Depression is a major psychiatric disorder that is associated with high rates of suicide and is considered one of the most important causes of human disability. It is well known that chamomile is one of the oldest known medicinal herbs and has been used to treat various disorders. In the present study, Roman chamomile inhalation with clomipramine treatment improved depression-like behavior, hippocampal neurogenesis and serum corticosterone levels.
Approximately 30% of patients who suffer from a major depressive disorder do not respond sufficiently to established pharmacological, psychotherapeutic or somatic treatments. In the present study, treatment with clomipramine, which is generally used as an antidepressant, did not ameliorate depression-like behavior or affect hippocampal neurogenesis or serum corticosterone levels. The results show that the 15-day chronic stress can cause treatment-resistant depression and treatment with the tricyclic antidepressants imipramine and clomipramine did not ameliorate depression-like behavior. Although administration of chamomile alone did not affect stress-induced behavioral changes, treatment with clomipramine and chamomile improved depression-like behavior, increased hippocampal neurogenesis and decreased corticosterone levels. These results indicate that chamomile could play a supplementary role in the treatment of treatment-resistant depression when administered in combination with an antidepressant.