Getting Started
Psychological disorders represent patterns of thoughts, feelings, or behaviors that are deviant, distressful, and dysfunctional, often causing significant impairment in a person's life. To study and treat these conditions, psychologists classify them into distinct categories based on shared symptoms. This chapter provides an overview of the major categories of psychological disorders, exploring their defining characteristics and the diverse factors—from biology to environment—that may contribute to their development.
What You Should Be Able to Do
After reviewing this material, you should be able to:
Describe the core symptoms for major categories of psychological disorders.
Compare and contrast the characteristics of different disorders, such as depressive versus bipolar disorders.
Explain the possible causes of selected disorders using multiple psychological perspectives.
Differentiate between positive and negative symptoms, particularly in the context of schizophrenia.
Key Developments & Analysis
Understanding the causes of psychological disorders requires examining them through multiple theoretical lenses. Each perspective offers a different explanation for why these complex conditions arise, and a comprehensive view often integrates ideas from all of them.
| Perspective | Core Claim | Mechanism (how) | One Example |
|---|---|---|---|
| Biological/Genetic | Disorders stem from physiological factors like brain chemistry, structure, and genetic predispositions. | Imbalances in neurotransmitters, inherited vulnerabilities, or brain abnormalities contribute to symptoms. | Schizophrenia may be linked to an excess of the neurotransmitter dopamine, a concept known as the dopamine hypothesis. |
| Cognitive | Disorders are caused or maintained by maladaptive thinking patterns, such as irrational beliefs and distorted perceptions. | Negative thought cycles, faulty interpretations of events, and pessimistic explanatory styles create and maintain distress. | Depressive disorders can be rooted in persistent negative thoughts about oneself, the world, and the future. |
| Behavioral/Learning | Disorders are learned behaviors acquired through conditioning and observation. | A phobia might develop through classical conditioning (associating an object with fear) and be maintained by operant conditioning (avoidance). | Specific phobias can be explained by learned associations between a particular object or situation and a fear response. |
| Sociocultural/Environmental | Disorders are influenced by social and cultural contexts, including societal expectations, trauma, and stress. | Cultural norms define what is "deviant," and experiences like trauma or significant life stressors can trigger or worsen disorders. | Post-traumatic stress disorder is, by definition, caused by exposure to a traumatic event, a powerful environmental stressor. |
Data & Organization Tools
The following matrix organizes the major categories of psychological disorders by their core features and provides key examples for each.
| Category | Core Characteristic(s) | Example(s) |
|---|---|---|
| Neurodevelopmental | Onset during the developmental period; impairs personal, social, or academic functioning. | Attention-Deficit/Hyperactivity Disorder (ADHD), Autism Spectrum Disorder |
| Schizophrenia Spectrum | Characterized by delusions, hallucinations, disorganized thinking/behavior, and/or negative symptoms. | Schizophrenia |
| Depressive | Persistent sad, empty, or irritable mood, accompanied by somatic and cognitive changes. | Major Depressive Disorder |
| Bipolar and Related | Alternating periods of mania (elevated, expansive, or irritable mood) and depression. | Bipolar Disorder |
| Anxiety | Excessive and persistent fear, anxiety, and related behavioral disturbances. | Specific Phobia, Generalized Anxiety Disorder (GAD), Panic Disorder, Agoraphobia |
| Obsessive-Compulsive | Presence of obsessions (intrusive thoughts) and/or compulsions (repetitive behaviors). | Obsessive-Compulsive Disorder (OCD), Hoarding Disorder |
| Dissociative | Disruption of and/or discontinuity in the normal integration of consciousness, memory, or identity. | Dissociative Amnesia, Dissociative Identity Disorder (DID) |
| Trauma & Stressor-Related | Caused by exposure to a traumatic or stressful event, leading to subsequent distress. | Post-Traumatic Stress Disorder (PTSD) |
| Feeding and Eating | A persistent disturbance of eating or eating-related behavior that impairs health or functioning. | Anorexia Nervosa, Bulimia Nervosa |
| Personality | An enduring, pervasive, and inflexible pattern of experience and behavior that deviates from one's culture. | Antisocial Personality Disorder, Borderline Personality Disorder, Avoidant Personality Disorder |
Evidence Bank
Positive Symptoms: In schizophrenia, the presence of inappropriate behaviors. Examples include delusions (false beliefs) and hallucinations (false perceptions).
Negative Symptoms: In schizophrenia, the absence of appropriate behaviors. An example is flat affect, a state of diminished emotional expression.
Dopamine Hypothesis: A biological theory suggesting that schizophrenia is caused by an excess of dopamine activity in the brain.
Mania: A key feature of bipolar disorders, defined as a hyperactive, wildly optimistic state in which dangerously poor judgment is common.
Obsessions: Unwanted, repetitive, and intrusive thoughts that cause significant anxiety or distress.
Compulsions: Repetitive behaviors or mental acts that an individual feels driven to perform in response to an obsession, aimed at reducing anxiety.
Catatonia: A state of disorganized motor behavior, often seen in schizophrenia, that can manifest as immobility or excessive, purposeless movement.
Personality Disorder Clusters: The three groupings of personality disorders based on shared characteristics: Cluster A (odd, eccentric), Cluster B (dramatic, emotional, erratic), and Cluster C (anxious, fearful).
Skill Snapshots
Mechanism Pairs
Cause → Effect: Exposure to a severe traumatic event → Development of PTSD symptoms like intrusive memories and avoidance.
Cause → Effect: An imbalance of neurotransmitters (biological cause) → The sad, empty mood characteristic of a major depressive episode.
Cause → Effect: A learned association between a specific object (e.g., a spider) and fear → The intense, irrational fear seen in a specific phobia.
Perspective Contrasts
Depression: A biological perspective points to genetic predispositions and neurotransmitter imbalances, while a cognitive perspective focuses on persistent negative thought patterns and beliefs.
Anxiety: A behavioral perspective explains phobias as learned associations from past experiences, while a biological perspective points to an individual's genetic vulnerability to anxiety.
Eating Disorders: A sociocultural perspective emphasizes cultural pressures for thinness, while a biological perspective investigates genetic links and hormonal imbalances that may contribute to the disorder.
Change Track: Development of Social Anxiety Disorder
Baseline: An individual has a genetic predisposition for anxiety.
Change 1: They experience a stressful social event, such as being publicly embarrassed, which creates a learned association (social situations = danger).
Change 2: They begin to avoid social situations. This avoidance reduces their immediate anxiety, which negatively reinforces the avoidant behavior.
Persistence: The pattern of fear and avoidance becomes an enduring and inflexible part of their behavior, causing significant impairment and meeting the criteria for Social Anxiety Disorder.
Common Misconceptions & Clarifications
Misconception: Schizophrenia means having a "split personality."
- Clarification: Schizophrenia involves a "split from reality" (psychosis), characterized by symptoms like delusions and hallucinations. A "split personality" more accurately, though simplistically, describes Dissociative Identity Disorder (DID).
Misconception: Negative symptoms are just "bad" or severe symptoms.
- Clarification: In the context of schizophrenia, negative symptoms refer to the absence of a typical behavior (e.g., lack of emotional expression). Positive symptoms refer to the presence of an atypical behavior (e.g., hallucinations).
Misconception: Bipolar disorder is just extreme moodiness.
- Clarification: Bipolar disorder is defined by distinct, alternating periods of depression and mania—a state of elevated energy and often reckless behavior that is far beyond a typical mood swing and causes significant functional impairment.
Misconception: A personality disorder is just a person's difficult personality.
- Clarification: Personality disorders are not just personality quirks. They are enduring, pervasive, and inflexible patterns of behavior that are highly deviant from cultural norms and cause significant distress or impairment in social, occupational, or other important areas of functioning.
One-Paragraph Summary
Psychological disorders are classified into categories based on shared symptoms that disrupt an individual's thoughts, emotions, and behaviors. This framework allows for a systematic approach to understanding conditions ranging from neurodevelopmental disorders that begin in childhood to enduring personality disorders. The causes of these disorders are multifaceted and are best explained by integrating multiple perspectives; biological factors like genetics and neurotransmitters, cognitive patterns like maladaptive thoughts, behavioral learning, and sociocultural influences like trauma all play a role. Key diagnostic concepts, such as the distinction between positive and negative symptoms in schizophrenia or obsessions and compulsions in OCD, are critical for accurate description. Ultimately, this system of classification provides a vital language for clinicians and researchers to diagnose, study, and treat psychological distress and impairment.