Rather than turning to a shrink for some prescription drugs, why not take a walk on the more natural side and invest in one of nature's oldest feel good remedies that also can improve your cognitive function.
Related - Probiotic Supplements, Depression, Anxiety and Brain Health
We're digging into sceletium tortuosum today, and if you tried it before, you'll be running to grab some after reading this!
What is Sceletium Tortuosum?Also known as kanna, sceletium tortuosum is a herb traditionally chewed prior to stressful situations. You may also have seen it marketed under the brand name of Zembrin®, which is a 2:1 concentrated dose of the plant in pill form, but more on that in a bit.
Sceletium tortuosum has been used for hundreds of years by South Africans to improve mood and cope with stressful situations. 
In fact, some accounts state that small doses of the herb mixed with a teaspoon of breast milk have been used in rural areas as a remedy for children battling cholic -- interestingly enough, this practice still takes place in rural areas to this very day!
Although the plant was chewed fresh at times, it was also dried and used to make tinctures (medicines) and teas. Some less common methods of consuming kanna included smoking or inhaling as snuff, usually alongside a host of other herbs.
The age old herb was also highly valuable in ancient cultures as it was used as a form of currency in bartering communities.
How Does Kanna Work?Now that we have an understanding of what this ancient medicinal plant is, let's dive a little deeper into the the specific actions kanna enacts on the body. Kanna primarily functions in two specific ways when consumed:
Serotonin BoosterAs mentioned up top, kanna is a psychoactive herb known to induce CNS-stimulation; however, it is not known to be hallucinogenic or habit forming (what a relief!).  Kanna is replete with a number of potent alkaloids which give it its mood-elevating qualities, but researchers have identified mesembrine, and its related compounds, as the specific alkaloid responsible for its uplifting effects. 
Mesembrine functions as a potent serotonin releasing agent.  Serotonin is a monoamine neurotransmitter regarded as being heavily involved in regulating a person's mood. In fact, research has shown that having a deficiency in serotonin is linked to the development of depression and anxiety.  The mesembrine-serotonin link doesn't end there though.
Researchers have also discovered that the alkaloid functions as a serotonin-reuptake inhibitor.  Basically, mesembrine blocks the action of the serotonin transporter (SERT), which ultimately leads to increase serotonin concentrations in body. Thus, mesembrine both directly and indirectly boosts serotonin levels in the body, making it a top choice for elevating mood.
Remember back up top when we mentioned that kanna had been extracted and standardized into a pharmaceutical called Zembrin®? The patented depression medication contains a 2:1 concentration of the plant, standardized to 0.35-0.45% alkaloids by weight of kanna. Note, Zembrin® contains about 20% mesembrine and about 60-70% of mesembrenone and mesembrenol collectively. 
PDE-4 InhibitorWhile kanna has primarily been investigated for its mood-elevating abilities, researchers have also identified it as a strong inhibitor of phosphodiesterase 4 (PDE-4).  In all likelihood, you probably have no idea what you just read, and even less of an idea why you'd want this particular enzyme stunted. Follow along
PDE-4 is an enzyme that degrades the signalling molecule cAMP. Short for cyclic adenosine monophosphate, cAMP is a compound required in the regulation of a whole host of cellular actions , including:
- Increase basal metabolic rate (BMR),
- Stimulate anabolic (muscle-building) and anti catabolic (muscle-sparing) effects,
- Promote release of fatty acids,
- Support increases in lean body mass,
- Boost testosterone levels,
- Combat diet-induced obesity
BenefitsSerotonin increase and enzyme inhibition sounds all well and good, but you're ultimately interested in how this benefits you, if at all. So, taking all the science and physiological explanations above and distilling it into poignant benefits for you the average lifter gives us the following list of benefits.
- Improved Mood 
- Reduced Stress & Anxiety 
- Improved Sleep 
- Elevated Cognitive Function 
- Combat Depression 
- Relieve Pain 
How Much Sceletium Tortuosum?Human trials using sceletium tortuosum have primarily been completed using a 2:1 Kanna extract (a.k.a. Zembrin®). Clinical trials administered single doses of 8mg or 25mg daily for three months in "otherwise healthy adult subjects" did not appear to have any negative ramifications in cardiovascular parameters (blood pressure, pulse or breathing rate). 
Basically, stick to the recommended dosing on the bottle, and you should be OK, with the understanding that you are an "otherwise healthy adult subject."
Side Effects / Toxicity ConcernsNo life threatening side effects or toxicity concerns were observed during the human trials when using the upper range dose of 25mg per day. However, a few "adverse events" were observed by researchers during the various trials. The most common ones associated with Kanna supplementation included loss of appetite, headaches, abdominal pain, and upper respiratory tract infections.
Lastly, no toxicological concerns were observed in rats when given doses of 5,000mg/kg body weight, roughly 1,800x greater than the recommended human intake, for over two weeks. Now, rat physiology is vastly different from that of humans, but this is just to drive the point home that the 25mg dose you may consume per day shouldn't pose any immediate life-threatening consequences.