Inositol is a naturally occurring carbohydrate which is sweet in taste, and is an isomer of glucose. Inositol can be found in fruits and lechitins. Inositol is a key component of the phosphatidyl-inositol cycle, which is a second-messenger system used by serotonergic, noradrenergic, and cholinergic receptors. The reported mechanism of action of inositol is to reverse the desensitization of serotonin receptors, thereby effectively increasing the signal of the serotonin receptor downstream (Levine, 1997). This is hypothesized to have similar effect as SSRIs (selective serotonin reuptake inhibitors) to decrease the reuptake of serotonin in the synapse, thereby increasing serotonin in the synapse and increasing the signal from the serotonin receptor postsynaptically.
One study found that inositol was as effective as fluvoxamine for the treatment of panic disorder (Palatnik et al., 2001), while a different study found inositol to be more effective than placebo for panic disorder (Benjamin et al., 1995). Another study found it effective in obsessive compulsive disorder (OCD) (Fux et. al., 1996). Inositol is a natural compound with few side effects, which makes it an attractive alternative to psychotropics which have significant side effects.
Lavender, also known as Lavandula angustifolia, is a flowering plant in the mint family, and is native to the Old World. It is hypothesized that lavender has benzodiazepine-like action, without the side effects of benzodiazepines, such as tolerance, dependence, and abuse potential (Silenieks et al., 2013).
In a study that was just published, Kasper et al. (2014) studied lavender oil, Silexan, comparing it to placebo and paroxetine in an RCT for generalized anxiety disorder, and found that lavender oil was more effective than placebo for anxiety. In addition, lavender oil had fewer side effects than paroxetine, and had a side effect profile comparable to the placebo (Kasper et al., 2014). Another study showed that lavender oil was as effective as lorazepam for generalized anxiety disorder, and does not have the sedative or addictive potential of benzodiazepines (Woelk and Schläfke, 2010). Additionally, lavender showed effectiveness for subclinical anxiety when compared to placebo, and improved anxiety related disturbed sleep without causing sedation (Kasper et al., 2010).
Passiflora incarnata, commonly known as Passionflower, is a flowering plant, and has a pantropical distribution. Passiflora modulates the GABA system by binding to GABA receptors and inhibiting the reuptake of GABA (Appel et al., 2011).
One study revealed that Passionflower was as effective as oxazepam for generalized anxiety disorder, and that oxazepam caused impairment in job performance (Akhondzadeh et al., 2001). Another study showed that Passiflora reduces anxiety in surgery patients pre-operatively (Movafegh et. al., 2008). Additionally, Passiflora tea improved sleep in people with mild sleep problems when compared to placebo tea (Ngan and Conduit, 2011).
L-theanine is an amino acid found in green tea. The mechanism of action of l-theanine for its anxiolytic and calming effect is due to the up-regulation of inhibitory neurotransmitters such as GABA, and it may also modulate serotonin and dopamine neurotransmitters (Lardner, 2014).
In one study, theanine reduced anxiety symptoms more than placebo in healthy subjects (Unno et al., 2013). In another study, L-theanine augmentation of antipsychotic medications for those with psychosis was more effective than placebo augmentation for reduction of anxiety symptoms (Ritsner et al., 2011). L-theanine can also cause a relaxed state while also improving concentration (Kobayashi et al., 1998).
Melissa officinalis, commonly known as lemon balm, is a herb in the mint family, and native to Europe and the Mediterranean. The mechanism of action of lemon balm appears to decrease corticosteroids and increase GABA levels (Yoo et al., 2011).
One study showed that lemon balm combined with Valerian led to anxiolytic effects in healthy subjects when compared to placebo (Kennedy et al., 2006), and another study showed it reduced stress in healthy volunteers (Kennedy et al., 2004). Additionally, a study showed effectiveness for mild to moderate anxiety disorders and sleep disturbances (Cases et al., 2011).