44 - Incidence and severity

Incidence and severity

Depression and anxiety disorders CHAPTER 3 Antidepressant withdrawal symptoms Signs and symptoms Antidepressant withdrawal symptoms may be entirely new or similar to some of the original symptoms of the illness for which the medication was originally given. Withdrawal symptoms can be distinguished from a relapse or reoccurrence of the underlying disorder by their rapid onset (days, rather than weeks, or within three to five half-­lives of the drug),1 the rapid response to reintroduction of the antidepressant (generally within hours, certainly within days), and the presence of somatic and psychological symptoms distinct from the original illness (e.g. brain zaps, dizziness, nausea).2 The wide variety of symptoms reported with SSRIs and related drugs is summarised in Figure 3.2. Symptoms reported with other antidepressants are summarised in Table 3.8. Incidence and severity Antidepressant withdrawal/discontinuation symptoms occur in many patients (Box 3.1). Incidence rates from 14 studies that examined antidepressant withdrawal ranged from 27% to 86%, with a weighted average of 56%.3 Although reported incidence rates vary widely between studies of different drugs and methodologies (9% to 77% for fluoxetine, and from 42% to 100% with paroxetine),3 symptoms are seen to some extent with all antidepressants, with the possible exception of agomelatine.1 Two meta-­ analyses published in 2024  gave strikingly different estimates of withdrawal incidence.4,5 Sensory symptoms Paresthesia Numbness ‘Shock-like’ or ‘electric zap’ sensations in head or limbs Rushing noises Palinopsia (visual trails) Hyperacusis Unusual taste/smell/visual sensations General somatic symptoms Flu-like symptoms Lethargy/fatigue Headache Tremor Sweating Anorexia Weakness Techycardia Muscle aches/pains Shaking/trembling Affective symptoms Irritability Anxiety/agitation Low mood/depression Tearfulness Dread Panic attacks SSRI withdrawal syndrome Disequilibrium Dizziness (most common) Light-headedness Vertigo Ataxia Gait instability Sleep disturbance Insomnia Nightmares Excessive dreaming Gastrointestinal symptoms Nausea Vomiting Diarrhoea Anorexia Sexual Genital hypersensitivity Premature ejaculation Cognitive Confusion Decreased concentration Amnesia Depersonalisation De-realisation Figure 3.2  Common withdrawal symptoms with SSRIs and similar drugs.