxious stimuli

? ???

?

Future plans (1, 2, 3 ・・・・ )

John Forbes Nash, Jr. is an American mathematician who received a Novel Prize for his works in game theory.Nash is the subject of the Hollywood movie “A Beautiful Mind”. The film focuses on Nash's mathematical genius and his struggle with schizophrenia.

1. Detailed evaluation of sensitivity

2. fMRI study

Participants Patients with schizophrenia not suffering

from pain and Controls Pain task 15˚C, 45˚C , 50˚C stimulation lasting 20s Analyzing the areas which

contribute to suffering

3. Other possible imaging studies

Dopamine Glutamate

Significance : Area detection

Area detection

Evaluation of degree and treatment

Molecular mechanism

Direct stimulation

therapy

Significance : Genes

Target gene

Molecular mechanism

New analgesic and anesthetic

Progress in schizophrenia

research

Acknowledgements

Department of PsychiatryRyota Hashimoto and his colleaguesNihon Koden CooporationSyogo Maeda & Tomoko OkuDepartment of Pain MedicineMasahiko ShibataGraduate School of DentistrySyoichi IshigakiDepartment of AnesthesiologyAll my colleagues