Selective serotonin reuptake inhibitors, SSRIs, are medications that block serotonin from degradation. This allows a higher amount of serotonin to stay around for longer, acting as a mediator of information between neurons trying to speak to each other. Although one can state that ‘a higher amount of serotonin leads to less anxiety and depression’, the truth is likely more complicated. For example, it would be fair to consider the idea that SSRIs work by desensitizing certain neurons, or indirectly by changing feedback loops. This extra layer of complexity is part of why SSRIs can behave unexpectedly for certain people.
There are some people who benefit from a surprisingly low dose of an SSRI. Responding to an extremely low dose can indicate a higher risk of having negative side effects when given “normal doses” of SSRIs. This is to say that there are doses that other well-intentioned healthcare professionals may see as “placebo doses” ; however, this is not the case.
There are common characteristics of people who respond to low doses of SSRIs.1) These people often have a family history of bipolar disorder and/or 2) people whose depression responds to the addition of a mood stabilizer despite not having met the criteria for a diagnosis of bipolar disorder.
It may also indicate a better response to non-serotonergic medications such as bupropion.
Many people experience worsening mood, irritability, and behavioral changes on SSRIs. This can be surprising to many patients and families, however, this is very common. Continuing to take SSRIs or even increasing the dose could lead to further destabilization and worsening mood. These are due to hidden variables.
There are other people that seem to start SSRIs and may not feel improvement in symptoms until they reach moderate to high doses. These are people who seem to have a “low sensitivity” to serotonin medications. They are likely to have the diagnosis of “obsessive-compulsive disorder.” They tend to have obsessive thinking that is not connected to mood states.
Sometimes obsessive thinking occurs as a result of certain mood states; this is more in line with a mood disorder. Other times, obsessive thinking occurs as an attempt to suppress mood states.
Different SSRIs have different effects. Although they all are grouped under the domain of “SSRIs”, there are some SSRIs that are more activating than others (a spectrum between feeling more alert to feeling panicky). There are some SSRIs that are more “stabilizing” than others. There are some SSRIs that make people feel more social. There are some SSRIs that allow people to have a better mood versus anxiety. Mood and anxiety are inextricably linked and the relationship is complex. For our purposes, anxiety represents an over-reliance on awareness for the creation of ‘safety’, while mood represents ingrained feelings on what is or is not possible. These aren’t mutually exclusive and can theoretically be used in an equation to describe each other.
There are some SSRIs that seem to treat anxiety better than they do mood. For example, Fluoxetine, otherwise known as Prozac, seems to be more stabilizing, and less associated with weight gain. The side effects of fluoxetine often include feeling flat, which can be seen months after initiating the medication. For some, fluoxetine can increase migraine headaches and sight/sound sensitivity. For others, these symptoms are reduced with fluoxetine.
Some SSRIs are better taken in the morning versus at night. For example, typically escitalopram is typically better taken before bedtime, while sertraline is typically better taken in the morning. However, many people may experience a mild cognitive dullness with sertraline in the morning and have a much better experience with taking it in the hours leading to bedtime.
The point is that SSRIs can cause different effects in the hours after taking a dose which overlays the cumulative effect of having taken the SSRI over the course of 4 to 6 weeks.
The benefit of SSRI treatment is subtle. The benefit of treatment is often insidious. Someone may notice (or be noticed by others) that they are feeling less obsessed or threatened by lower priority issues, while feeling more selective with attention paid to what the logical mind determines to be more ‘pressing’.
Often, when people get better, they may have forgotten what it feels like to feel ‘stuck to low priority worries’. There may be an urge to reduce or get off medication. We generally support such requests as they are opportunities to get information on the progress of therapy, the ‘stickiness’ of the condition, or the ability to see symptoms with a more experienced eye. This must be done with an eye for return of symptoms and with a promise to observe, not to confirm/deny some judgment of ‘a personal failure to avoid dependency on a pill’. The condition of feeling the inhospitable pressure of obsession is influenced by our brains, not by our logic.
If an SSRI is reduced or stopped, it can take anywhere between 2 weeks to 6 months to see a reappearance of symptoms (i.e. feeling inclined to maintain awareness and mental energy to low priority subjects, or feeling a heightened threat potential when there is an attempt to reduce awareness for an issue).