Fixing appointments with the López family can be tricky. "Come round at midday," says David López, when I speak to him on the telephone. "If you are lucky we will all be awake." They are not.
"This place is getting to be like a hospital ward," says David as he squeezes his considerable bulk into a chair in their spacious but drab sitting room. The family's long, narrow Madrid apartment is a tunnel of doziness. Even at midday only a dribble of daylight enters, adding to the sensation of semi-wakefulness. Our conversation is accompanied by a symphony of yawning, eye-rubbing, occasional drifts into semi-slumber and sudden jolts upright as David, Miguel Angel and Julián snap back – or simply panic that they may have missed something.
They do not want to seem impolite. The López clan is the first-known example of an extended family of sufferers in the world. Rosa Peraita-Adrados, the Madrid doctor whose dogged detective work tracked down the disconnected branches of a unique family that was fractured by Spain's bloody civil war, believes they could help to find a cure for one of the most puzzling of conditions. Their genes have already provided some of the strongest clues yet about what might be causing this strange and incapacitating sleep disorder.
Doctors once thought of narcolepsy and cataplexy as separate illnesses. The former provokes irresistible bouts of sleep; the latter is a momentary muscular collapse provoked by sudden emotions or laughter. Now it is clear the two things usually go together. David admits to often nodding off halfway through a task. He is so afraid of dropping dishes that he hugs them closely to his chest and walks very slowly to the dinner table.
Laughter, he points out, is one of their worst enemies, as it provokes bouts of cataplexy. Narcolepsy and cataplexy were both first described in the 1880s – and even then the first case of the latter, discovered by German doctor Carl Westphal, was a family problem, shared by a mother and son. About one in 5,000 people are thought to suffer from a condition whose prevalence varies across the globe, with some 12,000 in Britain alone. Living with the illness can be tough. Sufferers struggle to stay either awake or asleep for a sustained period of time. Luckily for me, the Lópezes are enjoying our chat. "
"Above all what you feel is fear, panic and sometimes you even experience your own death. It is like starring in your own horror film." Julián's cousin Jesús – another of Peraita-Adrados's patients – battles with everything from monsters to gypsy gangs, thrashing his limbs around in action-packed fights. But not all the dreaming in the house is bad. Sometimes euphoria strikes instead. "I have found my father chuckling loudly to himself in his sleep," says David. "Sometimes I too have woken up laughing myself silly. It all depends on your mood."