Psychological disorders

Approaches in understanding psychological disorders

Biomedical vs. biopsychosocial approaches

• Health psychology examines how health is influenced by biological, psychological, and sociocultural factors, an integrated view often called the biopsychosocial model.
• Specialists in health psychology aim to help individuals improve well-being through public policy, education, intervention, and research. They might investigate how genetics, behavioral patterns, relationships, and psychological stress together affect health, or develop methods that encourage positive behavior changes to counteract poor health outcomes.

Classifying psychological disorders

• A psychological disorder or mental disorder can be described as a syndrome showing significant disruption in cognition, emotion regulation, or behavior, stemming from dysfunction in psychological, biological, or developmental processes.
• This disruption typically causes substantial distress or difficulty in everyday life (e.g., social or occupational settings). The field of psychopathology involves the study of these disorders—exploring symptoms, causes (etiology), and treatments—as well as how disorders display in individuals.

Since no single, universal definition applies to every situation, one useful perspective is the concept of harmful dysfunction, which views mental processes (like cognition, perception, learning) as evolutionarily shaped internal systems. A dysfunction arises when these processes fail to operate normally. But a dysfunction is only classified as a disorder if it causes harm, measured by cultural standards or by notable distress or impairment in daily life.

In the United States, many practitioners use the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) to categorize mental health conditions, including detailed descriptions of each disorder, diagnostic criteria, prevalence data, and risk factors. The DSM-5 also addresses comorbidity, meaning when two or more disorders occur together.

Rates of psychological disorders

Lifetime prevalence rates reveal how often certain disorders appear among adults in the United States, based on a large, nationally representative sample. Additionally, many disorders, such as substance use disorders, frequently occur alongside other forms of mental illness.

Types of psychological disorders

Anxiety

• Defined by excessive and persistent fear or anxiety and related disruptions in behavior, anxiety disorders include conditions like social anxiety disorder, panic disorder, and generalized anxiety disorder. Together, they are among the most frequently occurring mental health issues and are often comorbid with other disorders.
  • Social anxiety disorder: Intense fear of negative evaluation in social situations leading to avoidance behaviors.
  • Panic disorder: Recurrent, unexpected panic attacks (sudden bursts of extreme fear, including intense fight-or-flight symptoms) paired with ongoing worries about additional attacks or behavioral changes to prevent them.
  • Generalized anxiety disorder: Chronic and excessive worry about mundane matters, accompanied by restlessness, irritability, or difficulties with sleep and concentration.

Obsessive-compulsive disorder (OCD)

• Marked by intrusive and unpleasant obsessions (persistent, unwanted thoughts or urges) and/or compulsions (repetitive behaviors or mental acts aimed at reducing anxiety). Individuals with OCD realize their thoughts may be illogical, yet find them difficult to ignore.

Trauma- and stressor-related disorders

• Exposure to extremely stressful or traumatic events can lead to disorders like posttraumatic stress disorder (PTSD).
• Symptoms include intrusive memories, avoidance of related cues, negative emotional states, and heightened startle responses, persisting for at least one month.

Somatic symptom and related disorders

• Involve physical symptoms that cause significant distress in thoughts, feelings, and behaviors, but which cannot be explained by other medical or psychological conditions. Examples include hypochondriasis, pain disorder, and conversion disorder.

Bipolar and related disorders

• Characterized by swings in mood from depression to mania. A manic episode refers to a distinct period of abnormally elevated or irritable mood alongside increased activity or energy. Depression may also be present but is not necessary for a bipolar disorder diagnosis.

Depressive disorders

• Encompass conditions where depression is primary. Major depressive disorder involves pervasive sadness or loss of interest in usual activities for at least two weeks, often with changes in appetite, sleep, and cognitive function. Subtypes include seasonal pattern (i.e. winter blues) and peripartum or postpartum (during or after pregnancy) onset.

Schizophrenia

• A psychotic disorder marked by extreme disruptions in thought, perception, emotion, and behavior, including hallucinations, delusions, and disorganized actions. People with schizophrenia often face challenges in everyday functioning.

Dissociative disorders

• Involve a detachment or split from one’s core sense of self, impacting memory and identity. They include dissociative amnesia, depersonalization/derealization disorder, and dissociative identity disorder (in which two or more distinct personality states emerge).

Personality disorders

• Entail pervasive and enduring personality styles that deviate significantly from cultural norms, causing distress and impairing social relationships. The DSM-5 organizes them into:
  • Cluster A (odd or eccentric traits), i.e. Paranoid personality disorder, Schizoid personality disorder
  • Cluster B (dramatic, emotional, or erratic traits), i.e. Antisocial, Borderline, Histrionic and Narcissistic personality disorders
  • Cluster C (nervous or fearful traits), i.e. Avoidant, Dependent and Obsessive-compulsive personality disorders

Biological bases of nervous system disorders

Schizophrenia

• There is strong evidence of a genetic component. Excess dopamine activity has been linked to schizophrenia, and medications blocking dopamine or serotonin receptors can ease symptoms. Structural brain differences—like enlarged ventricles and reduced gray matter—are also found in many affected individuals.

Depression

• Mood disorders (including major depressive disorder and bipolar conditions) often run in families, suggesting genetic and biological influences. Brain regions regulating emotional processing and response (such as the amygdala and prefrontal cortex) show abnormal activity. Low levels or imbalances in norepinephrine and serotonin can contribute to depression.

Alzheimer’s disease

• Characterized by the buildup of amyloid deposits and tau protein, which damages neurons and produces plaques. This leads to severe memory impairment. Genetic susceptibility and factors like Down syndrome, type 2 diabetes, hypertension, repeated concussions, and chronic inflammation can raise the risk of Alzheimer’s.

Parkinson’s disease

• Primarily affects dopamine-producing neurons in the substantia nigra, due to deposits of alpha synuclein. Common signs include rigidity, resting tremors, abnormal gait [e.g., shuffling, freezing, festination (short, rapid steps with a forward lean)], slowed movements, and emotional or cognitive changes. Although often idiopathic, certain neurotoxins can cause Parkinson’s. Dopamine agonists are a treatment option.

Stem cell-based therapy for CNS regeneration

• Neural stem cells have the ability to create new brain cells (including neurons, astrocytes, and oligodendrocytes), potentially restoring function lost in neurodegenerative diseases such as Parkinson’s disease or ALS (Lou Gehrig’s disease).