Insomnia can be transient (<2 weeks), short-term (2–4 weeks), or chronic (>4 weeks).1 Transient or short-term insomnia is often related to situational, environmental, or temporary medical stresses. In such cases, if the cause of stress can be relieved, or the medication withdrawn, then the insomnia may also resolve. If withdrawal of medication is not practical, then dose titration is often necessary to achieve an acceptable benefit: side-effect ratio.
Transient situational insomnia may initiate cognitive–behavioural processes (i.e., anxiety about getting to sleep), which may lead to chronic insomnia, even when the stress factor is eliminated. Chronic/persistent insomnia may be caused by a primary sleep disorder, or be secondary to another condition/situation, e.g., as a result of a psychiatric disorder. If the insomnia is found to be a secondary effect of another medical disorder, then initial treatment is often focussed on resolving the primary condition, in order to simultaneously relieve the secondary symptoms of insomnia.
Reference:
1. National Institute of Mental Health. Consensus conference report: drugs and insomnia –the use of medication to promote sleep. JAMA 1984; 251: 2410–2414.