Background: Depression is a mood disorder that causes a persistent feeling of sadness and loss of interest in the usual activities. According to WHO, depression has been estimated to affect up to 21% of the world's population, while two recent cross-sectional studies conducted in the Kingdom of Saudi Arabia show that about 50% of the population is suffering from mild to severe depression.
Objective: Since the adverse effects associated with the current anti-depression medications are severe, the current study aimed to test the anti-depressant effect of natural oils, including almond oil, along with the inhalation of lavender oil, for alleviating depression.
Methods: Male Wister rats weighing approximately 250-300 g were used for the study. Almond oil was given to rats through oral or intraperitoneal injection (3.2 g/kg). Inhalation of lavender oil (diluted with water; 1: 20) was given to rats for a period of 30 or 60 min. The anti-depressant effect of the natural oils was evaluated using two different methods, either the forced swim test or the passive avoidance test. Results: The anxiety and depression associated with forcing the rats to swim is reduced by the treatment with almond oil alone and in combination with the inhalation of lavender oil. The treatments resulted in the reduction of immobility events and an improvement in climbing behavior. Furthermore, the treatment of rats with almond oil alone and in combination with lavender oil inhalation increased the latency period to avoiding the shock in the passive avoidance test apparatus. The combination therapy resulted in a significant additive effect in the passive avoidance test.
Conclusion: Our results indicate that the treatment with almond oil or the combination of almond oil with the inhalation of lavender oil show anti-depressant-like effects in the rats studied, using the forced swim test and the passive avoidance test as evaluation tools.