Treatment models.

Antipsychotic drugs are used in a range of schizophrenic patients from the acutely disturbed to the chronically inert. Acute psychotic breakdowns usually involve secondary phenomena such as anxiety, depression and hostility superimposed on a worsening of the psychotic illness: a threshold of arousal is exceeded. This sets up a vicious circle which requires a major therapeutic effort to interrupt. Unfortunately, patients still relapse despite apparently adequate medication, suggesting only partial protection. Relapse is influenced by drug-related factors such as compliance and substance abuse, psychological factors such as cultural context, family dynamics and life events, and illness features such as poor insight. Treatment strategies, such as low-dose and intermittent medication, have proved disappointing. The most pragmatic model is the classic stressor-vulnerability model, but this does not explain the enhanced efficacy of clozapine.