Psych 11

• Multidisciplinary Contributions to studying psychological disorders

  • Psychology
  • Biology
  • Biochemistry
  • Neuroscience
• Types of contributions


  • Clinical
  • Experimental
  • Practical
• Factors considered in studying psychological disorders

  • Genetics
  • Environment
  • Interactions
• Behavioural Disorders


  Traditionally classified as social, psychological, psychiatric, or neurological
• Behavioural disorders reflect on the assessment and treatment roles different professional groups play
• Potential causes of behavioural disorders

  • Genetic abnormalities/mutations
  • Abnormalities in nervous system development
  • Environmental and epigenetic effects that modulate genetic and developmental expression
• Classification systems for diagnosing behavioural disorders

  • World Health Organization: International Classification of Diseases (ICD-10)
  • American Psychiatric Association: Diagnostic and Statistical Manual of Mental Disorders (DSM)
  • National Institute of Mental Health (NIMH): Research Domain Criteria (RDoC)

  
• Diagnostic and Statistical Manual of Mental Disorders – 5th Edition (DSM-5)

  • Section 1: history of revisions and changes
  • Section 2: criteria for main diagnostic categories and other disorders
  • Section 3: assessment measures, criteria for disorders that need further research

  
• The DSM-5 has more focus on sociocultural considerations
• Criticisms of the DSM-5

  • Concerns with validity – describing symptoms not disorders
  • Some diagnostic criteria based on research, others based on committee determinations
  • High comorbidity between diagnoses
  • Still relies heavily on categorization rather than dimension models for many diagnoses

  
• Treatments for behavioural disorders

  • Behavioural treatments
  • Cognitive therapy
  • Neuropsychological therapy
  • Emotional therapy
• Behavioural treatments


  Focus on key environmental factors that influence actions, also effects the brain, therefore can be considered a biological intervention
• Behaviour modification


  Applies principles of learning, e.g. systematic desensitization
• Cognitive therapy


  Addresses thoughts that affect emotions and evaluations before action, e.g. identify and replace self-defeating patterns
• Neuropsychological therapy


  Retrain individuals to use lost processes, strengthen existing ones
• Emotional therapy


  Gain insight into emotional states and the effects they have, also known as talk therapy or psychotherapy
• Major categories of psychiatric disorders

  • Anxiety disorders
  • Mood disorders
  • Psychoses
• Schizophrenia


  Psychiatric disorder assumed to be due to atypical brain activity or function
• Positive symptoms of schizophrenia

  • Delusions: beliefs that distort reality
  • Hallucinations: distorted perceptions
  • Disorganized speech: incoherent statements
  • Disorganized behavior or excessive agitation
• Negative symptoms of schizophrenia

  • Absence of some normal response
  • Blunted emotions or loss of interest and drive
  • Catatonic behavior
• Subtypes of schizophrenia


  • Type I: Predominance of positive symptoms, pathological extremes
  • Type II: Predominance of negative symptoms, absence of normal reactions

  
• Concordance of 0.80 in identical twins for schizophrenia, indicating a strong genetic role, but environmental factors must also play a role

  
• About 300 different mutations on 10 different genes predispose an individual to schizophrenia, and these tend to be genes linked to brain development, but not all genes are found in all populations

  
• Schizophrenia is often diagnosed early in life, suggesting a link to development
• Brain features associated with schizophrenia

  • Enlarged ventricles and a thinner cortex, especially in the medial temporal regions and frontal cortex, suggesting cell loss occurs in these areas
  • Haphazard direction of hippocampal neurons, associated with alterations in the temporal region and the frontal cortex
• Neurochemical abnormalities associated with schizophrenia

  • Decreased dopamine metabolites in cerebrospinal fluid
  • Increased striatal D2 receptors
  • Decreased expression of D3 and D4 mRNA in specific cortical regions
  • Decreased cortical glutamate
  • Increased cortical glutamate receptors
  • Decreased glutamate uptake sites in cingulate cortex
  • Decreased mRNA for synthesizing GABA in prefrontal cortex
  • Increased GABAA−binding sites in cingulate cortex
• Dopamine hypothesis


  Theory that schizophrenia involves high dopamine activity
• Aberrant salience hypothesis


  Suggests that heightened levels of dopamine increase attentional and motivational circuits to make ordinary environmental features seem significant
• However, dopamine deficiency and dopaminergic drugs being ineffective in many cases suggests the dopamine hypothesis is incomplete
• Glutamate theory


  Hypofunction of NMDA receptors leads to increases in glutamate, which in turn increases dopamine, producing positive and negative symptoms of schizophrenia
• Treatments for schizophrenia


  • Antipsychotic drugs
  • Electroconvulsive therapy
• Antipsychotic drugs


  Decrease action of dopamine, reduce positive symptoms of schizophrenia (e.g. delusions and hallucinations) but have little effect on negative symptoms, can cause tardive dyskinesia
• Electroconvulsive therapy


  Began with observation that schizophrenia and epilepsy rarely occur together, useful in treating severe depression, effects can be immediate, 60-70% improve
• Stress


  Used to refer to a range of concepts from external environmental stimuli to internal experiences and bodily responses
• Stressors


  External stimuli and events that represent a perceived potential for harm, loss, damage, challenge, or other deviations from a balanced state
• Stress responses


  Internal integrated psychological (cognitive) and biological responses to stressors that then work to restore a balanced state

  
• Diathesis-stress model


  Theory that mental and physical disorders develop from a genetic or biological predisposition for that illness (diathesis) combined with stressful conditions that play a precipitating or facilitating role
• Hypothalamic–Pituitary–Adrenal Axis


  Controls production and release of hormones related to stress

  
• Biological response to stress

  1. Amygdala > hypothalamus releases corticotropin-releasing hormone (CRH)

  2. CRH > pituitary gland releases adrenocorticotropic hormone (ACTH)

  3. ACTH > adrenal glands release cortisol
• Excessive cortisol can negatively influence the brain if stress is intense, damaging feedback loops the brain uses to turn off the stress response