Risk assessment instruments have become a preferred means for predicting future aggression, claiming to predict long-term aggression risk.

To investigate the predictive value over 12 months and 4 years of two commonly applied instruments (Historical, Clinical and Risk Management - 20 (HCR-20) and Violence Risk Appraisal Guide (VRAG)).

Participants were adult male psychiatric patients detained in a high secure hospital. All had a diagnosis of personality disorder. The focus was on aggression in hospital.

The actuarial risk assessment (VRAG) was generally performing better than the structured risk assessment (HCR-20), although neither approach performed particularly well overall. Any value in their predictive potential appeared focused on the longer time period under study (4 years) and was specific to certain types of aggression.

The value of these instruments for assessing aggression in hospital among patients with personality disorder in a high secure psychiatric setting is considered.

The dopamine hypothesis proposes that antipsychotic drugs act primarily through limbic cortical D2/D2-like dopamine receptor blockade.

To evaluate this hypothesis with the D2/D3-selective SPET probe [123I]-epidepride.

[123I]-epidepride SPETscans were performed on 12 patients with schizophrenia treated with antipsychotics and 11 age-matched healthy controls. [123I]-epidepride specific binding to D2/D3 dopamine receptors was estimated, and relative percentage D2/D3 receptor occupancy by typical antipsychotic drugs determined.

Mean (s.d.) daily dose was 669.12 (516.8) mg chlorpromazine equivalents. Mean percentage D2/D3 receptor occupancy was 81.6 (8.1) and 73.2 (13.9) in the temporal cortex and striatum respectively.

Typical antipsychotic drug treatment is associated with substantial temporal cortical D2/D3 receptor occupancy. The relationship between this and efficacy is poor in patients with treatment-resistant schizophrenia.