Clinical Psychology.

OpeningWhat clinical psychology is.

The discipline that takes mental suffering as its subject and tries, with limited tools, to relieve it.

Modern clinical psychology dates from roughly 1950: the post-war proliferation of psychiatric care, the introduction of chlorpromazine (1952) and the first effective antidepressants (iproniazid, 1957; imipramine, 1958), the publication of the first DSM (1952), and the gradual professionalisation of doctoral-level psychotherapy.

The discipline now sits at the intersection of three projects: diagnosis (the DSM and ICD systems), treatment (psychotherapies of various kinds, plus the pharmacological interface), and research (the evidence base for what works and for whom). Each is contested. This deck covers the major disorders, the dominant therapy modalities, and the philosophical critiques the field has carried since its beginning.

Chapter IHow we got here.

The 19th-century asylums (Pinel in Paris, the York Retreat, the great American state hospitals) were, on paper, a humanitarian advance over the older confinement and exorcism traditions. In practice they became warehouses. By 1955, US state hospital populations peaked at 559,000 beds.

The pharmacological turn started in 1952. Chlorpromazine was the first antipsychotic; lithium for bipolar disorder was discovered by John Cade (1949) and entered Western practice in the late 1960s; the tricyclics and MAOIs arrived in 1957–58. The drugs made deinstitutionalisation possible (Kennedy's 1963 Community Mental Health Act).

The 1980 publication of DSM-III (Robert Spitzer, principal architect) revolutionised psychiatric classification by replacing psychoanalytic categories with operational, behaviourally-defined criteria. Whatever its philosophical limits, this gave psychiatric research an ability to compare across studies it had not previously had.

Chapter IIThe DSM and ICD.

The Diagnostic and Statistical Manual of Mental Disorders, published by the American Psychiatric Association, is the primary classification system in North America. The International Classification of Diseases (ICD), now ICD-11 (WHO, 2022), is the global system. They mostly agree.

DSM-III (1980) was the watershed. It introduced operational criteria: disorders defined by lists of symptoms (must have 5 of 9 symptoms for at least 2 weeks for major depression, etc.) rather than by inferred psychodynamic causes. This made research replicable and insurance billable. It also entrenched a categorical model — you have the disorder or you don't — that the field has since walked back.

The medical model and its limits

DSM disorders are descriptions, not explanations. Two patients with the same DSM diagnosis can have different underlying biology, different histories, different treatment responses. The RDoC (Research Domain Criteria) framework, proposed by NIMH in 2010, was an attempt to ground research in dimensional biological constructs rather than DSM categories. It has had mixed uptake.

Chapter IIIMajor depressive disorder.

Defined by the DSM-5 as ≥5 of 9 symptoms for ≥2 weeks: depressed mood; anhedonia; weight/appetite change; insomnia or hypersomnia; psychomotor change; fatigue; worthlessness or guilt; concentration impairment; suicidal ideation. At least one symptom must be depressed mood or anhedonia.

Course

About half of first episodes recur; about a third have a chronic course. Untreated episodes typically last 6–9 months. The single best predictor of future episodes is past episodes.

Treatments that work

SSRIs (fluoxetine, sertraline) — moderate effect sizes; full effect at 4–6 weeks. SNRIs (venlafaxine, duloxetine). CBT — comparable effect sizes to medication for mild-moderate depression; better long-term durability. Behavioural activation — empirically strong, often underused. Interpersonal therapy. ECT — most effective treatment for severe and refractory depression. Ketamine and the FDA-approved esketamine (Spravato, 2019) — rapid effect for treatment-resistant cases.

Chapter IVBipolar disorder.

Lifetime prevalence ~1% for bipolar I; another 1–2% for bipolar II. High heritability (~60–80% — among the most heritable psychiatric disorders). Average age of onset around 18–22. Suicide risk is roughly 15× the general population.

Diagnostic criteria for mania

≥1 week of elevated/expansive/irritable mood plus ≥3 of: inflated self-esteem; decreased sleep need; pressured speech; racing thoughts; distractibility; increased goal-directed activity; impulsive risky behaviour. The DSM-5 added a "with mixed features" specifier for mixed states.

Treatment

Lithium remains the gold standard for prevention; reduces suicide risk specifically. Anticonvulsants (valproate, lamotrigine — the latter especially for bipolar depression). Atypical antipsychotics (quetiapine, lurasidone, olanzapine). Antidepressants alone are contraindicated — they can precipitate mania.

Kay Redfield Jamison's An Unquiet Mind (1995) is the canonical first-person account; her textbook Manic-Depressive Illness (with Goodwin) is the standard clinical reference.

Chapter VThe anxiety family.

Generalised Anxiety Disorder (GAD). Excessive anxiety and worry occurring more days than not for ≥6 months, plus physical symptoms (restlessness, fatigue, concentration difficulty, irritability, muscle tension, sleep disturbance).

Panic Disorder. Recurrent unexpected panic attacks plus persistent concern about further attacks. Lifetime prevalence ~5%.

Social Anxiety Disorder. Marked fear of social or performance situations. Lifetime prevalence ~12%.

Specific Phobia. Marked fear of a circumscribed object/situation. Most prevalent.

Obsessive-Compulsive Disorder (OCD). Reclassified out of "Anxiety Disorders" in DSM-5 into its own category. Obsessions (intrusive unwanted thoughts) and compulsions (repetitive behaviours done to neutralise them). Effective treatments: SSRIs at higher doses than for depression; Exposure and Response Prevention (ERP) — the evidence-based behavioural treatment.

Treatment

SSRIs and SNRIs for most anxiety disorders. Cognitive-Behavioural Therapy (CBT) with exposure components — strong evidence base across the family. Benzodiazepines provide rapid symptom relief but carry dependence risk; long-term use is generally discouraged.

Chapter VIPost-Traumatic Stress Disorder.

The DSM-5 criteria require exposure to actual or threatened death, serious injury, or sexual violation — directly, witnessed, learned about, or via repeated work-related exposure. Plus symptoms across four clusters: intrusion (flashbacks, nightmares); avoidance (of trauma reminders); negative cognitions and mood; hyperarousal.

Lifetime prevalence ~6–9% (US). Most people exposed to traumatic events do not develop PTSD; the conditional probability depends on event type (combat ~30%, sexual assault ~50%, motor vehicle accident ~10%) and pre-existing risk factors.

Treatments with strong evidence

Trauma-focused CBT (especially Cognitive Processing Therapy, Patricia Resick) and Prolonged Exposure (Edna Foa). EMDR (Francine Shapiro, 1989) — controversial mechanism, but meta-analytic evidence for efficacy. SSRIs as adjunct. MDMA-assisted psychotherapy in clinical trials (the FDA rejected approval in August 2024, but MAPS continues research).

Complex PTSD (cPTSD) — formally added to ICD-11 in 2018 — captures the consequences of prolonged or repeated trauma, often early in life. Includes core PTSD symptoms plus disturbances in self-organisation: emotional dysregulation, negative self-concept, interpersonal difficulties.

Chapter VIISchizophrenia.

Lifetime prevalence ~0.7% (much more uniform across cultures than other psychiatric disorders). High heritability (~80%). Modal onset in late teens/early 20s for men, mid-20s/early 30s for women.

The DSM-5 requires ≥2 of 5 symptoms for ≥1 month, with at least one being a positive symptom (hallucinations, delusions, or disorganised speech). Plus ≥6 months of disturbance overall and significant functional decline.

Course

The "rule of thirds" historically: a third recover substantially, a third have moderate ongoing symptoms, a third have chronic disabling illness. Modern figures are more optimistic with treatment, though the disorder remains the most severe psychiatric condition by aggregate disability.

Treatment

Antipsychotics — first-generation (chlorpromazine, haloperidol) primarily block D2 receptors and have movement-disorder side effects (extrapyramidal symptoms, tardive dyskinesia). Second-generation atypicals (clozapine, olanzapine, risperidone, aripiprazole) have a different side-effect profile (metabolic syndrome). Clozapine remains the most effective antipsychotic but requires blood monitoring (agranulocytosis risk). Long-acting injectables address the major treatment-adherence problem.

Chapter VIIIPersonality disorders.

The DSM-5 retained the categorical 10-disorder model with three clusters; in Section III it offered an alternative dimensional model (the AMPD) which may become primary in DSM-6. The ICD-11 has fully shifted to a dimensional model.

Borderline Personality Disorder

The most-researched personality disorder. Characterised by unstable affect, identity, and relationships; impulsivity; recurrent suicidal behaviour or self-injury. Lifetime prevalence ~1.6%. The disorder was historically considered untreatable. Marsha Linehan's Dialectical Behaviour Therapy (DBT), developed in the 1980s, is now the standard evidence-based treatment. Linehan herself disclosed in 2011 that she had received a borderline diagnosis as an adolescent.

Other PD treatments: Mentalization-Based Treatment (MBT) for borderline (Anthony Bateman, Peter Fonagy); Schema Therapy (Jeffrey Young) for personality pathology more broadly.

Antisocial Personality Disorder

Pervasive disregard for others' rights since age 15, with conduct disorder before age 15. The diagnosis overlaps but is not equivalent to psychopathy as measured by the Hare PCL-R.

Chapter IXEating disorders.

Anorexia nervosa. Restriction of food intake leading to significantly low body weight, intense fear of gaining weight, disturbance in self-perception of body. Subtypes: restricting; binge-eating/purging.

Bulimia nervosa. Recurrent binge-eating episodes plus inappropriate compensatory behaviours (vomiting, laxatives, fasting, excessive exercise). At least once per week for three months.

Binge Eating Disorder (BED). Recurrent binge-eating without compensatory behaviour. Added as a formal diagnosis in DSM-5. The most prevalent of the three.

ARFID (Avoidant/Restrictive Food Intake Disorder). Added in DSM-5; restriction of intake without body-image disturbance — often associated with autism, sensory issues, or specific phobias of food.

Treatment

Family-Based Treatment (FBT, Maudsley approach) for adolescent anorexia. CBT-E (enhanced CBT, Christopher Fairburn) for bulimia and BED. Weight restoration is the necessary first step in anorexia treatment; SSRIs are not effective for the core disorder. The clinical literature is increasingly attentive to atypical presentations and to higher-weight patients with eating-disorder pathology.

Chapter XNeurodevelopmental disorders.

Autism Spectrum Disorder (ASD). Persistent deficits in social communication and interaction across contexts, plus restricted, repetitive patterns of behaviour, interests, or activities. The DSM-5 collapsed the previous subdiagnoses (autistic disorder, Asperger's, PDD-NOS) into a single dimensional spectrum. Estimated US prevalence has risen from ~0.4% in 2000 to ~2.7% in 2023; how much is true increase vs. better detection vs. diagnostic broadening is debated.

ADHD. Inattentive, hyperactive-impulsive, or combined presentation, with onset before age 12. Adult ADHD (formally added in DSM-5) is one of the fastest-growing diagnoses. Effective treatments: stimulants (methylphenidate, amphetamines) — among the most effective psychiatric treatments by effect size; non-stimulants (atomoxetine, guanfacine); behavioural interventions for children.

Intellectual Disability. Replaced the older "mental retardation" label. Defined by both intellectual functioning (IQ approximately 2 SD below mean) and adaptive functioning. The DSM-5 emphasises adaptive over IQ criteria.

Chapter XIAddiction.

The chronic-disease model (Alan Leshner, 1997) frames substance-use disorders as brain disorders involving conditioned learning, reward dysregulation, and impaired executive function. Critics (Stanton Peele, Marc Lewis) argue this model overstates the role of brain pathology and understates the role of environment, choice, and meaning.

Effective treatments

Opioid use disorder: medication-assisted treatment (methadone, buprenorphine, naltrexone) — the strongest evidence base. Alcohol use disorder: naltrexone, acamprosate; twelve-step facilitation; cognitive-behavioural relapse prevention. Tobacco use disorder: nicotine replacement, varenicline, bupropion. Stimulant use disorders: contingency management has the strongest evidence (despite low uptake in clinical practice). For most substances: a combination of medication, behavioural therapy, and social support outperforms any one alone.

The opioid epidemic in the US (~80,000 overdose deaths annually) has reshaped the field's policy interface; harm-reduction approaches (naloxone distribution, supervised consumption sites) have moved from fringe to mainstream practice.

Chapter XIICognitive-Behavioural Therapy.

The most-researched psychotherapy. Cognitive therapy (Beck) and Rational-Emotive Behaviour Therapy (Albert Ellis, 1955) merged with behaviour therapy into the unified CBT framework that dominates evidence-based practice.

The basic model: thoughts, feelings, and behaviours influence each other. Distorted or unhelpful thoughts can be identified, examined, and modified through structured techniques (cognitive restructuring, behavioural experiments, behavioural activation, exposure). The therapy is typically 12–20 sessions, time-limited, structured, and homework-heavy.

Evidence

Strong meta-analytic evidence for CBT in: depression, anxiety disorders, OCD, PTSD, eating disorders, insomnia, chronic pain. Effect sizes typically d = 0.5–0.9 vs waitlist. Comparative-effectiveness studies (e.g., Cuijpers et al. meta-analyses) generally find CBT comparable to other bona fide psychotherapies; the Dodo bird verdict (everything wins, all therapies are roughly equivalent in efficacy) is partly true, partly contested.

The criticism: CBT can be technical and depersonalising; doesn't address some chronic interpersonal patterns; the durability of effects post-termination varies.

Chapter XIIIPsychodynamic therapy.

The contemporary descendant of psychoanalysis. Less couch, more chair; less interpretation of unconscious wishes, more attention to relational patterns. The core technique: examining how the client relates to the therapist (transference) for what it reveals about other relationships.

Variants

Mentalization-Based Therapy (MBT) — Peter Fonagy and Anthony Bateman, originally for borderline personality disorder. Targets the capacity to think about thoughts and feelings (one's own and others').

Transference-Focused Psychotherapy (TFP) — Otto Kernberg's structured psychodynamic approach for severe personality pathology.

Short-Term Dynamic Psychotherapy (STDP) — Habib Davanloo's intensive variant.

Attachment-based therapy — drawing on Bowlby/Ainsworth.

Empirical status

The evidence base for short-term psychodynamic therapy is more substantial than commonly believed. Long-term psychoanalysis remains harder to evaluate empirically and harder to fund.

Chapter XIVThe third wave.

Three modalities anchor the contemporary third wave.

Acceptance and Commitment Therapy (ACT) — Steven Hayes. Six core processes: acceptance, cognitive defusion, present-moment awareness, self-as-context, values, committed action. The treatment shifts from changing thoughts to changing the relationship to thoughts. Strong evidence base across multiple disorders.

Dialectical Behaviour Therapy (DBT) — Marsha Linehan. Originally for chronically suicidal individuals with borderline personality disorder. Standard DBT involves individual therapy, group skills training (mindfulness, distress tolerance, emotion regulation, interpersonal effectiveness), phone coaching, and a therapist consultation team. The most-researched treatment for borderline.

Mindfulness-Based Cognitive Therapy (MBCT) — Segal, Williams, Teasdale. Eight-week group programme combining mindfulness practice with cognitive therapy elements; specifically validated for prevention of depressive relapse.

Adjacent: Compassion-Focused Therapy (Paul Gilbert); Emotion-Focused Therapy (Leslie Greenberg).

Chapter XVThe pharmacotherapy interface.

Major drug classes used in psychiatric practice:

SSRIs (fluoxetine, sertraline, escitalopram, paroxetine). First-line for depression and most anxiety disorders. Modest effect sizes; meta-analyses (Kirsch 2008; Cipriani 2018) suggest the average benefit over placebo is small but real, with greater benefit at more severe baseline.

SNRIs (venlafaxine, duloxetine). Similar to SSRIs; sometimes better for chronic pain comorbidity.

Antipsychotics. First-generation: D2-blocking, movement side effects. Second-generation atypicals: broader receptor profiles, metabolic side effects. Clozapine remains uniquely effective for treatment-resistant schizophrenia.

Mood stabilizers. Lithium for bipolar I; valproate, lamotrigine, carbamazepine.

Anxiolytics. Benzodiazepines (diazepam, alprazolam, clonazepam): rapid effect, dependence risk, generally not for chronic use. Buspirone: slower onset, lower dependence.

The relationship between psychotherapy and pharmacotherapy is integrative for most disorders. Combined treatment outperforms either alone for depression, anxiety, and most chronic conditions.

Chapter XVIThe psychedelic re-entry.

Psychedelic-assisted psychotherapy is the most-watched development in psychiatric treatment of the 2020s. Three substances are in late-stage clinical trials: psilocybin (the active compound in psilocybin mushrooms), MDMA (3,4-methylenedioxymethamphetamine, "ecstasy"), and ketamine (already FDA-approved as esketamine, Spravato, in 2019 for treatment-resistant depression).

The proposed mechanism: a 6–8 hour psychedelic experience under therapist supervision produces a shift in perspective that opens the patient to therapeutic processing of trauma or depressive material. Multiple sessions are typically combined with conventional therapy.

The MAPS phase-3 trials of MDMA-assisted therapy for PTSD reported large effect sizes (d ≈ 0.9) and high remission rates (67% of MDMA-group participants no longer met PTSD criteria at 18-week follow-up). The FDA's August 2024 rejection cited concerns about trial design (functional unblinding), data integrity, and reports of safety issues.

The next 3–5 years will determine whether psychedelics enter standard clinical practice or whether the regulatory and methodological obstacles are larger than enthusiasts assumed.

Chapter XVIIThe antipsychiatry tradition.

Thomas Szasz's The Myth of Mental Illness (1961) argued that "mental illness" was a category mistake — psychiatric disorders are not biological diseases but problems in living that have been medicalised for social-control purposes. Michel Foucault's Madness and Civilization (1961) traced the history of how the West confined the mad. R. D. Laing's The Divided Self (1960) argued that schizophrenia was an intelligible response to an impossible family situation.

The critique has continued. Mad in America (Robert Whitaker's 2010 book and the journal of that name) argues that psychiatric medications produce iatrogenic harm and worsen long-term outcomes. The Critical Psychiatry Network (UK). Joanna Moncrieff's work on the limits of pharmacotherapy.

The mainstream defence: mental illness, however philosophically loaded the category, identifies real suffering with real consequences (suicide, disability, premature mortality), and treatments that reduce suffering — even imperfect treatments — are worth having. The two positions have been in productive tension for sixty years.

The contemporary service-user / survivor movement (Mind Freedom, ISEPP, the recovery movement) is a softer descendant.

Chapter XVIIIMental illness across cultures.

The cross-cultural psychiatric literature has documented both convergence (schizophrenia and bipolar disorder show similar prevalence and presentation across most studied cultures) and divergence (depression's symptom profile, the DSM concept of personality disorder, somatoform expressions of distress).

Some culture-bound syndromes: amok (Malaysia), ataque de nervios (Caribbean), koro (East/South-East Asia, fear of genital retraction), taijin kyofusho (Japan, social anxiety focused on offending others). The DSM-5 includes a "Cultural Concepts of Distress" appendix.

The argument: Western psychiatric categories are partly cultural artefacts. The 1992 WHO IPSS schizophrenia outcome study famously found better recovery rates in three developing countries (India, Nigeria, Colombia) than in developed ones — a finding that has held up partially in subsequent work and remains hard to fully explain.

Global mental health (Vikram Patel's work; the Lancet commissions) has tried to extend evidence-based treatment to low-resource settings while avoiding cultural imposition. The tension is not fully resolved.

Chapter XIXSuicide research and prevention.

The single most important clinical concern. About 90% of suicide deaths occur in people with a diagnosable mental disorder, most commonly depression, bipolar disorder, schizophrenia, and substance use disorders.

The most predictive single factor: prior suicide attempt. Other strong factors: family history of suicide, access to lethal means (firearms specifically), severe insomnia, recent psychiatric hospitalisation, hopelessness.

What works for prevention

Means restriction — making lethal means harder to access. The UK switch from coal-gas to natural gas in the 1960s halved the suicide rate; firearm restrictions reduce suicide in jurisdictions that implement them. DBT for chronically suicidal individuals. Lithium reduces suicide independently of its mood-stabilising effect. Caring contacts — sustained low-intensity follow-up after psychiatric discharge (Motto's seminal trial in 1976).

The Marsha Linehan rule: when working with chronically suicidal patients, the therapist's job is to keep them alive long enough for the therapy to work.

Chapter XXThe trauma turn.

The 2010s and 2020s have been the period when trauma — and especially developmental and complex trauma — has reorganised much of clinical psychology. Concepts that were marginal in 1990 (CPTSD, attachment trauma, somatic-experiencing approaches) are now mainstream.

The major shift: "What happened to you?" rather than "What's wrong with you?" — Bruce Perry's reframing. Trauma-informed care now structures clinical training across psychiatry, psychology, social work, and medical specialties.

Evidence-based trauma treatments

Cognitive Processing Therapy (CPT), Prolonged Exposure (PE), EMDR, Trauma-Focused CBT (TF-CBT for children). All have strong meta-analytic support.

Open questions

The trauma turn has been criticised for: over-broadening the concept of trauma; under-specifying the difference between PTSD and ordinary distress; some over-claiming about somatic memory and the brain. The field is currently working through which aspects of the trauma framework are scientifically robust and which are popular extensions.