Antipsychotics in depot (or ‘long-acting injection’, LAI) form are shown in this supplement to be a significant component of clinical practice. They are comparatively underresearched, which may reflect their frequent use witih poorly adherent patients. This supplement clearly demonstrates the need for that research, highlighting the variations in dosing and the absence of established, specific guidelines in their use. Traditional evidence-based approaches to systematic reviews are of limited utility in this area so this supplement's blending of experimental trials with observational research is particularly appropriate and effective. After a brief decline in their use with the introduction of oral atypical antipsychotics, LAIs are regaining a central position in the care of long-term psychosis. This comprehensive review of current knowledge makes a timely contribution.