A theoretical model explains why abnormal behavior develops, what treatment should target, and what the relationship between client and helper looks like. No single model explains every condition. Current practice uses a biopsychosocial (stress–vulnerability) approach: a biological or genetic vulnerability interacts with psychological factors and social stressors to produce illness, so care combines medication, psychotherapy, and social support.

Each model directs attention to different data:

• Psychodynamic: links between present symptoms and past developmental experiences; defense mechanisms in use
• Interpersonal: level of anxiety; quality of current relationships
• Behavioral: the specific problem behavior, its antecedents and consequences (what triggers and what reinforces it)
• Cognitive: automatic thoughts and cognitive distortions
• Biological: family history, medical illness, substance use, response to medication

Erikson's psychosocial stages (useful for developmental assessment)

Freud's structure of personality: id (pleasure principle), ego (reality principle, mediates), superego (conscience). Psychosexual stages: oral, anal, phallic, latency, genital.

Common defense mechanisms (unconscious, reduce anxiety)

Models guide which tools are used; the diagnosis itself uses standard criteria.

Treatments derived from each model:

• Psychodynamic: insight-oriented psychotherapy; brief psychodynamic therapy focused on one central conflict
• Interpersonal: interpersonal psychotherapy (IPT) for depression
• Behavioral: classical conditioning techniques — systematic desensitization (relaxation paired with a graded fear hierarchy; relaxation replaces anxiety through counterconditioning / reciprocal inhibition), exposure, flooding, aversion therapy. Operant conditioning techniques — positive reinforcement, token economy, shaping, extinction
• Cognitive: cognitive therapy (Beck), rational emotive behavior therapy (Ellis, A–B–C: activating event → belief → consequence)
• Biological: psychotropic medication (for example, an SSRI is the usual first-line drug for major depression — nausea, sexual dysfunction, hyponatremia in older adults, bleeding risk with NSAIDs or anticoagulants, serotonin syndrome with other serotonergic drugs, never with an MAOI; boxed warning for suicidality under age 25; details in Topic 9), ECT, brain stimulation
• Social: crisis services, community programs, prevention

Reinforcement terms (commonly confused)

Listed in priority order.

1. Safety first — whatever the model, assess suicide and violence risk before exploring causes.
2. Build the relationship (Peplau's interpersonal model) — nursing is a therapeutic interpersonal process. Phases:
   • Orientation: client seeks help; nurse and client get acquainted, set goals, and plan termination
   • Working (Peplau's original identification and exploitation phases): client identifies with the nurse, then makes full use of services
   • Resolution: client meets goals, becomes independent, and uses the relationship as a model for healthy relationships
   • Nurse roles: stranger, resource person, teacher, counselor, surrogate, leader
3. Manage anxiety (Peplau's four levels) — mild (learning improves), moderate (selective attention), severe (narrowed focus, cannot solve problems), panic (disorganized; safety and brief directions needed)
4. Apply model-matched techniques
   • Cognitive: "That thought may be making your mood worse. Let's look at the evidence for it together."
   • Behavioral: reward target behaviors consistently; do not reinforce problem behavior with attention
   • Humanistic: accept the person while not accepting harmful behavior
5. Integrate models — combine medication adherence support with psychotherapy and social support; no one model fits every client.
6. Use trauma-informed care — SAMHSA principles: safety; trustworthiness and transparency; peer support; collaboration and mutuality; empowerment, voice, and choice; cultural, historical, and gender issues.

• Explain that mental illness usually results from several interacting factors, not personal weakness
• Describe what the chosen therapy involves (homework in CBT, exposure steps in desensitization)
• Medication plus therapy often works better than either alone for many conditions
• Recovery is possible: the goal is a meaningful life, not only symptom removal
• Teach families the stress–vulnerability idea: lowering stress and supporting routines protects against relapse

• Free association and dream analysis = psychoanalytic (Freud); focus on unconscious conflict and defense mechanisms, linking present symptoms to past development
• Peplau = interpersonal model; the nurse–client relationship is the treatment; phases orientation → working (identification, exploitation) → resolution
• Rogers: empathy, unconditional positive regard, genuineness — not professional authority
• Behavioral: learned behavior; systematic desensitization = relaxation + graded exposure (counterconditioning)
• Negative reinforcement increases a behavior by removing something unpleasant
• Cognitive (Beck, Ellis): distorted thoughts cause distress; Ellis A–B–C, B = belief
• Communication model: goal is clear, direct, congruent messages
• Existential: here and now, personal responsibility
• Biological: neurotransmitters; SSRIs first-line for depression
• Projection = attributing own unacceptable feelings to others; displacement = redirecting to a safer target
• Modern care = biopsychosocial integration plus trauma-informed care