The range and intensity of effects produced by a substance depends on upon a number of factors, including personal and environmental factors, route of administration, and dosage. Effective dosages can be divided into five categories: threshold, light, common, strong, and heavy.
A threshold dose is the dose at which the mental and physical alterations produced by the substance first become apparent. These effects are distinctly beyond that of placebo, but can be ignored with some effort by directing one's focus towards the external environment. Users may perceive a vague sense of "something" or nervous energy building up in the background at this level.
A light dose produces effects which are noticeable and clearly distinct from sobriety but remain in the background of the user's awareness. The effects can be ignored by increasing the focus one directs towards other things when performing complex tasks. The user may have to pay particular attention to the effects of the substance for them to be recognizable, or they may be slightly noticeable but will not insist upon the user's attention.
A common dose is the dose at which the effects and the nature of a substance is quite clear and distinct and ignoring its action becomes difficult. The user will generally be able to partake in regular behaviors and remain functional and able to communicate. The effects can be allowed to occupy a predominant role or they may be suppressed and made secondary to other chosen activities.
A strong dose renders its subject mostly incapable of functioning, interacting normally, or thinking in a sober manner. The effects of the substance are clear and can no longer be ignored, leaving the user entirely engaged in the experience whether they wish to be or not.
A heavy dose is the upper limit of what a substance is capable of producing in terms of perceptible characteristic effects. Depending on the substance consumed, the user may be rendered incapable of functioning and communicating and experience extremely uncomfortable side effects that may overshadow the positive effects experienced at lower doses.
An overdose is a quantity greater than recommended, intended or generally practiced, with the possibility of the dose resulting in serious injury or death. Immediate professional medical advice should always be sought when a user has taken a dose greater than or equal to this, although tolerance may allow experienced users' bodies to survive such doses. It should be noted that doses below this level may also be harmful in some cases.
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