Antidepressants and Anxiety Medicines: What to Expect When You Start

A practical guide to how these medicines work, when improvement starts, common side effects, stopping safely and when to seek help

Starting a medicine for depression or anxiety can feel like a big decision.

People often worry about:

• becoming dependent;
• feeling emotionally numb;
• weight gain;
• sexual side effects;
• whether the medicine will change their personality;
• whether they will ever be able to stop.

Another common concern is:

“What if I feel worse before I feel better?”

That can happen.

Antidepressants often take weeks rather than days to produce their full benefit, while some side effects can appear much earlier.

The practical question is:

“Is this medicine helping you feel and function better, with side effects you can live with?”

What are antidepressants?

Antidepressants are medicines used to treat conditions including:

• depression;
• generalised anxiety disorder;
• panic disorder;
• social anxiety disorder;
• obsessive compulsive disorder;
• some other mental-health conditions.

Despite the name, many antidepressants are commonly used to treat anxiety even when the person is not depressed.

Common groups include:

• SSRIs — selective serotonin reuptake inhibitors;
• SNRIs — serotonin-noradrenaline reuptake inhibitors;
• other antidepressants such as mirtazapine;
• older classes used in selected situations.

For many people with depression or anxiety, an SSRI or SNRI is a common starting option.

What should successful treatment actually improve?

Try to identify the problems you want treatment to change.

For depression, that might include:

• getting out of bed more easily;
• enjoying things again;
• improved concentration;
• less hopelessness;
• better energy;
• functioning better at work or home.

For anxiety, it might mean:

• worrying less;
• fewer panic attacks;
• less avoidance;
• sleeping better;
• being able to drive, work, shop or socialise more normally;
• feeling less physically tense.

The important question is not:

“Can I feel the tablet?”

It is:

“Is my life becoming easier to manage?”

How long do antidepressants take to work?

They usually do not work immediately.

For depression, some improvement may begin after around 2–4 weeks, with fuller benefit often taking 6–8 weeks.

For anxiety disorders, improvement may take 4–6 weeks, and sometimes longer.

The first changes may be subtle.

You may notice:

• sleeping slightly better;
• getting out of bed more reliably;
• concentrating for longer;
• crying less often;
• worrying for fewer hours of the day;
• returning to activities you had stopped;
• panic attacks becoming less frequent.

Feeling somewhat better after a week can be encouraging, but it does not necessarily mean the medicine has reached its full effect.

Treatment reviews should therefore look at function, not just ask:

“Do you feel better?”

Can anxiety get worse when I first start?

Yes.

Some people feel temporarily more:

• anxious;
• restless;
• jittery;
• nauseated;
• unable to sleep

after starting an SSRI or SNRI.

This does not automatically mean the medicine is wrong.

But if the increase in anxiety is severe, persistent or feels unsafe, contact the prescriber rather than simply pushing through it.

What are the common side effects?

Side effects vary between medicines.

Common possibilities include:

• nausea;
• headache;
• dizziness;
• dry mouth;
• sweating;
• sleep disturbance;
• tiredness;
• restlessness;
• appetite or weight changes;
• sexual problems.

Some improve during the first few weeks.

Others may require:

• changing the dose;
• changing the timing;
• switching medicines;
• reconsidering whether the benefit outweighs the side effects.

What about sexual side effects?

This deserves to be discussed openly.

SSRIs and SNRIs can cause:

• reduced libido;
• difficulty becoming aroused;
• delayed orgasm;
• inability to orgasm;
• erectile difficulties.

These effects can be clinically significant.

Australian product warnings now recognise reports that sexual dysfunction can persist after an SSRI or SNRI has been stopped, although this appears uncommon and the true frequency is not known.

That does not mean everyone should avoid antidepressants.

It means sexual side effects should be part of informed treatment decisions, rather than something patients discover by accident.

If this happens, tell your GP.

There may be alternatives.

Will antidepressants make me emotionally numb or change my personality?

Some people describe feeling:

• emotionally flatter;
• less able to cry;
• less affected by positive or negative events;
• unlike themselves.

For some, reducing overwhelming emotional intensity is helpful.

For others, it feels like too much.

The goal should not be:

“I don’t feel anything anymore.”

If treatment works well, many people feel more like themselves because depression or anxiety is no longer dominating their thinking.

But if you feel unusually detached, agitated or emotionally flat, the treatment should be reviewed.

What about weight gain?

Some antidepressants are more likely than others to affect appetite or weight.

Mirtazapine, for example, commonly causes:

• increased appetite;
• weight gain;
• drowsiness.

Weight change should be discussed rather than assumed to be unavoidable.

Sometimes changing:

• medicine;
• dose;
• eating pattern;
• activity

can help.

The choice of antidepressant can also take your baseline concerns into account.

What about sleep?

Different antidepressants affect sleep differently.

Some people feel:

• activated;
• restless;
• unable to sleep.

Others become:

• tired;
• sleepy.

This can influence which medicine is chosen and when it is taken.

A more sedating medicine may sometimes help when insomnia is a major problem, but excessive daytime sedation can make a medicine unsuitable for someone who drives or operates machinery.

What if I feel much more energetic but still very depressed?

This deserves attention.

Occasionally energy or activation improves before hopelessness has fully lifted.

That may temporarily give someone more ability to act while they are still having suicidal thoughts.

Early review therefore matters, particularly when:

• depression is severe;
• suicidal thoughts are already present;
• the person is younger;
• the dose has recently changed.

Can antidepressants cause suicidal thoughts?

Most people do not develop suicidal thoughts because of antidepressants.

However, worsening depression, agitation or emerging suicidal thoughts can occur, particularly early in treatment or after dose changes.

Seek prompt medical review if there is:

• new suicidal thinking;
• rapidly worsening depression;
• severe agitation;
• unusual behavioural change.

If you or someone else is in immediate danger, call 000.

What about bipolar disorder?

This is important.

Someone who is depressed may actually have a bipolar-spectrum illness, where episodes of depression occur alongside episodes of mania or hypomania.

Before starting an antidepressant, tell your doctor if you have ever had periods of:

• needing very little sleep without feeling tired;
• unusually elevated or irritable mood;
• racing thoughts;
• excessive confidence;
• impulsive spending or risk-taking;
• unusually rapid speech or activity.

Bipolar disorder has a different treatment approach and often requires mood-stabilising treatment rather than simply treating depressive symptoms in isolation.

What are “anxiety medicines”?

This phrase can mean different things.

Some medicines treat the underlying anxiety disorder over time.

Others provide rapid short-term relief.

Antidepressants

SSRIs and SNRIs can treat anxiety over weeks and months.

They are not immediate calming medicines.

Benzodiazepines

Medicines such as diazepam can relieve anxiety relatively quickly.

But they carry important risks, including:

• sedation;
• impaired coordination;
• memory problems;
• tolerance;
• dependence;
• withdrawal.

That is why benzodiazepines are generally used cautiously and often for short periods rather than as indefinite treatment for anxiety.

Why are benzodiazepines different?

A benzodiazepine may make someone feel calmer within hours.

An antidepressant usually takes weeks to treat the underlying anxiety disorder.

That rapid effect is one reason benzodiazepines can feel very appealing.

It is also one reason they need to be used carefully.

With repeated use, the body can adapt.

This can lead to:

• tolerance;
• needing the medicine to feel normal;
• rebound anxiety when it wears off;
• withdrawal symptoms if stopped suddenly.

This does not mean everyone who takes a benzodiazepine briefly becomes dependent.

It means there should usually be a clear reason for:

• starting it;
• how often it is used;
• how long it will continue.

Alcohol also matters because combining it with sedating medicines can worsen:

• drowsiness;
• coordination;
• judgement;
• safety.

Can I stop a benzodiazepine suddenly?

Not after regular ongoing use.

Stopping abruptly after longer use can cause:

• rebound anxiety;
• agitation;
• insomnia;
• tremor;
• and, in severe cases, seizures.

If you have been taking a benzodiazepine regularly, ask your doctor about a gradual taper rather than stopping suddenly.

Do antidepressants cause addiction?

Not in the same way as benzodiazepines, alcohol or addictive drugs.

People generally do not:

• crave antidepressants;
• become intoxicated from them;
• compulsively seek escalating doses for a “high”.

But antidepressants can cause discontinuation symptoms if stopped too quickly.

That is not the same thing as addiction.

What happens if I stop an antidepressant suddenly?

Depending on the medicine, abrupt stopping may cause:

• dizziness;
• nausea;
• sleep disturbance;
• anxiety;
• irritability;
• unusual sensory symptoms;
• flu-like feelings;
• mood changes.

Some medicines are more prone to withdrawal symptoms than others.

Do not assume these symptoms automatically mean the depression or anxiety has returned.

Timing and pattern matter.

How should antidepressants be stopped?

Usually, gradually.

The exact taper depends on:

• which medicine;
• dose;
• how long you have taken it;
• previous withdrawal symptoms;
• why you are stopping.

Someone who has taken an antidepressant for years may need a much more gradual reduction than someone who has taken it briefly.

There is no universal taper that suits every patient.

How long should I stay on an antidepressant?

Treatment often continues beyond the point where you first feel better.

How long it should continue depends on:

• the severity of the illness;
• whether you have had previous episodes;
• relapse risk;
• how well the medicine is working;
• side effects;
• your preferences.

Longer treatment may be appropriate when there have been:

• recurrent depressive episodes;
• severe illness;
• repeated relapse after stopping;
• persistent anxiety disorders.

But repeat prescriptions should not continue automatically forever without review.

The decision to continue or taper should be individualised.

Does medication replace psychological therapy?

No.

Medication and psychological therapy do different things.

For many people, useful treatment can include:

• cognitive behavioural therapy;
• other psychological therapy;
• exercise;
• sleep improvement;
• reducing alcohol;
• addressing relationship or work stress;
• medication.

Medication may reduce symptoms enough to make psychological strategies easier to use.

For some people, therapy may be the main treatment.

For others, medication is very important.

What if the first antidepressant does not work?

That is not unusual.

First ask:

• Was it taken consistently?
• Was the dose appropriate?
• Was the trial long enough?
• Did symptoms improve at all?
• Were side effects limiting treatment?
• Is the diagnosis correct?

Possible next steps may include:

• adjusting the dose;
• switching antidepressants;
• changing medication class;
• adding psychological treatment;
• reassessing the diagnosis;
• seeking specialist advice in more complex or treatment-resistant illness.

One unsuccessful medicine does not mean depression or anxiety cannot be treated.

What should I review with my GP?

A useful medication review should ask:

• What symptoms were we treating?
• What has improved?
• What has not improved?
• How is sleep?
• How is anxiety?
• Are there sexual side effects?
• Has appetite or weight changed?
• Do I feel emotionally flat?
• Are there any suicidal thoughts?
• Am I taking the medicine consistently?
• Do we need to change the dose?
• Do I still need this medicine?

That is much more useful than simply:

“Any side effects? No? Here’s another script.”

When should I seek urgent help?

Seek urgent medical assessment if you develop:

• serious suicidal thoughts or plans;
• severe agitation or rapidly worsening mental state;
• manic symptoms;
• hallucinations or major behavioural change;
• a severe medication reaction;
• symptoms that make you or someone else unsafe.

For immediate danger, call 000.

A common misconception

MYTH: If antidepressants work, it means my depression or anxiety was caused by a chemical imbalance.

REALITY: Mental-health conditions are more complicated than one neurotransmitter being simply “too low”.

Antidepressants affect brain signalling, but response to medication does not prove a single biological cause.

Depression and anxiety can involve:

• biology;
• psychology;
• life circumstances;
• relationships;
• sleep;
• stress;
• physical health.

Treatment should reflect the whole person.

Another common misconception

MYTH: If I start an antidepressant, I will be on it forever.

REALITY: Not necessarily.

Some people benefit from long-term treatment.

Others use antidepressants for a period and later taper off.

Starting treatment is not a lifetime contract.

And one about anxiety tablets

MYTH: Diazepam works faster, so it must be a better anxiety medicine.

REALITY: Faster symptom relief does not automatically mean better long-term treatment.

Benzodiazepines can be useful in selected circumstances, but their rapid effect needs to be balanced against:

• sedation;
• tolerance;
• dependence;
• withdrawal.

The question I would ask

After a reasonable treatment period, I would ask:

“What can you do now that depression or anxiety was stopping you from doing before?”

Maybe the answer is:

• going back to work;
• seeing friends;
• driving again;
• sleeping normally;
• exercising;
• enjoying your children;
• no longer spending the whole day worrying.

That tells us more about treatment success than whether a questionnaire score moved by a few points.

The bottom line

Antidepressants can be very useful for depression and many anxiety disorders.

But they generally take weeks, not hours, to show their full benefit.

Early side effects may include:

• nausea;
• headache;
• sleep changes;
• anxiety or restlessness;
• sexual problems.

Some improve with time.

Others deserve a medication review.

Antidepressants are not the same as addictive sedative medicines, but they should usually be reduced gradually rather than stopped suddenly.

Benzodiazepines can relieve anxiety quickly but are generally best kept for selected short-term use because tolerance and dependence can develop.

The best question is not:

“Am I taking an antidepressant?”

It is:

“Is this treatment helping me get my life back?”

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