Actigraphy can measure antidepressant-induced daytime sedation in healthy volunteers

Actigraphy is the continuous measurement of the motor component of behaviour. A change in behaviour will result in a change in activity. Drugs that are behaviourally toxic will cause changes in activity which can be measured using an actigraph. It is hypothesized that a reduction in daytime activity is a measure of sedation. A study was conducted comparing actigraphy with valid, reliable psychometric tests which are sensitive to the behaviourally toxic effects of psychoactive drugs. The study was designed to investigate whether actigraphy could accurately measure the daytime sedation associated with tricyclic antidepressants. The effects of fluvoxamine and dothiepin on behavioural activity and psychomotor abilities, in 12 healthy male volunteers, was investigated in a placebo-controlled, double-blind, crossover study. Subjects completed a battery of psychometric tests prior to dosing then at 1, 2, 3, 4 and 6 h post dose. Actigraphy showed that dothiepin caused daytime sedation, defined as a reduction in activity and this result was confirmed by the results from the psychometrics which showed that dothiepin impaired cognitive and psychomotor performance in the majority of the tests. These results show that actigraphy is capable of accurately measuring daytime sedation.