07 - Summary

Summary

Other substances CHAPTER 12 Mood disorders ■ ■Caffeine may elevate mood through increasing noradrenaline release34 and modest caffeine consumption may protect against depression in those who do not have a pre-­ existing mood disorder.35 ■ ■People with mood disorders are more likely to consume caffeine, particularly when depressed.16,36 ■ ■Depressed patients may be more sensitive to the anxiogenic effects of caffeine.37,38 ■ ■Excessive consumption of caffeine may precipitate mania.38,39 ■ ■Caffeine can increase cortisol secretion (gives a false positive in the dexamethasone-­ suppression test),40 increase seizure length during electroconvulsive therapy41 and increase the clearance of lithium by promoting diuresis.42 Anxiety disorders ■ ■Caffeine increases vigilance, decreases reaction times, increases sleep latency and worsens sleep quality; effects that may be more marked in poor metabolisers. ■ ■May precipitate or worsen generalised anxiety and panic attacks;43 vulnerability to these effects may be genetically determined.11 ■ ■Effects are so marked that caffeine intoxication should always be considered when patients complain of anxiety symptoms or insomnia. ■ ■Symptoms may diminish considerably or even abate completely if caffeine is avoided.44 ■ ■Patients with panic disorder consume much more caffeine than controls45 but the reasons for this are not clear. Greater consumption triggers panic attacks in those with panic disorder but not in other populations.46 Other disorders Weak evidence supports the benefit of caffeine in attention deficit hyperactivity ­disorder (ADHD)47 and that high caffeine consumption may protect against late-­life cognitive decline.48 Summary ■ ■Caffeine is present in high quantities in coffee and some soft drinks, particularly energy drinks. ■ ■The intake of caffeine may worsen psychosis and anxiety. Young people may be particularly vulnerable. ■ ■Caffeine inhibits clozapine metabolism. ■ ■Caffeine intoxication is characterised by psychomotor agitation and rambling speech. ■ ■Caffeine may be associated with toxicity when co-­administered with CYP1A2 inhibitors such as fluvoxamine. ■ ■Caffeine can enhance the reinforcing effects of nicotine and possibly other drugs of misuse.