In healthy controls, preactivation of muscles by exercise results in enhanced motor-evoked potential (MEP) responses to transcranial magnetic stimulation (TMS).

We tested the hypothesis that medicated, depressed patients would show reduced post-exercise MEP facilitation compared with controls.

Ten patients with DSM-IV depression (two male, eight female) and ten controls (three male, seven female) participated. MEPs were elicited at rest, then after exercising the contralateral abductor pollicis brevis muscle, using TMS of the primary motor cortex.

The mean MEP amplitude recorded after exercise (expressed as a percentage of baseline) was 210% in controls and 130% in patients. There was a significant difference in post-exercise MEP between patients and controls (P=0.03).

Post-exercise MEP facilitation was demonstrated in controls but not in patients. This supports the hypothesis that the modulation of cortical excitability may be impaired in depression.

The past decade has witnessed a recognition that unsafe criminal convictions may be occasioned by unreliable confessions.

To present a case which illustrates the dangers of using abreaction interview techniques in a legal context and demonstrate the relevance of the memory distrust syndrome to an unsafe confession to murder.

We undertook a detailed assessment of a person appealing against his original murder conviction/the appellant’, and a careful scrutiny of all the relevant papers in the case.

The appellant served 25 years in prison before his conviction was quashed as ‘unsafe’ on the basis of fresh psychological and psychiatric evidence.

Amnesia for an offence had been misdiagnosed, and the use of repeated abreaction interviews had further confused both the appellant and the original court. At the Appeal Court, the advice was that the man had experienced a form of source amnesia which resulted in an unreliable confession.