Brit. J. Psychiat. (I976), 529, 472—5

Seasonal

Patterns of Suicide, Depression Electroconvulsive Therapy By M. R. EASTWOOD

Summary. tions

This study

for suicide,

hospital

examined

and J. PEACOCKE

the hypothesis

admissions

and

that there

for depressive

illnesses

are seasonal

and

varia

electroconvulsive

therapy and that these are inter-related. It was found that the seasonal variations did coincide, with peaks occurring in the Ontario spring and autumn. The importance of depression as a cause of suicide and the effect of electroconvulsive therapy upon the suicide rate are discussed.

Davies(1973)discovered no seasonalvariation

INTRODUCTION

The seasonalnatureof suicidehas been re cognized since the time of Durkheim (1897). Thus, Dublin (1963)noted a springpeak for suicidefor severalcountriesin Europe, the USA and Japan and an additionalautumn peak in the USA. Lester (1971) found peaks in May and October in upstate New York, in contrast to deaths from all other causes which had the highest rates in December. Depressive illnesses are often thought to have a seasonal variation, popularly assumed to be in the winter,

but

this is less well documented

than

in the

excretion

of catecholamines

and

Carney

et al (i@@) obtained inconclusive results in theirstudies ofmagnesium levels forpsychiatric diagnoses

at different

times

of the

year.

The

prescription of electroconvulsive therapy (ECT),

which has been suggestedas the treatmentof choice for endogenous also seems

to vary

depression during

(d'Elia,

the year

1975),

(Eastwood

and Peacocke,1975). It was hypothesized that there are seasonal variations for suicide, hospital admissions for depressive illnesses and electroconvulsive

that of suicide. Zung (i@i@,)and Kraines (i@@7), in the USA, both showed that hospital admissions for depression had a non-significant tendency to peak in March/April, and Kraines furtherfound a statistically significant peak in

therapy,

shown

(295 . 7),

and that these are inter-related. METHOD

The admissiondate and dischargediagnosis for all psychiatric admissionsto provincial September. In Germany, Faust (i@7@) showed in-patient facilities were obtained from the that hospital patients with schizophrenia and OntarioMinistryofHealthfortheperiod1969 endogenous depression were admitted in ‘¿warm' to 1973 inclusive. The principaldiagnoses weather, while those with neurotic depression examined were the depressive psychoses (296 and did not have this seasonal variation. Hospital 2g8@o) and depressive neurosis (@[email protected])@ Other diagnoses studied were schizo-affective disorders studies from the southern United States have during

an

the

increase

summer

in

psychiatric

months

admissions

(Cerbus

other

schizophrenias

(295)

and

the

and

neuroses other than depressive neurosis (300). Dallara, 1975; Cerbus, 1970). The studies cited The admissions for these diagnoses and the for Ontario (suppliedby Stat tendeithertobe unclearin defining depression suicidefigures

or to be on a small scale. Community data are meagre, although Kellner (1966) found no seasonal variation in the frequency of neurosis

istics Canada)

seen by general

fiveyearsof the studythe averagenumber of

practitioners.

More indirectly, 472

were examined

by month

for the

five-year period. The province

of Ontario

has

a population

and during

the

of over 8,ooo,ooo

M. R. EASTWOOD

admissions

to Ontario

psychiatric

facilities

AND

was

6000

approximately 43,000. The ECT data, which were not available for the province, were obtained from three Toronto hospitals; a post graduate hospital

473

J. PEACOCKE

5900

psychiatric institute, a city mental and a psychiatric unit of a general

5800

hospital. These facilities together had approxim ately 750 beds, with 4,000 admissions a year 5700

during the study period. Since there was con sistency for the five years for suicide, depression

and ECT, the following results are expressed as averages for each month. RESULTS

@ @

5500

Suicide The seasonal variation forsuicide isshown in Figure @.The peaks for males are in May and Octoberand forfemalesinMarch and October but are significantly different from a uniform distribution formales only (P