The paper examines the nature of causality and how the concept can be interpreted and used in epidemiological psychiatry. The relationship of causality to logical relations is reiterated, and it is emphasized that these relationships in their pure form cannot apply to any one cause of an effect which is the outcome of several causes. In such a case the relation of the cause to the effect is one of weak implication. The fact of weak implication opens the door to the construction of certain causal models, and the possibilities afforded by this situation are illustrated by reference to the work of Brown et al (1975). Weak implication may be an intransitive relationship, and this is shown to invalidate certain ways of testing such models and the conclusions which arise from them.

The relationship between life events and the onset of organic physical illness has been studied in a group of women in the general population. The link between severe events and the onset of organic illness, which held only for women of 50 years or younger, was not a direct causal association but mediated by an intervening psychiatric disturbance of an affective kind, all occurring within a six month period. The findings are discussed in the light of the high psychiatric morbidity found in physically ill patients.

A 20 per cent prevalence of mild clinical depression was found in 120 women assessed at about six weeks postpartum. The strongest associated factor was occurrence of recent stressful life events. Previous history of psychiatric disorder, younger age, early postpartum blues, and a group of variables reflecting poor marital relationship and absence of social support were also notable. Poor marital support acted as a vulnerability factor, only producing an effect in presence of stressful life events. Previous psychiatric history produced a strong independent effect, both with and without life events. Postpartum blues were only associated with depression in the absence of life events, suggesting a small hormonal sub-group. Overall the findings indicate the importance of social stress in puerperal depression.

Information about perceptions of labour and delivery and about immediate emotional reactions to their newborn babies was obtained from two groups of primiparous women (n = 112 and n = 41) and from 40 multiparae. About 40 per cent of primiparae and 25 per cent of multiparae recalled that their predominant emotional reaction when holding their babies for the very first time had been one of indifference. Maternal affection was more likely to be lacking after delivery if the mother had had a forewater amniotomy and had, in addition, either experienced a painful and unpleasant labour or been given more than 125 mg of pethidine.

Most mothers developed affection for their babies within a week of delivery and, in all groups of subjects, no longer term adverse effects were seen, such as post-natal depression or aggressive impulses directed at the baby. Three months post-natally it was, however, found that a mother was more likely to express feelings of dislike or indifference towards her baby if she was clinically depressed at the time.

A controlled study comparing salbutamol (6 mg/day) to clomipramine (150 mg/day), both given by intravenous infusion, was performed on depressed inpatients (10 per group). The symptomatology was evaluated by two blind observers at days 0, 5 and 15 using the Hamilton Rating Scale. Both treatments were effective on the overall symptomatology but the onset of action of salbutamol was more rapid.

Sixty patients, 30 with depressive neurosis, 15 with anxiety neurosis and 15 with phobic anxiety states, were treated with the monoamine oxidase inhibitor, phenelzine, in two different dosage schedules for four weeks. All patients received an initial dose of 15 mg daily, increasing to 30 mg daily between the third and seventh day, but subsequently, using double-blind procedure, one group took the commonly prescribed dose of 45 mg daily and the other took 90 mg daily. Acetylator status was independently determined before the start of treatment. Each diagnostic group showed a similar response to treatment, but patients taking the higher dose improved significantly more than those taking normal dosage, and the rate of improvement, measured by weekly self-ratings, was also more rapid with higher dosage. Acetylator status did not affect clinical response. The results suggest that dosage is more important in determining clinical response to phenelzine in neurotic disorder than specific diagnosis or acetylator status.

In 60 physically and mentally healthy human subjects, lumbar cerebrospinal fluid was analysed by mass fragmentography for 5-HIAA, HVA and MOPEG. Individuals with a family history of psychiatric morbidity had significantly greater variation in monoamine metabolite concentrations than subjects without such a family history. In subjects with a family history of schizophrenic psychosis 5-HIAA and HVA concentrations were significantly higher than in subjects with depressive disorders within the family. For subjects with deviant 5-HIAA levels the probability of having a psychiatric family history was 2.7 times higher than in subjects with normal values. For HVA and MOPEG similar relationships, but of a lower significance level, were found. The results suggest that the cerebral monoaminergic transmitter amines play critical roles in the pathophysiology of psychotic and depressive disorders with a family disposition. They also indicate a value of monoamine metabolite determination in CSF for the prediction of family vulnerability for psychiatric morbidity in healthy subjects.

Handedness was assessed in 272 schizophrenics and compared with findings in normal controls. The schizophrenics differed significantly from the normal controls in their handedness patterns, having a higher proportion of fully right-handed subjects. Findings in brain-damaged and elderly schizophrenic patients are also reported. The lack of consistency of reporting of handedness in schizophrenic populations in previous studies is discussed. While it is probable that differences in the methods of study of handedness account for some of the variance, differences in the type of schizophrenic illness seem likely to be of greater importance.

Five hundred and ten patients receiving long-term in-patient care for schizophrenia were examined in terms of their current mental state, cognitive functioning, neurological status and behavioural performance. The abnormalities of these areas of their present state were related to historical factors, personal details, the features of the illness at its worst and physical treatment received. Significant associations between the present state and historical factors were few and mainly concerned time and the features of the illness at its worst. Current abnormalities were not related to past physical treatment, but highly significant correlations were found between the impairments of the four areas of the present state. It is concluded that these impairments are likely to be an integral part of the disease.

One hundred consecutive referrals have been surveyed, the diagnostic and behavioural problems leading to referral considered and follow-up information obtained one year later. For most admission to hospital as in- or day-patients was unnecessary. Old people's homes do not make excessive demands on the psychiatric services, but deserve support, including help in developing a more tolerant and flexible approach to less conforming residents. This is becoming imperative now that old people's homes are dealing with increased numbers of disturbed residents.

Twenty patients with the diagnosis hysterical personality disorder were compared with a matched control group of patients with other personality and neurotic diagnoses. Subjects' moods were assessed with a visual analogue scale 4 times a day for 5 consecutive days. Patients with a primary discharge diagnosis of hysterical personality disorder showed greater variability of mood than controls. Since emotional lability is said to be a characteristic hysterical trait, the results are taken as empirical support for the validity of one of the clinical judgements inherent in the diagnostic process.