‘So when was John Lowther discharged from the unit?’

‘In April. He was in good spirits by then. He said he was going to tell everyone that he’d been away on holiday. Somewhere nice, like the Caribbean. Except that it couldn’t be the Caribbean, because he didn’t have a sun tan. I dare say his family didn’t let anyone know the truth either. That’s perfectly usual. There’s still a lot of stigma attached to mental illness, I’m afraid.’

‘He’d have to be on anti-psychotic drugs for some time, I imagine.’

‘Yes. But his records do show that he was worried about the side effects. Mr Lowther complained that he put on weight. And he twitched a lot, which he found distressing. Also, he said the medication made him impotent.’

‘He was very restless when we saw him last week.’

‘But no twitching?’

‘No.’

Sinclair fiddled with his glasses. ‘Mr Lowther was prescribed Orphenadrine for the side effects, but he didn’t like the idea of taking more tablets. So instead …’ He hesitated again.

‘You think he might have stopped taking his anti-psychotic drugs?’

‘Yes, it’s possible. Dealing with side effects is always a bit of a trade-off. It’s a question of striking the right balance for each individual. Mr Lowther said once or twice that the effects of the drugs were worse than a few harmless delusions. He thought he’d return to his old self if he stopped taking the medication – he’d become slimmer, stop twitching, regain sexual function. It’s a common response. Patients feel an overwhelming desire to go back to a time when they felt happy and safe.’

‘Hold on a minute – “a few harmless delusions”?’ said Cooper, picking out the most remarkable phrase in what he’d just heard.

Sinclair fixed him with a sad gaze from his pale eyes. ‘That would be the way it seemed to him, at this particular stage. I think Mr Lowther had probably forgotten the nature of his auditory hallucinations.’

‘How is it possible to forget something like that?’

‘It’s a normal function of the brain to filter out negative experiences and retain the positive ones. This applies to psychotic episodes as much as to anything else.’

‘I can’t see anything positive in what you’ve described, sir.’

‘Then I haven’t described it properly. The fact is, not everyone finds psychosis a negative experience. While some patients suffer persecutory or self-blaming delusions, others develop grandiose fantasies or have an experience of deep religious significance. This can appear very positive and life-affirming.’

‘Are you serious?’

‘Absolutely. I’ve known some individuals describe a psychotic episode as a revelation, a wonderful and exciting new way of seeing the world – in fact, the sort of experience that people seek from hallucinogenic drugs. You know, a surprisingly large percentage of the population have undergone a psychotic episode of some kind, without being disturbed by the experience. At the end of the day, a hallucination is merely the misattribution of internal events to an external source.’

Cooper shook his head, trying to throw off a sudden, unwelcome burst of insight, a glimpse of how it might feel if the reality of his own world became suspect. He was sure he would find it disturbing.

‘Could we get back to the question of John Lowther’s condition, and how he was being treated?’

‘Well, when Mr Lowther was discharged, he returned to the community. He has family members in Derbyshire. It’s normal practice to ensure that the family are fully aware of the importance of maintaining medication. We can’t be there standing over every patient personally, to make sure they take their drugs.’

‘Who was supposed to do that? His parents?’

Dr Sinclair frowned at the file. ‘According to his records, there’s a sister.’

‘She’s dead.’

‘Oh.’

‘And I think she might have been too preoccupied recently to worry about her brother.’

‘Mr Lowther must have been due for a review,’ said Sinclair. ‘Perhaps his GP had examined him recently.’

They looked at each other for a moment, conscious of the futility of trying to work out where and when the system had gone wrong.

‘Basically, a dangerous psychotic was allowed out into society unsupervised,’ said Cooper.

‘No, no, you don’t understand. Once a patient is discharged and living at home, clinicians are helpless. Even if we know they might be a risk to themselves and others, we can’t force an individual to continue medication. Not at present.’

‘But you’d like to be able to compel people to take their drugs?’

‘Detective Constable, fifty thousand patients are detained by psychiatrists every year. If we can’t compel people to continue medication when they’re back in the community, all that happens is that some of them get very ill again and have to be detained a second time, or a third. It just goes on and on.’

‘The revolving door approach. We see it often enough in the courts.’

‘I’m sure you do,’ said Sinclair. ‘Besides, John Lowther isn’t dangerous unless he has stopped taking his medication. And even then, he’s only a risk to himself. You say his sister died? The trauma of her death might have disrupted his normal routine anyway. It would be easy for him to slip. I hope he hasn’t gone beyond caring for himself.’

‘Doctor, if John Lowther’s psychotic episodes returned, would the hallucinations be as powerful as they were previously?’

‘Possibly more so. To be honest, in my next consultation with him, I might have been moving towards a conclusion that he was suffering from a treatment-resistant condition.’

‘What would you have done then?’

‘Tried another drug. Probably Clozapine.’ Sinclair took a tissue from a box on his desk and wiped a drop of sweat from his temple. ‘There’s one other thing that might be relevant …’

‘Go on, sir.’

‘At the time he was admitted to the unit, Mr Lowther was also suffering from night terrors.’

‘You mean nightmares?’

‘No, night terrors. Nightmares occur during REM sleep, terrors are experienced in stage four sleep. In practice, the distinction is that you remember nightmares, but you don’t remember terrors. They’re subconscious phenomena – but no less stressful, psychologically and emotionally.’

‘And those might have returned, too?’

‘It’s possible.’

‘In John Lowther’s case, would his deteriorating condition be noticeable in the way he talks?’

‘Yes, Mr Lowther suffers from thought disorder, another symptom of psychosis. It can lead the patient to speak quickly and incessantly, or to switch topic in mid-sentence. He could eventually become incoherent, using inappropriate words or mispronouncing them, or making up new words altogether.’

Cooper had been trying to make notes as the psychiatrist talked. But his pen paused, and he looked up.

‘Would you be willing to listen to a tape of an interview we conducted with Mr Lowther, and give us your opinion on it?’

‘Certainly, if you think it would help.’

‘How do you think John Lowther is likely to react in the present circumstances?’

‘It’s difficult to say. He’ll be in a rather unpredictable state. But one thing I’m sure of: he must be a very frightened man.’

‘Frightened of what? Of us?’

Sinclair smiled. ‘Hardly. At the moment, you’re the least of his problems.’

‘What, then?’

He put his glasses down and closed the file. Then he toyed with the items on his desk, teasing them into a more satisfactory arrangement.

‘Most of all, John Lowther will be frightened of himself,’ he said. ‘Of his own inner demons, if you like. Whatever form those demons might be taking.’

‘I don’t understand.’

‘I’m doing my best to explain. You see, Mr Lowther knows about the voices from past experience, though he’ll have tried to suppress the knowledge. If he’s off the medication, his auditory hallucinations will return. They might have returned already.’