In over three decades of clinical practice, one of the patterns I have watched play out again and again is what happens after someone is first prescribed an antidepressant. It rarely stays a single medication for long. Side effects appear, so something is added to manage the side effects. Sleep becomes disrupted, so a sedative or sleep aid joins the regimen. Mood becomes unstable in a new and different way, so an antipsychotic or mood stabiliser is introduced to smooth that out. Within a few months or years, someone who started on one tablet for what may have been a genuinely difficult period in their life is often on three or four medications, none of which were ever properly reviewed together, and nobody quite remembers how they got there. This is sometimes called a prescribing cascade, and I see it constantly in clinic. It is one of the reasons I take antidepressant prescribing so seriously as a subject, rather than treating it as a simple, settled matter of chemistry corrected.

Antidepressants are not neutral, and their reach extends well beyond serotonin. Most people are told that SSRIs work by raising serotonin levels, but research has shown the picture is considerably more complicated, and dopamine is very much part of it. Serotonin and dopamine signalling interact closely within the brain's reward circuitry, and studies have found that elevated serotonin caused by SSRIs can actually be taken up by dopamine transporters in the striatum, effectively hijacking dopamine signalling pathways and altering the way reward and motivation circuits fire. This offers a plausible biological explanation for something many people on long term SSRIs describe but rarely have named for them by their prescriber, a flattened, muted quality to life often called emotional blunting, where positive experiences stop registering with the same intensity and motivation quietly erodes. Clinically I see this constantly, people who are technically no longer depressed by the measures used to assess them, but who also no longer feel very much of anything, and who have lost the drive and reward response that once made ordinary life feel worth engaging with. This is a real pharmacological effect on dopaminergic function, not a personal or psychological failing, and it deserves to be discussed as openly as the effect on serotonin itself.

The nutrient picture compounds this further. SSRIs have been associated with reduced levels of vitamin B6, vitamin B12, folate, melatonin, CoQ10, selenium, magnesium and zinc over extended use, and each of these plays a direct role in exactly the systems the medication is meant to be supporting. B6, B12 and folate are essential to methylation, the biochemical process the body relies on to manufacture serotonin, dopamine and noradrenaline in the first place, which means long term depletion can leave the nervous system with fewer raw materials to build these neurotransmitters even while medication continues trying to manage the ones already in circulation. Magnesium and zinc are similarly critical for neurotransmitter regulation and for calming an overactive nervous system, and depletion of either can present as increased anxiety, muscle tension or disrupted sleep that gets read as a return of the original illness rather than a consequence of treatment. Melatonin depletion deserves particular attention too, since SSRIs appear to interfere with its natural secretion, and melatonin is not simply a sleep hormone but one of the brain's most important antioxidants, protecting neural tissue from oxidative stress.

Then there is the question of what happens when someone tries to stop. Antidepressant discontinuation syndrome is well documented and, in my clinical experience, significantly underestimated in how it is discussed with patients at the point of prescribing. The nervous system adapts to the presence of these medications over time, including genuine changes in receptor sensitivity, and withdrawing too quickly, or sometimes even tapering carefully, can produce dizziness, electric shock sensations, severe anxiety, insomnia, mood instability and flu-like symptoms that can last weeks or months. Many people are told these medications are not addictive in the pharmacological sense that substances of abuse are, which does nothing to describe the lived experience of someone trying to come off them after years of use, feeling genuinely trapped by a medication they no longer want to be on.

The mania risk is something else that deserves far more attention than it typically receives. Antidepressants, and SSRIs in particular, have been associated with switches into hypomania or mania, most significantly in people with an underlying vulnerability to bipolar disorder that had not yet been identified at the point of prescribing. Research has shown that patients who experience this kind of switch often share clinical features with bipolar populations more broadly, and family history of mood elevation appears to be a meaningful predictor. In practice this means a young person struggling with what looks like straightforward depression can be started on an antidepressant, only to be pushed into a manic or hypomanic episode that then gets treated as the emergence of a new and more severe diagnosis, sometimes leading to antipsychotic treatment that would never have been needed had the underlying vulnerability been identified first. I have seen this happen within my own family, and it is precisely this kind of pattern, medication as trigger rather than medication as neutral treatment, that most conventional prescribing conversations simply do not make space for.

None of this means antidepressants should never be used, and I want to be clear that stopping or changing any psychiatric medication should only ever be done gradually and under proper medical supervision, given everything described above about discontinuation and mood destabilisation. What it does mean is that long term treatment deserves a far more complete picture than a repeat prescription and an annual check-in can offer, and this is exactly the kind of picture I spend my time building with people.

I use Lifecode Gx genetic reports focused on the nervous system to look at specific genes known to shape antidepressant response and risk. SLC6A4, the serotonin transporter gene, influences how strongly someone responds to SSRIs and how likely they are to experience side effects. HTR2A, which codes for a serotonin receptor, has repeatedly been linked to differences in antidepressant response and tolerability. COMT governs how efficiently dopamine is broken down in the prefrontal cortex, which matters enormously given what we now understand about SSRIs and dopaminergic blunting, since someone with a slower COMT variant may already be running higher baseline dopamine and could experience the dopamine-dampening effects of an SSRI quite differently to someone with a faster variant.

MTHFR affects how efficiently someone converts folate into the active form the brain needs for neurotransmitter synthesis, directly compounding the folate depletion antidepressants themselves can cause. And pharmacogenomic pathways such as CYP2D6 and CYP2C19 determine how quickly someone actually metabolises these medications, meaning a poor metaboliser may be accumulating far higher effective drug levels than their prescribed dose suggests, which can explain both heightened side effects and a more difficult withdrawal. This genetic layer is something I have built out in real depth as part of my own Gene-Drug Reference Series work, precisely because so few people are ever told that their own genetics might explain why a medication affected them so differently to how it affected somebody else.

Alongside genetics, I look at gut function through GI-MAP testing where relevant, since digestion and absorption directly affect how well someone can access the nutrients their nervous system depends on regardless of how carefully they are eating. And because I work through Mindscaping, the deeper emotional and nervous system patterns underlying how someone experiences stress and mood, I am able to hold the biochemical picture and the psychological one together rather than treating them as separate conversations. Someone on long term antidepressant treatment is very often also carrying nervous system dysregulation that predates the prescription itself, and no amount of genetic insight or nutrient repletion alone will resolve that if the deeper pattern is never addressed.

From there, support is built around what someone's genetics and testing actually reveal. If you or someone you love has been on an antidepressant for a long time and has noticed a flattening of feeling, a loss of drive, sleep and energy that no longer feel steady, or if coming off has felt far harder than anyone warned it would be, it is worth understanding the fuller picture of what has actually been happening in the body throughout treatment.

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