Biochemistry Questions / Describe the animal models used to study depression and their relevance in assessing the efficacy of antidepressant drugs.

There are a number of animal models for depression, allowing the study of both the mental impacts of it, and drug action. The forced swimming test involves timing the duration a rodent swims for before giving up in an inescapable tank of water. On administering a good antidepressant, the rodent should swim for longer before giving up.

Learned helplessness involves placing a rodent in a cage with a floor through which an electrical current can be passed. The rodent has analgesics administered to remove the pain from the electric shocks through the floor. On repeated electrical shocks, the animal begins to become helpless. After administering an antidepressant, the animal becomes helpless after a longer period of time, improving its resilience.

These models are effective at assessing the efficacy of antidepressants, allowing the study of behavioural changes in the animals. The use of analgesics (particularly in the learned helplessness model) does not have an impact on the efficacy of the antidepressant, and so is acceptable.