Chatper 18: Biopsychology of Psychiatric Disorders

Challenges of Diagnosis

-Difficult due to lack of clear biological markers. It requires judging if psychological function is pathological or normal variation

–Patients with the same disorder often have different symptoms

–Patients with different disorders share many of the same symptoms

DSM-5

Mental Health Bible

Schizophrenia

•means splitting of mental function (the shattering of the mind). 

•difficult to define accurately due to complex, diverse symptoms.

•Symptoms overlap with other psychiatric disorders and change over time.

Positive Symptoms of Schizophrenia

•Delusions: Examples include delusions of being controlled, persecution, and grandeur.

•Hallucinations: Often imaginary voices making comments or commands.

•Inappropriate Affect: Inappropriate emotional responses to events.

•Disorganized Speech or Thought: Illogical thinking and peculiar idea associations.

•Odd Behavior: Such as talking in rhymes and difficulty with everyday tasks.

Negative Symptoms of Schizophrenia

•Affective Flattening: Reduced emotional expression.

•Avolition: Lack or reduction of motivation.

•Catatonia: Remaining motionless in odd positions for long periods.

Genetic Aspects of Schizophrenia

–Concordance rate of schizophrenia in identical twins is about 45%; in fraternal twins or siblings, it is about 10%.

–Schizophrenia linked to multiple genes, no single gene causes it alone.

–Genetics relate to brain development and neuron physiology.

Epigenetics Influences on Schizophrenia

–Early life factors like birth complications and maternal stress impact development.

–These may alter neurodevelopment through epigenetic mechanisms in genetically susceptible individuals

Neural Bases Meta-Analysis of Brain Imaging

1.Brain volume reductions in areas like the hippocampus even in high-risk individuals before diagnosis

2.Extensive brain changes already present at first diagnosis

3.Brain changes continue to progress after initial diagnosis

Neural Bases of Modern functional brain imaging

-Is revealing insights into functional connectivity:

-Connectivity patterns change during hallucinations in schizophrenia patients

-Intrinsic connectivity patterns may predict treatment response to antipsychotics

Depression

–Characterized by severe depression, anhedonia, cognitive impairment, lack of appetite, sleep problems, withdrawal, inability to care for self.

–Clinical depression diagnosed if it lasts over 2 weeks.

Reaction Depression

Caused by negative experiences

Endogenous Depression

No apparent external cause

Seasonal Affective Disorder (SAD)

–Related to reduced sunlight, prevalent in winter. Higher in Alaska (9%) than Florida (1%). Light exposure therapy is effective.

Peripartum Depression

Occurs during or after pregnancy, affects about 13% of pregnancies.

SSRI’s

Blocking of serotonin reuptake by fluoxetine

Effectiveness of Antidepressants

•About 50% of clinically depressed patients improve with antidepressants.

•Control groups show about 35% improvement.

•Net benefit from antidepressants is around 15% over control conditions.

•A 15% improvement is considered meaningful due to the debilitating nature of depression.

•Some antidepressants are more effective than others.

Repeated Transcranial Magnetic Stimulation (rTMS)

–Noninvasive delivery of magnetic pulses to the brain, usually targeting the prefrontal cortex.

High-Frequency rTMS

Stimulates brain activity (about five pulses per second).

Low-Frequency rTMS

Inhibits brain activity (less than one pulse per second).

Deep Brain Stimulation (DBS)

-Involves implanting an electrode to provide chronic brain stimulation

-The electrode tip is placed in the white matter of the anterior cingulate gyrus in prefrontal cortex

Bipolar Disorder

•Characterized by alternating periods of clinical depression and hypomania or mania. Mood episodes typically last weeks to months, not rapid alternations.

•Affects about 3% of the global population.

•High rates of attempted and completed suicide.

Hypomania

-Reduced sleep need, high energy, positive affect, talkative, energetic, impulsive, and confident.

Mania

•Extreme hypomania symptoms, delusions of grandeur, overconfidence, impulsivity, distractibility, often involves psychosis. Can lead to unfinished projects, unpaid bills, and broken relationships.

Bipolar I

Those who experience mania episodes

Bipolar II

Those who experience bouts of hypomania and depression

Mood Stabilizers

–Aim to treat depression or mania without increasing risk of shift to the opposite pole (from depression to mania or vice versa). 

–The mechanisms by which it works is still unclear

–Many drugs are also effective for treating epilepsy & schizophrenia.

Do not eliminate all symptoms and come with many side-effects

Lithium

–John Cade's experiments with guinea pigs led to discovering lithium's mood-stabilizing properties.

–Initially tested on manic patients with dramatic effects.

–Renowned for neuroprotective and anti-suicidal benefits.

Anxiety

Chronic fear/worry in the absence of direct threat, a common psychological response to stress

•Adaptive at normal levels, but disrupts functioning when severe (anxiety disorder)

•Associated with feelings of anxiety/fear and physiological stress reactions like rapid heartbeat, nausea, sleep issues

•Anxiety disorders are the most prevalent psychiatric disorders. Estimates of 14-34% of people suffering from an anxiety disorder in their lifetime

Generalized Anxiety Disorder (GAD)

–Persistent anxiety and worry about various activities or events.

–Often disproportionate to the actual likelihood or impact of the feared event.

Specific Phobias

–Intense fear or anxiety about specific objects (e.g., spiders, birds) or situations (e.g., enclosed spaces, darkness).

Agoraphobia

–Pathological fear of public places and open spaces.

–More incapacitating than most specific phobias, classified separately in DSM-5.

Panic Disorder

–Recurrent, sudden panic attacks characterized by intense fear and physical stress symptoms (e.g., heart palpitations, shortness of breath).

–Can occur in conjunction with other anxiety disorders like GAD, specific phobias, and agoraphobia.

Clinical Trials

–Conducted on human volunteers to assess drug efficacy and safety.

–Essential for validating new psychotherapeutic drugs before public use.

Phase 1: Safety Screening

•Tests drug safety in healthy volunteers.

•Begins with small doses, increased gradually.

•Halts if severe adverse reactions occur.

Phase 2: Testing Protocol Establishment

•Determines effective dosing and identifies potential benefits.

•Conducted on patients with the target disorder.

•Uses double-blind, placebo-controlled design.

Phase 3: Final Testing

•Large-scale efficacy confirmation.

•Involves many patients in double-blind, placebo-controlled trials.

•Requires two successful tests for regulatory approval.

Double-Blind Design and Placebo Controls

–Ethical concerns as some patients receive a placebo instead of the experimental treatment.

–Necessary for unbiased assessment of drug efficacy.

Active Placebos

–Need for active placebos to maintain the integrity of double-blind studies.

–Address the issue of participants guessing their treatment group based on side effects.

Duration of Clinical Trials

–Lengthy process frustrating for patients in need of new treatments.

–Balancing speed with safety and thorough evaluation.

Financial Conflicts and Impartiality

–Drug companies' significant investment may influence trial outcomes and impartiality.

–Concerns about the suppression of negative findings.

–Challenges in funding for rare disorders (orphan drugs) due to low profitability.