Psychiatric Medicines: Why the Names Mislead

A great deal of distress in psychiatry comes from a labelling accident. Someone is given a tablet for nerve pain and reads on the leaflet that it is an antidepressant. Someone else is prescribed something for sleep and discovers it is classed as an antipsychotic. Both conclude that a diagnosis has been made behind their back and not shared with them.

Neither has. The names are historical accidents, and understanding that removes most of the alarm.

🗺️ The six groups

Look down the right-hand column and the point becomes obvious: not one of these classes is confined to the condition in its name.

💉 The clearest example

One drug demonstrates the whole problem better than any explanation.

Quetiapine at twenty-five or fifty milligrams behaves essentially as a sedating antihistamine. It is prescribed at that dose for sleep and for anxiety, and at that level it barely touches the receptors involved in psychosis at all.

The same drug at six or eight hundred milligrams is a full antipsychotic.

Same molecule, entirely different drug depending on the dose — because different receptors are occupied at different concentrations. Someone given twenty-five milligrams for sleep and told they are on an antipsychotic has been given accurate information that conveys something completely false about their situation.

The useful question to ask a prescriber is therefore never what class a drug belongs to. It is: what are you treating with this, and at what dose.

💚 Antidepressants, mostly not for depression

These are the most widely prescribed psychiatric medicines and a substantial share of prescriptions are for something else.

The SSRI group — sertraline, escitalopram, fluoxetine, paroxetine, citalopram — is first-line not only for depression but for generalised anxiety, panic disorder, obsessive compulsive disorder, social anxiety and post-traumatic stress. In anxiety they are more effective than anything else available long term.

The SNRI group — venlafaxine, duloxetine — adds noradrenaline. Duloxetine is separately licensed for diabetic nerve pain, for fibromyalgia and for stress incontinence, and is prescribed for those in people with no mood problem whatever.

The tricyclics are now used more for pain than for depression. Amitriptyline at ten to fifty milligrams — a fraction of the antidepressant dose — is standard for nerve pain, migraine prevention and sleep. At that dose it is not treating depression and was never intended to.

Trazodone is the most striking case. Classed as an antidepressant, it is prescribed overwhelmingly at low doses for insomnia, where its sedating action is the point and the antidepressant effect is not being sought at all. It is a reasonable option where a sedating agent is wanted without the dependence of a benzodiazepine, and it is worth knowing that the evidence for it in insomnia is moderate rather than strong, and that it can cause dizziness on standing.

🧊 Antipsychotics, mostly not for psychosis

The name alarms people more than any other, and the majority of prescriptions are not for schizophrenia.

They are central to bipolar disorder, in mania and in bipolar depression and in long-term prevention. Several are licensed as an addition to an antidepressant where that alone has not worked, at doses well below antipsychotic levels. One is standard for nausea in cancer treatment. Several are used for severe irritability and aggression in autism and in dementia, and at low dose for sleep and anxiety.

What they share is a cost that needs watching. Metabolic effects — weight gain, raised blood sugar and lipids — vary considerably between them and are the main long-term problem, requiring weight, waist, glucose and lipid checks rather than being discovered years later. Movement effects range from restlessness through stiffness and tremor to, with long use, involuntary movements that may not fully reverse. And raised prolactin causes breast changes and menstrual disruption.

None of that argues against them where they are indicated. It argues for knowing what is being monitored and making sure it is.

⚡ Anticonvulsants doing three jobs

Drugs developed to prevent seizures turned out to stabilise mood and to quieten damaged nerves, and most of their prescriptions are now for those.

Valproate, lamotrigine and carbamazepine are core treatments in bipolar disorder. Gabapentin and pregabalin are used for nerve pain and for anxiety, and despite their names have nothing to do with the GABA system.

Two of these carry warnings that override everything else about them.

Valproate must not be taken by anyone who could become pregnant unless there is no alternative and formal conditions are met, because exposure in pregnancy causes physical malformations in around one in ten and neurodevelopmental problems in a substantially higher proportion.

Lamotrigine must be increased very slowly, because rapid increases raise the risk of a rare but serious skin reaction. Any rash while starting or increasing it means stopping and seeking advice the same day.

⏳ How long each takes

Expectation determines whether treatment survives long enough to work, and this is the single most useful table in the article.

Two consequences follow. The slow ones are abandoned before they work — four weeks is the commonest point at which people stop, which is just before the point at which benefit appears. And the side effects of the slow ones arrive in the first days while the benefit arrives weeks later, so the early period offers all of the cost and none of the return. Knowing that in advance is most of what gets people through it.

🛑 Three different things called the same word

Fear of dependence prevents a great deal of appropriate treatment, and it usually rests on collapsing three distinct phenomena into one.

Discontinuation symptoms

What happens on stopping an antidepressant abruptly: dizziness, brief electric-shock sensations, nausea, irritability, vivid dreams, flu-like aching. Unpleasant, self-limiting, worse with the shorter-acting drugs, and prevented by tapering. There is no craving, no escalation of dose, no compulsion. It is the body readjusting.

Physical dependence and withdrawal

What happens with benzodiazepines and sleeping tablets: the body has adapted, tolerance has developed, and abrupt cessation can produce severe symptoms including, after prolonged use, seizures. It develops in anyone taking them long enough, including people taking exactly what was prescribed.

Addiction

Compulsive use despite harm, escalating doses, obtaining supplies elsewhere. A different situation again, and a much less common one.

The practical distinction: antidepressants and antipsychotics do not cause addiction, though they do need tapering. Benzodiazepines and stimulants are controlled substances and need managing accordingly. Conflating the two groups leads people to refuse the safe ones and to accept the risky ones as harmless.

📊 What should be monitored

Frequently arranged badly and worth asking about directly.

• Antipsychotics — weight and waist, glucose, lipids, prolactin, and for some a heart tracing
• Lithium — blood levels, kidney function, thyroid and calcium, indefinitely
• Valproate — liver function and blood count, plus the pregnancy prevention requirements
• Clozapine — mandatory regular blood counts, without exception, because of a specific risk to white cells
• Stimulants — blood pressure and pulse, and height and weight in children
• Antidepressants — sodium in older people, and mood in the first weeks of treatment in the young

A reasonable question at the start of any of these is simply: what needs checking, and how often. If the answer is vague, it may not have been arranged.

🔗 Combinations that matter

Alcohol adds to sedation across every class and worsens mood over time regardless of what is being taken for it.

Several serotonin-raising drugs together can produce serotonin syndrome — agitation, sweating, shivering, tremor, twitching and fever over hours. Tramadol is the commonest unexpected culprit, since it is prescribed as an ordinary painkiller.

Benzodiazepines with opioids multiply the suppression of breathing rather than adding to it, and account for a large share of overdose deaths.

St John’s wort, bought freely, raises serotonin and simultaneously speeds the clearance of a long list of medicines including hormonal contraception.

Modafinil and several anticonvulsants reduce the effectiveness of hormonal contraception, which is regularly missed.

Anticholinergic medicines — some antipsychotics, the tricyclics, older antihistamines — accumulate a burden that impairs memory and attention, and a person can easily be taking three without anyone counting.

🚨 What means stop and seek help

Rare across all these classes, and worth recognising.

Any rash while starting or increasing lamotrigine, or on any new medicine.

High fever with muscle rigidity and confusion on an antipsychotic — a rare and serious reaction requiring emergency care.

Agitation, sweating, shivering and fever over hours after adding a serotonin-raising drug.

Coarse tremor, vomiting, unsteadiness and confusion on lithium.

Fever, sore throat or mouth ulcers on clozapine — same day, without waiting.

A prolonged painful erection on trazodone — emergency.

New or worsening thoughts of self-harm after starting anything, particularly in the first weeks and particularly in young people.

📋 Questions worth asking

What are you treating with this? Not what class it is. The answer to that question is what actually applies to you.

How long before I know whether it works? So you do not stop at four weeks on something that takes six.

What will I feel in the first fortnight? The early period is usually the worst of it.

What needs monitoring? And has it been arranged.

How will we stop it, when the time comes? Asked at the start, which prevents an abrupt stop later.

Is it a controlled substance? A short list, and it changes what to expect.

Treatment across these classes is stocked in the antidepressant, antipsychotic, anti-anxiety, anticonvulsant, ADHD and sleep aid categories — including Desyrel (trazodone), which is the clearest illustration of everything above: an antidepressant by classification, prescribed overwhelmingly for something else.

❓ Frequently asked questions

📑 Sources and editorial

• Historical accounts of the discovery and naming of the first antidepressants and antipsychotics
• Receptor occupancy studies of quetiapine across the dose range
• Licensing information for duloxetine in diabetic neuropathy, fibromyalgia and stress incontinence
• Evidence for low-dose tricyclics in neuropathic pain and migraine prophylaxis
• Reviews of trazodone for insomnia, and reports of priapism
• Guidance on antidepressant discontinuation symptoms and tapering
• Literature distinguishing physical dependence, discontinuation and addiction
• Monitoring requirements for antipsychotics, lithium, valproate, clozapine and stimulants
• Regulatory requirements for valproate use in those of childbearing potential
• Guidance on serotonin syndrome and on neuroleptic malignant syndrome
• Related reading: how these drugs act on neurotransmitters, benzodiazepines, bipolar disorder
• Related products: antidepressant category
• RXshop Editorial Team — reviewed by Thomas Walsh, MD, Psychiatrist and Mental Health Specialist