Psychological Disorders: Definitions, Classification, and Major Categories

Chapter 15: Psychological Disorders

Defining and Classifying Psychological Disorders

Psychological disorders are defined by persistent patterns of thoughts, feelings, or behaviors that are deviant, distressing, and dysfunctional. Accurate classification and diagnosis are essential for effective treatment and understanding of mental health conditions.

• Criteria for Abnormal Behavior: Maladaptive thoughts, feelings, or behaviors that cause distress, impair functioning, or increase risk of harm.

• Classification Systems: The Diagnostic and Statistical Manual of Mental Disorders (DSM-5-TR) is the primary tool for diagnosing and categorizing psychological disorders.

• Challenges: Cultural differences and the subjective nature of diagnosis complicate classification.

Historical Perspectives: Early views attributed abnormal behavior to supernatural causes, leading to practices like exorcism. The medical model, advanced by figures like Emil Kraepelin, shifted focus to symptom patterns and biological underpinnings.

• DSM Evolution: The DSM has expanded from 106 disorders in DSM-I to 19 categories in DSM-5-TR, reflecting advances in research and understanding.

• Criticisms of DSM: Subjectivity in diagnosis, symptom overlap, arbitrary thresholds, and cultural biases remain concerns.

Culture and Diagnosis

• Culture-Bound Syndromes: Some disorders manifest uniquely in specific cultures (e.g., ataque de nervios in Latin America, neurasthenia in China).

• Cultural Formulation Interview (CFI): Included in DSM-5-TR to improve diagnostic accuracy by considering cultural context.

• Epigenetics: Environmental factors (e.g., stress, poverty) can influence gene expression, affecting disorder prevalence across cultures.

Applications of Diagnosis

• ADHD in the Classroom: Diagnosed by persistent inattention, hyperactivity, and impulsivity. Accurate diagnosis enables effective treatment but raises concerns about overdiagnosis.

• Mental Disorder Defence in Law: Legal sanity is assessed by the ability to distinguish right from wrong (M'Naghten rule). The defence is rarely successful and requires careful psychological evaluation.

Personality and Dissociative Disorders

Personality Disorders

Personality disorders are enduring patterns of maladaptive, distressing, and inflexible behavior, typically traceable to adolescence or early childhood. The DSM-5-TR groups them into three clusters:

Cluster	Key Features	Disorders
A	Odd, eccentric	Paranoid, Schizoid, Schizotypal
B	Dramatic, emotional, erratic	Borderline, Narcissistic, Histrionic, Antisocial
C	Anxious, fearful	Avoidant, Dependent, Obsessive-Compulsive

Cluster A: Odd and Eccentric Behaviors

• Paranoid Personality Disorder (PPD): Persistent suspicion and mistrust of others without justification; heightened vigilance and stress responses.

• Schizoid Personality Disorder (SPD): Social detachment, lack of desire for close relationships, limited emotional expression.

• Schizotypal Personality Disorder: Discomfort with close relationships, eccentric thoughts and behaviors, possible genetic and prenatal influences.

Cluster B: Dramatic and Erratic Behaviors

• Borderline Personality Disorder (BPD): Intense emotional swings, unstable relationships, impulsivity, often linked to early trauma.

• Narcissistic Personality Disorder (NPD): Inflated self-importance, need for admiration, fragile ego, lack of empathy.

• Histrionic Personality Disorder (HPD): Excessive attention-seeking, dramatic and flamboyant behavior, high heritability.

• Antisocial Personality Disorder (APD): Disregard for others' rights, lack of empathy, impulsivity, often resistant to treatment. Psychopathy is a severe subset, diagnosed with the Hare Psychopathy Checklist-Revised (PCL-R).

Cluster C: Anxious and Fearful Behaviors

• Avoidant Personality Disorder (AvPD): Fear of rejection, social inhibition, heightened amygdala response to negative stimuli.

• Dependent Personality Disorder (DPD): Excessive need for care, difficulty making decisions, fear of abandonment.

• Obsessive-Compulsive Personality Disorder (OCPD): Perfectionism, preoccupation with order, associated with dopamine pathways and seen in Parkinson's disease patients.

Dissociative Disorders

• Dissociative Identity Disorder (DID): Presence of two or more distinct identities, often with amnesia for events experienced by other identities. Typically linked to severe childhood trauma.

• Diagnosis and Treatment: DID is controversial but can be distinguished from simulation using clinical interviews and brain imaging. Treatment involves symptom stabilization, trauma processing, and integration of identities.

Anxiety, Obsessive-Compulsive, and Depressive Disorders

Anxiety Disorders

Anxiety disorders involve excessive, irrational fear or nervousness, often interfering with daily life. They are among the most common psychological disorders.

• Generalized Anxiety Disorder (GAD): Persistent, elevated anxiety not tied to specific situations; associated with overactive amygdala and attentional networks.

• Panic Disorder: Sudden, intense panic attacks with physical symptoms; may lead to agoraphobia (avoidance of public places).

• Specific Phobias: Intense, irrational fear of specific objects or situations (e.g., animals, heights, blood). Influenced by genetics, learning, and evolutionary factors.

• Social Anxiety Disorder: Fear of social judgment or embarrassment, leading to avoidance of social situations.

Obsessive-Compulsive Disorder (OCD)

• Obsessions: Unwanted, persistent thoughts (e.g., contamination, doubt).

• Compulsions: Repetitive behaviors performed to reduce anxiety (e.g., checking, cleaning).

• Biological Basis: Involves orbitofrontal cortex, basal ganglia, thalamus, and other brain regions related to decision making and emotion regulation.

Mood Disorders

• Major Depression: Prolonged sadness, hopelessness, cognitive and physical symptoms, social withdrawal. Associated with pessimistic explanatory style and overactive amygdala.

• Bipolar Disorder: Alternating periods of depression and mania (elevated mood, impulsivity, risky behavior). Mania can be enjoyable but often leads to negative consequences.

• Genetic and Biological Factors: Twin studies show genetic predisposition. The diathesis-stress model explains how genetic vulnerability and environmental stressors interact.

• Neurotransmitters: Serotonin, dopamine, and norepinephrine are implicated. Antidepressants often target these systems.

• Sociocultural Influences: Poverty, neighborhood quality, social support, and social media can affect depression risk. The COVID-19 pandemic has increased rates of depression and anxiety.

Suicide

• Prevalence: Second leading cause of death among Canadian youth; higher rates among males and Indigenous communities.

• Risk Factors: Mood disorders, stressful life events, family history, substance abuse, social isolation.

• Warning Signs: Talking about dying, withdrawal, behavioral changes, giving away possessions.

• Prevention: Supportive communities, cultural reconnection, and access to mental health resources reduce risk.

Schizophrenia

Overview and Symptoms

Schizophrenia is a severe psychological disorder characterized by delusions, hallucinations, disorganized thinking, and impaired cognitive and social functioning. It affects about 0.4% to 0.8% of adults worldwide.

• Positive Symptoms: Hallucinations, delusions, disorganized behavior.

• Negative Symptoms: Flat affect, social withdrawal, lack of motivation, catatonia.

• Cognitive Symptoms: Impaired working memory, attention, and executive function.

Course and Phases

Phase	Key Features
Prodromal	Confusion, social withdrawal, loss of motivation
Active	Delusions, hallucinations, disorganized thoughts/behavior
Residual	Symptom reduction, continued withdrawal, concentration issues

Etiology (Causes)

• Genetic Factors: Risk increases with genetic relatedness. Concordance rates are highest in monozygotic twins (up to 49%). Over 100 genes are implicated.

• Neurobiological Factors: Enlarged ventricles, reduced brain volume (especially in frontal lobes, amygdala, hippocampus), dopamine overactivity (positive symptoms), and glutamate underactivity (negative symptoms).

• Neurodevelopmental Hypothesis: Disrupted brain development due to prenatal factors (maternal stress, malnutrition, infection) increases risk. Timing of exposure is critical, especially during the first trimester.

• Adolescent Brain Changes: Excessive synaptic pruning in adolescence may reduce prefrontal cortex efficiency, contributing to symptom onset.

• Environmental and Social Factors: Difficult births, head injuries, urban living, social defeat, high family emotional expressiveness, and cannabis use can increase risk, especially in genetically predisposed individuals.

Cultural Perspectives

• Symptom Interpretation: Cultural beliefs shape how symptoms are understood and treated (e.g., spiritual explanations in some cultures).

• Outcomes: Supportive and compassionate care, often found in traditional cultures, is associated with better long-term outcomes.

Summary Tables

Genetic Risk for Schizophrenia

Relationship	Risk (%)
General population	2
Monozygotic twins	49
Dizygotic twins	18
Offspring of two affected parents	46
Children	13
Siblings	9
Parents	7
Half siblings	7
Grandchildren	6
Nephews/Nieces	5
Uncles/Aunts	3
First cousins	3
Spouses	3

Key Terms and Concepts

• Maladaptive Behavior: Actions or thoughts that harm the individual or others.

• DSM-5-TR: The current standard for diagnosing psychological disorders.

• Diathesis-Stress Model: $\text{Disorder risk} = f(\text{genetic vulnerability}, \text{environmental stress})$

• Positive vs. Negative Symptoms: Positive = excesses/distortions (e.g., hallucinations); Negative = deficits (e.g., flat affect).

Examples and Applications

• Case Study: John Nash (schizophrenia) – illustrates challenges and potential for recovery.

• Public Figures: Athletes and celebrities discussing mental health reduce stigma and encourage help-seeking.

• Legal Cases: Mental disorder defence in court relies on psychological assessment of the defendant's ability to distinguish right from wrong.

Additional info: The notes above expand on brief points with academic context, definitions, and examples to ensure a comprehensive, self-contained study guide suitable for exam preparation.