Chapter 13-04: Diseases & Pathophysiology in Psychiatry

PSYCHOTIC DISORDERS

Schizophrenia

• Etiology: Likely multiple diseases with similar signs/symptoms (Neuropsychopharmacol 2009;34(9): 2081).

• Pathophysiology: Dopamine hypothesis of schizophrenia suggests that excess dopamine in mesolimbic tract causes positive psychotic symptoms, although other neurotransmitters are likely involved; anti-psychotics used for treatment block dopamine, consistent with the dopamine hypothesis

• Epidemiology: ~1% population. M:F = 1.4:1. Onset in men 18–25 yr, women 25–35 yr. Better prognosis if late onset, positive symptom predominant, and good social support.

• Symptoms: Divided into positive and negative symptoms; negative are more difficult to treat

  • - (+) Hallucinations, disorganized speech

  • - (–) Blunted affect, apathy, isolation, cognitive impairment

• Phases: 1) Prodromal (irritable, isolation); 2) Psychotic; 3) Residual (persists between psychotic episodes: Flat affect, isolation) (Figure 13.2)

• Diagnosis: ≥6 months with two or more of 1) Delusions; 2) Hallucinations; 3) Disorganized speech; 4) Disorganized or catatonic behaviors; 5) Negative symptoms (flat affect). Significantly affects function. Imaging not required for diagnosis, but MRI brain may show enlargement of the cerebral ventricles.

• Subtypes: 1) Paranoid; 2) Disorganized; 3) Catatonic; 4) Residual (mostly negative symptoms); 5) Undifferentiated

• Treatment:

  • - Typical antipsychotics: Haloperidol, chlorpromazine, thioridazine; use depot/decanoate versions of drugs if poor compliance. Several clinically important clinical syndromes can result as side effects:

    • Acute dystonia: Involuntary contraction of major muscle groups. Treatment: Benztropine, diphenhydramine

    • Akathisia: Motor restlessness. Treatment: Propranolol

    • Parkinsonian: Mask-like facies, resting tremor, cogwheel rigidity, shuffling gait; Treatment: Benztropine, amantadine

    • Tardive dyskinesia: After chronic use; sucking/smacking lips, facial grimacing, choriform movements. Treatment: Stop medication

    • Neuroleptic malignant syndrome (NMS): Tetrad of fever, rigidity, mental status changes, and autonomic instability. Treatment: Stop medication and admit to ICU

  • - Atypical antipsychotics: Olanzapine, quetiapine, risperidone, aripiprazole, clozapine, ziprasidone. Side effects: Metabolic syndrome especially olanzapine and clozapine. Only use clozapine if patient has failed other options, due to risk of agranulocytosis.

Other psychotic disorders

• Schizophreniform: Same as schizophrenia but only 1–6 months (Think “forming”)

• Brief psychotic disorder: <1 month. Rare, often in response to trauma or stress.

• Schizoaffective: Schizophrenia + mood disorder (depression or mania). Mostly mood symptoms, but must be psychosis in the absence of mood symptoms 2+ wks (i.e, if psychotic features only occur during mood symptoms, then appropriate diagnosis is MDD or bipolar disorder with psychotic features).

• Delusional disorder: Non-bizarre fixed delusion for 1+ month (e.g., thinks food is poisoned) but does NOT interfere with daily function.

• Shared psychotic disorder: Folie a duex (“madness for two”). Same symptoms as loved one. Treatment: Separation.

• Secondary to medical condition: 1) CNS disease; 2) Endocrinopathy; 3) Nutritional deficiency (B12, folate, niacin); 4) Other: SLE, porphyria

• Secondary to medications or substance abuse: Steroids, antiparkinsonians, anticonvulsants, antihistamines, anticholinergics

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