The shorter the half life the harder it is to come off of and more emotionally painful is after missing just one day.
Very much agree with Amy in the quote above.
While I'm not a doctor, here's some information that I hope can be of assistance when you start. This is stuff that prescribers are trained to communicate to their patients, but which many don't for whatever reason. I'd really encourage you to internalize it or consult it when necessary as some of these things can sneak up on you.
(Also, note that this information is regarding SSRIs. While these are by-far the most common kind of antidepressant, if you're prescribed an antidepressant of another class (e.g. a SNRI, TCA, or MAOI) this information may not be applicable):
- Antidepressants work very well for some, but not others. Approximately one third (33%) of patients achieve a (near-)complete remission of depressive symptoms, another third experience some partial benefit, and the last third have little-to-no response/change. That antidepressants may or may not work doesn't mean you should or shouldn't try them, especially if you've nothing else to lose.
- After starting an SSRI, it generally takes 2-6 weeks for the medication to become effective. This onboarding process, while temporary, is sometimes characterized by side effects such as spiked anxiety/panic, insomnia, gastrointestinal issues, and fatigue.
- While on an SSRI, one must necessarily note that the medication is only a partial aid; they are not magic pills and they can't fix one's life. Effort needs to be put forth by the individual to improve things for themself independent of the medicine. Not making this effort is how one ends up reliant on a medication for far longer than they would otherwise need to be. That all said, the medicine does ideally make it much easier to actually begin an instantiation of change within one's life.
- Exercise on its own produces an antidepressant effect similar to many medications in the general person. When exercise is combined with an SSRI, additional benefit is produced.
- Antidepressants often cause side effects such as emotional blunting, lowered libido, insomnia, and reduced REM sleep, among other things. These tend to be manageable and worth dealing with if the medication is otherwise working. That said, if side effects are intolerable at this point, a determination related to continuing/discontinuing the medication should be considered by the individual.
- If things are well on the medication, one should generally stay on an SSRI for a period of ~6 months
after a remission of depressive symptoms to prevent relapse. While staying on a medication dramatically longer than this is not the end of the world, it does unnecessarily expose you to the aforementioned side effects for longer and it can make discontinuation harder. Likewise, one shouldn't rush to discontinue a medication prematurely / if things aren't 100%.
- When ready to discontinue, one should taper. Tapering is the gradual reduction of a medication's dose and is often integral in preventing discontinuation / withdrawal symptoms with SSRIs. Often, tapering manifests through a halving of the medication every few weeks until the lowest manufactured dose is reached. One can request and continue with a liquid formulation if they wish to be extra careful, though this isn't always necessary. While all doctors are trained in the tapering process, they don't all engage it without being asked. Generally, though, it's very much worth tapering for the two reasons below.
- With chronic use, it takes approximately 2-8 weeks after one's last dose for an SSRI to be considered both out of one's system and successfully discontinued. While many don't experience any terrible side effects during this period of brain readaptation, feelings such as immense fatigue, brain fog, 'brain-zaps', severe insomnia, increased anxiety, itching, irritability, a resumed depression, and, potentially, suicidal ideation are common. The extent and duration of these symptoms, however, varies based on the medication's half life, individual brain neuroplasticity (often correlated with age and exercise), whether tapering occurred, and how long one was on the medication. Good sleep and legitimate exercise during this process help
immensely. (Like, really, a lot.)
- Antidepressants with very short half-lives (e.g. SSRIs like Paroxetine/Paxil and SNRIs like Cymbalta/Duloxetine & Effexor IR) are less commonly prescribed, but are very difficult to discontinue. Generally, they should be avoided if possible as other medications in the same class with longer half lives exist and accomplish largely the same things. If one is on a short acting SSRI, it's possible to switch to a medication of the same class with a longer half-life (E.g. Prozac/Fluoxetine) for a few weeks prior to discontinuing. This is called 'bridging.'
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Overall, I'd recommend giving them a shot! While some of these things can sound overbearing or frightening, it's basically all temporary stuff and very much worth it if the medication is effective! If you take exercise, sleep, and other mentioned things seriously during the onboarding and offboarding processes, you shouldn't have any significant issues and the medicine can really serve as a springboard to get you into a better place mentally and otherwise.