Each plant or strain within the Cannabis species produces subtlety different effects upon the individual user.
There are two specific types of Cannabis plant, the Sativa and Indica.
These share different qualities and originally came from different parts of the world’s ecosystem.
The Sativa Plant: The Sativa plant has thinner longer leaves and grows tall and lanky. The effect provided is often characterized as uplifting and energetic. The effects of Sativa marijuana are mostly cerebral. They give a feeling of optimism and well being, as well as providing a good measure of pain relief for certain symptoms. A few pure Sativas are also very high in THC content. They are known to have beneficial anti-depressant qualities and medicinal effects on a range of medical conditions. Sativas are a good choice for daytime smoking.
The Indica Plant: The Indica plant has fat, wide leaves and grows short and dense in structure. Most often described as delivering pleasant relaxation, stress relief, and for an overall sense of calm and serenity. Marijuana Indicas are also very effective for overall body pain relief, and often used in the treatment of insomnia. They are the late evening choice of many users as an all night sleep aid.
I do not profess to be an expert on other conditions bar my own. Sativa plants eliminate my depression and give me energy while Indica plants work to make me a more socially rounded and calm individual. They also assist in keeping any manic symptoms at bay via assistance with sleeping.
You can mix Sativa and Indica plants as I did, to achieve a mixed "high" or effect. You can mix the plants via specific single or multi-generational breeding programs to achieve any ratios you like. Typical examples would be 50/50, 60/40, 20/80 etc.
Each individual Cannabis plant, even plants of the same type has unique properties. Each plant can give a different type of mental and physical effect, as well as taste and smoking qualities. If you had enough plants and the dedication to hand breed them, as I did, in my case over 100 individual plants, you will find some plants agree with your medical requirements more than others. Each plant is made of a different range of psychoactive ingredients, this goes beyond a simple THC and CBD ratio and there is a unique signature to each plant.