Psychological Disorders: Features, Prevalence, and Etiology

Obsessive-Compulsive Disorder (OCD): Characterized by obsessions (intrusive, persistent, and unwanted thoughts) and compulsions (ritualistic behaviors performed to minimize distress). Common obsessions include contamination, doubts, and symmetry. Prevalence is approximately $2.3\%$ of the U.S. population.
Body Dysmorphic Disorder: Preoccupation with perceived physical flaws that are nonexistent or minor, pushing individuals toward repetitive acts like excessive mirror checking. Lifetime prevalence is $2.4\%$
Hoarding Disorder: Chronic difficulty parting with possessions regardless of value, leading to extreme clutter that makes living areas unusable.
Etiology: OCD has a moderate genetic component; concordance rates are $57\%$ for identical twins and $22\%$ for fraternal twins. The orbitofrontal cortex, part of the OCD circuit, shows hyperactivity during symptom provocation.

Posttraumatic Stress Disorder (PTSD): Triggered by exposure to extreme trauma (actual/threatened death, serious injury, or sexual violence). Symptoms include flashbacks, avoidance, negative emotional states, and exaggerated startle response for at least one month.
Prevalence: Civilian lifetime prevalence is between $3.6\%$ and $8.0\%$ , while veteran rates range from $7.7\%$ to $13.4\%$
Risk Factors: Factors include trauma severity, lack of social support, childhood adversity, and the presence of one or two short versions of a gene regulating serotonin.
Prolonged Grief Disorder (PGD): A new DSM-5-TR diagnosis for adults experiencing debilitating yearning for a deceased person for at least $12$ months ( $6$ months for children).

Major Depressive Disorder (MDD): Requires depressed mood and loss of interest in usual activities for at least $2$ weeks. It affects approximately $6.6\%$ of the U.S. population annually; lifetime prevalence is $16.9\%$
Subtypes: Includes seasonal pattern ("winter blues"), peripartum onset (postpartum depression), and Persistent Depressive Disorder (depressed mood lasting for at least $2$ years).
Bipolar Disorder: Characterized by mood vacillation between depression and mania. Mania involves euphoric/irritable mood, flight of ideas, and grandiosity lasting at least one week. Lifetime prevalence is $1\%$
Biological Factors: Linked to imbalances in serotonin, norepinephrine, and dopamine. Depressed individuals show elevated amygdala activity and decreased prefrontal cortex (PFC) activation. High cortisol levels are a known risk factor.
Cognitive Theories: Includes Beck's theory of depressive schemas and Hopelessness theory, which emphasizes stable and global attributions for negative events.

Suicide: The $10\text{th}$ leading cause of death in the U.S. in 2010. Males are $4 \times$ more likely to die by suicide than females. Risk is highest among those with mood or substance use disorders.
Nonsuicidal Self-Injury: Deliberate harm to the body to cope with emotional pain. It is a risk factor for suicide and often results in social stigmatization.
Neurobiology: Low levels of serotonin are linked to violence and impulsivity in suicidal behavior.

Major Symptoms: Hallucinations (mostly auditory), delusions (paranoid, grandiose, somatic), disorganized thinking (tangentiality), disorganized motor behavior (catatonia), and negative symptoms (avolition, alogia, asociality, anhedonia).
Etiology: Risk is $6 \times$ higher with a parent having the disorder. The dopamine hypothesis suggests an overabundance of dopamine in the limbic system causes positive symptoms.
Structural Findings: Imaging shows enlarged ventricles and reduced gray matter in the frontal lobes.
Risk Factors: Genetic vulnerability combined with environmental stress (diathesis-stress), obstetric complications, and marijuana use during adolescence.

Dissociative Amnesia: Inability to recall important personal information after trauma. May include dissociative fugue, where an individual wanders away and experiences identity confusion.
Depersonalization/Derealization Disorder: Persistent feelings of detachment from the self or world (feeling like one is in a fog/dream).
Dissociative Identity Disorder (DID): Presence of two or more distinct personality states and memory gaps. Often associated with severe childhood trauma.

Attention Deficit/Hyperactivity Disorder (ADHD): Pattern of inattention and/or hyperactivity-impulsivity. Heritability is approximately $71\%$ for inattention. Studies show lower dopamine activity in motivation/reward brain regions.
Autism Spectrum Disorder: Deficits in social interaction and communication, along with repetitive patterns of behavior. Prevalence is $1$ in $59$ children. Identical twin concordance is $60\%-90\%$
Vaccine Myths: Extensive research, including a study of $256$ children, confirms there is no link between the MMR vaccine or immunogen quantity and autism.

Cluster A (Odd/Eccentric): Paranoid, Schizoid, Schizotypal.
Cluster B (Impulsive/Erratic): Antisocial, Histrionic, Narcissistic, Borderline.
Cluster C (Anxious/Fearful): Avoidant, Dependent, Obsessive-Compulsive.
Borderline Personality Disorder: Instability in mood, self-image, and relationships; high impulsivity. Prevalence is roughly $1.4\%$
Antisocial Personality Disorder: Disregard for others' rights, lack of remorse, and impulsivity. Affects $3.6\%$ of the population, predominantly males at a $3:1$ ratio.

Question (Insanity Plea): What happened to Cody Metzker-Madsen after he claimed he was fighting goblins when he killed a child?
Response: He was found not guilty by reason of insanity. He was placed in a psychiatric facility and will remain there until judged no longer dangerous; such individuals are often confined as long as or longer than those in prison.