Tricyclic and some other classes of antidepressants as well as antipsychotics have long been used for the treatment of insomnia, whereas selective serotonin reuptake inhibitors (SSRIs) generally disrupt sleep early in a course of treatment. This effect of SSRIs on alertness can be offset by sedative antidepressants such as trazodone, probably because they block 5-HT2 receptors which are being overstimulated by an increase in 5-HT (Kaynak et al, 2004). Other 5-HT2 antagonist antidepressants such as nefazodone (Hicks et al, 2002) and mirtazapine (Winokur et al, 2003) have been shown to reduce insomnia in depression, especially early in treatment. There are no controlled studies of the hypnotic efficacy of low-dose amitriptyline but despite this it is fairly common in primary care practice to use 10 or 25 mg amitriptyline to promote sleep. At this dose amitriptyline is probably acting mostly as a histamine H1 receptor antagonist, although a degree of 5-HT2 and cholinergic muscarinic antagonism may also contribute.