Richard Wessler et al developed the concepts of “emotional set point” and “threshold of stimulation” in his books and lectures. He understood how both are originally genetic, then epigenetic, then increasingly influenced by both life experience and the current environment. The former is one’s “typical emotional state at rest” (meaning not stressed by exogenous factors; exogenous means “coming from outside”). The latter means “level at which one is triggered by either edogenous (meaning “coming from inside”) or exogenous stimulations.”
According to Hamilton & Timmins, renown experts in addiction pharmacology, as well as Wessler et al, as well as George Koob’s world-famed crew of researchers down at U. Cal. San Diego, one can infer that…
The so-called “average” person would have an “average” emotional set point (ESP) and threshold of stimulation (ToS). Introduce exogenous depressants (e.g.: benzodiazepines, dopamine channel blockers, opiates, etc.) into their nervous systems, and their ESP will move downward at first, then upward over time, while their ToS will also move up. Introduce exogenous stimulants (e.g.: amphetamines, cocaine, caffeine, etc.) into their systems, and their nervous systems, and their ESP will move upward at first, then downward over time, but their ToS will still move up.
Rapid cycling (or “cylcothymic”) bipolars (strongly co-morbid with sz, btw) tend to have erratic emotional set points and high to very high thresholds of stimulation at “rest.” (I used quotation marks there because in bipolars, “rest” is not what it is in the average person. Most bipolars do not truly rest until they just “crash.”) The same initial reactions to both depressants and stimulants occur in bipolars, BUT the reactions over time are different:
Rather than a normal withdrawal phase to the opposite of the initial reaction, bipolars typically experience a confusion of the effect of the exogenous drug with their genetic endogeny. Drug metabolism sets pushes both “up” and “down” on the emotional set point in a manner most bipolars experience as “disturbing,” “agitating,” “irritating,” and “anxiety-provoking.” Many say that withdrawal is like being “panic-stricken.” At the same time, the already very high threshold of stimulation is moved upwards even further.
To (attempt to) deal with the disturbance, agitation, irritation, anxiety and/or panic, most drug users will simply try to get more of the drug that made them feel “better” into their nervous systems again. The cyclothymic bipolar, however will need more and more much more rapidly than the average drug user.
The result over time for any “addict” is almost always shorter- and shorter-term “relief,” and longer- and longer-term disturbance, agitation, irritation, anxiety and/or panic. Until – at some point – the drug is no longer able to overcome the disturbance, agitation, irritation, anxiety and/or panic. And any amount is either ineffective or enough to overload the nervous system with disastrous results, possibly including cardio suppression or over-activity sufficient to “break” the heart, and kill the person.
But for the cyclothymic bipolar, what I described just above may occur so quickly that the risk of overdose is much greater and occurs much sooner than for the average person.