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Communication of suicidal intent and suicide in unipolar depression
Journal of Affective Disorders, 1 (1979) 219-225 0 Elsevier/North-Holland Biomedical Press
COMMUNICATION OF SUICIDAL UNIPOLAR DEPRESSION A Forty
RICHARD
219
INTENT
AND SUICIDE
IN
Year Follow-Up
C. FOWLER
l, MING T. TSUANG
2 and ZIAD KRONFOL
*
t Veterans Administration Hospital and University of California, San Diego, School of Medicine, San Diego, CA 92161 and ’ University of Iowa College of Medicine, Iowa City, IA 52242 (U.S.A.)
SUMMARY Two hundred and 25 unipolar depressives hospitalized during the 1930’s were classified on the basis of documented communication of suicidal intent. A long term follow-up revealed 15 of the former patients had died by suicide. Communicated suicidal intent was documented in the index hospitel record of all 15. The presence of communicated intent may distinguish a group of unipolar depressives at risk for suicide from those not at risk.
INTRODUCTION
Depression remains the most frequently diagnosed psychiatric condition in cases of suicide (Barraclough et al. 1974). While psychiatric treatment has been successful in lowering the risk of suicide in depressive illness (Huston and Lecher 1948; Ziskind et al. 1945; Avery and Winokur 1976), there are depressives who suicide in spite of treatment (Barraclough et al. 1974) or never receive treatment. Suicide in the former group deserves particular scrutiny from the health professions because of the possibility of more successful therapeutic intervention. A necessary step for successful intervention is the accurate assessment of suicide risk. Psychiatrists have used various guidelines for identifying the suicidal depressive. Robins et al. (1959) have shown that it is the older male depressive who is a particular risk in America. In a British study Barraclough et aI.
Reprint CA 92131,
requests U.S.A.
to Dr. Fowler,
Veterans
Administration
Hospital
(116),
San Diego,
220
(1974) confirmed that the older depressive was a high risk but did not find a sex differential. The Barraclough et al. (1974) study also found a disproportionately high number of single and widowed individuals in depressives who had completed suicide. Unfortunately, the above variables are of limited help in assessing the suicide potential of the individual depressive because suicide occurs in all age and marital groups, as well as in both sexes. Factors that are closely associated with the act of suicide may be more helpful in assessing suicide potential in the individual depressive. The communication of suicidal intent, either by a direct statement or by indirect reference to death or suicide, is such a factor. The frequencies of such communication in the Robins et al. (1959) and Barraclough et al. (1974) studies are 68% and 58%, respectively. A prospective inquiry of those suicidal depressives seeking treatment, may yield an even higher rate of communicated intent. Thus, the communication or non-communication of intent may provide the psychiatrist with the means to determine whether an individual depressive is at risk for suicide. The present report tests this hypothesis on a population of hospitalized unipolar depressives. Two hundred and 25 unipolar depressives were divided into two groups according to the presence or absence or suicidal ideas and/or attempts. Forty year follow-up data provided the frequency of suicide in each group. METHODS
Previous reports have described the clinical, follow-up, and family data of 525 functional psychotics discharged from Iowa Psychopathic Hospital 40 years ago (Morrison et al. 1972, 1973; Winokur et al. 1972). These patients were selected according to the Washington University research criteria for psychiatric illness (Feighner et al. 1972) and included 225 unipolar depressives, the subjects of this report. The notation of suicidal ideas and/or attempts was previously determined. The basis for this determination was information from the record of the index hospitalization (Morrison et al. 1972). All patients who had no evidence of suicidal ideas during the index illness or made no suicide attempts at any time were placed in one group (NSIA) and all remaining depressives were placed in the other (SIA). This latter group included 64 patients with a history of one or more suicide attempts and 99 with suicidal ideas alone. The follow-up procedure, mortality rate (through December 31, 1974), and contribution of suicides and accidents to this mortality rate have been previously reported (Tsuang and Woolson 1977, 1978). A successful long term follow-up was accomplished on 221 (98%) of the depressives. Of these, 159 (74%) were deceased. The cause of death for each of the deceased was determined on the basis of information from death certificates and family members. Unnatural deaths with evidence of suicidal intent were classified as suicides. This was done without knowledge of the NSIA-SIA classification.
221
Statistical comparisons),
analysis of the catagorical unless otherwise noted.
data used the chi-square
test (2 X 2
RESULTS
There were 62 depressives who had not communicated suicidal intent and were therefore placed in the NSIA group. The remaining 163 depressives had communicated intent and thus comprised the SIA group. The demographic profile of these two groups (Table 1) indicates no differences regarding age, sex, education, marital status, and employment status. Similarly, a wide range of depressive and psychiatric symptoms did not differentiate the two groups. These included the following depressive symptoms: dysphoria, anorexia, weight loss, insomnia, loss of energy, agitation, psychomotor retardation, loss of interest, decreased libido, feelings of selfreproach or guilt, difficulty thinking, and diurnal variation. Psychotic symptoms included delusions, hallucinations, thought disorders, and catatonia. Identifiable precipitants and family history variables also failed to differentiate the two groups. The two groups were divergent, however, regarding the short term course. Information had been recorded in the medical record about the course subsequent as well as prior to the index hospitalization. This is summarized in Table 2. The NSIA patients were more likely to have had a psychiatric hospitalization prior to the index hospitalization, though there was only a trend toward more prior depressive episodes in this group. Data about the subsequent course indicates the NSIA group was less likely to have a subsequent depressive episode, though the initial recovery rates from the index episode were similar. There were no differences between the groups regarding chronicity or subsequent psychiatric hospitalization. Because of the intergroup difference regarding prior psychiatric hospitalization, the data analysis of subsequent course was limited to depressives whose index hospitalization occurred during the first depressive episode. The designation ‘first depressive episode’ was not synonymous with ‘first psy-
TABLE
1
DEMOGRAPHIC
PROFILE
OF UNIPOLAR
DEPRESSIVES NSIA N = 62 (%)
Age at onset of illness (X f SD) Age at index hospitalization (X * SD) Female Completed high school Married Employed
37 45 34 28 38 46
+ 14.19 f 12.95 (55) (45) (61) (75)
SIA N = 163 (%) 38 44 90 80 129 134
f 12.50 f 11.49 (55) (49) (76) (82)
P
NS NS NS NS NS NS
222 TABLE
2
COURSE OF UNIPOLAR DEPRESSION HOSPITALIZATION (BASED ON REVIEW
Prior depressive episode hospitalization Subsequent recovery without relapse recovered before subsequent no recovery outcome uncertain hospitalization
episode
PRIOR AND SUBSEQUENT OF HOSPITAL RECORD)
TO
INDEX
NSIA N = 62 (%)
SIA N = 163 (%)
P
31 (50) 16 (26)
66 (40) 21(13)
NS GO.02
25 (40)
50 39 34 40 29
NS GO.02 NS NS NS
6 (lo) 19 (31) 12 (19) 9 (15)
(31) (24) (21) (25) (18)
_
chiatric hospitalization’ as 6 (19%) of the 31 NSIA depressives and 12 (12%) of the 97 SIA depressives hospitalized during their first depressive episode had prior psychiatric hospitalizations (this intergroup difference is not significant). Table 3 summarizes the data about subsequent course for this subgroup of depressives. It indicates that the great majority of patients in both the NSIA and SIA groups initially recovered from the depressive episode; however, the SIA group continued to have a higher rate of subsequent relapse. The mortality data at the 40 year follow-up is summarized in Table 4. Over two-thirds of both groups were deceased at the time of follow-up. Of these, 15 patients were judged to have died by suicide. All 15 of the suicides were in the SIA group, a significant difference. Eleven of the suicides were in the SIA subgroup admitted during their first episode. When the analysis is limited to the depressives admitted during their first episode, the difference remains significant (Fishers exact test = 0.041, one-tailed).
TABLE
3
SUBSEQUENT SODE (BASED
COURSE FOR DEPRESSIVES HOSPITALIZED ON REVIEW OF HOSPITAL RECORD)
Recovery without relapse Recovered before subsequent No recovery Outcome uncertain Subsequent hospitalization
episode
DURING
FIRST
EPI-
NSIA N = 31 (%)
SIA N = 98 (%)
P
25 (81)
60 (62) 24 (25)
GO.05 GO.05 NS NS NS
2 4 6 7
(06) (13) (69) (23)
9 (09) 4 (94) 28 (29)
223 TABLE
4
MORTALITY
AT 40-YEAR
FOLLOW-UP
FOR
NSIA
SIA
Alive Suicide Non-suicide death No follow-up
13 (21%) O( 0%) 49 (79%) O( 0%)
45 15 99 4
Total
62
a Fisher Exact
Test, P = 0.0132,
UNIPOLAR
DEPRESSIVES
(28%) ( 9%)a (61%) ( 2%)
163 two-tailed
DISCUSSION
A comparison based on the presence or absence of communicated suicidal intent indicates similarities on demographic, symptom, and family illness variables for this population of unipolar depressives. The only observed differences concern the course of depressive illness both prior and subsequent to the index hospitalization. The excess of prior psychiatric hospitalization in the group defined by no communication of suicidal intent is paradoxical because suicidal ideas or attempts are a major reason for hospitalization of the depressive. There are, however, at least two possible explanations for this finding. The NSIA group could have more illness, either episodic or chronic, prior to the index hospitalization. We cannot fully assess this possibility because there was no recorded measure of chronicity for the period prior to the index hospitalization. However, the longer duration since the initial onset of illness (8 years vs 6 years in the SIA group) and the trend toward more episodes in this group provides some support for this explanation. Another possibility is that the difference in prior hospitalization is an artifact of the patients’ understanding of their illness. Although a patient’s perception could increase as well as decrease the likelihood of hospitalization, perceptions that decrease the likelihood are of particular concern because they can preclude necessary treatment. As an example there were patients in the SIA group who were hospitalized only after a serious suicide attempt prompted medical and psychiatric intervention. If these patients did not understand they were ill and in need of psychiatric care, they may have differed from patients in the NSIA group in their willingness to accept prior psychiatric treatment and hospitalization. Unfortunately, we did not have data available to assess such a possibility. The greater frequency of subsequent depressive episodes in the SIA group suggests that the risk of suicide increased with the number of depressive episodes. However, suicide and subsequent depressive episodes were not independently assessed in the original data collection. Consequently, depres-
224
sives who committed suicide during the short-term follow-up (the only interval in which subsequent depressive episodes were recorded) may have been coded as having a subsequent depressive episode even though the only known evidence of an episode was suicide. Therefore, it cannot be excluded from the present data that the risk of suicide increases with further depressive episodes. Nonetheless, the possible association of subsequent episodes and suicide provides hope for suicide prevention. In the Barraclough study (1972) of completed suicides, 69% of the cases with primary affective disorder had more than one episode and 33% met rigorous criteria for lithium prophylaxis. Consequently, minimizing the risk of further depressive episodes through lithium carbonate or other prophylactic therapies may have a major impact on the high suicide rate associated with depressive illness (Guze and Robins 1970). The absence of suicides in the NSIA group, is not comparable with other studies of completed suicide (Robins et al. 1959; Barraclough et al. 1974) because the latter are retrospective regarding the communication of suicidal intent. Therefore their finding that a minority of depressives do not communicate intent prior to suicide may reflect a methodological limitation of such studies. Only further prospective studies can assess the risk of suicide for depressives who do not communicate suicidal intent. There is an important need for such studies. Present treatment approaches may often proceed from the assumption that all unipolar depressives are at risk for suicide. This risk is one justification for the use of treatment modalities, especially antidepressant medication and electroconvulsive therapy, that in themselves carry risks. Although the risk of suicide is not the only indication for such therapies, psychiatrists use of such treatment modalities may be modified if it is established that some unipolar depressives are not at risk for suicide. The present study suggests that depressives who do not communicate suicidal intent are not at risk. Further investigation of this finding is warranted, however, before concluding that lack of communicated intent defines a group of depressives not at risk for suicide. REFERENCES Avery, D. and Winokur, G., Mortality in depressed patients treated with electroconvulsive therapy and antidepressants, Arch. Gen. Psychiat., 33 (1976) 1029-1037. Barraclough, B., Suicide prevention, recurrent affective disorder and lithium, Brit. J. Psychiat., 121 (1972) 391-392. Barraclough, B., Bunch, J., Nelson, B. and Sainsbury, P., A hundred cases of suicide Clinical aspects, Brit. J. Psychiat., 125 (1974) 355-373. Feighner, J.P., Robins, E., Guze, S.B., Woodruff, R.A., Winokur, H. and Munoz, R., Diagnostic criteria for use in psychiatric research, Arch. Gen. Psychiat., 26 (1972) 57-63. Guze, S.B. and Robins, E., Suicide and primary affective disorders, Brit. J. Psychiat., 117 (1970) 437-438. Huston, P.E. and Lecher, L.M., Manic-depressive psychosis - Course when treated and untreated with electric shock, Arch. Neurol. Psychiat., 60 (1948) 37-48. Morrison, J., Clancy, J., Crowe, R. and Winokur, G., The Iowa 500, Part 1 (Diagnostic
225 and schizophrenia), Arch. Gen. Psychiat., 27 (1972) validity in mania, depression, 457-461. Morrison, J., Winokur, G., Crowe, R. and Clancy, J., The Iowa 500 -The first follow-up, Arch. Gen. Psychiat., 29 (1973) 678-682. Robins, E., Murphy, G.E., Wilkerson, R.H., Gassner, S. and Kayes, J., Some clinical considerations in the prevention of suicide based on a study of 134 successful suicides, Amer. J. Publ. Health, 49 (1959) 888-898. Tsuang, M.T. and Woolson, R.F., Mortality in schizophrenia, mania, depression and surgical controls - A comparison with general population mortality, Brit. J. Psychiat., 130 (1977) 162-166. Tsuang, M.T. and Woolson, R.F., Excess mortality in schizophrenia and affective disorders - Do suicides and accidental deaths solely account for this excess? Arch. Gen. Psychiat., 35 (1978) 1181-1185. Winokur, G., Morrison, Clancy J. and Crowe, R., The Iowa 500, Part 2 (A blind family history comparison of mania, depression, and schizophrenia), Arch. Gen. Psychiat., 27 (1972) 462-464. Ziskind, E., Somerfeld-Ziskind, E. and Ziskind, L., Metrazol and electroconvulsive theraapy of the affective psychoses, Arch. Neurol. Psychiat., 53 (1945) 212-217.
COMMUNICATION OF SUICIDAL UNIPOLAR DEPRESSION A Forty
RICHARD
219
INTENT
AND SUICIDE
IN
Year Follow-Up
C. FOWLER
l, MING T. TSUANG
2 and ZIAD KRONFOL
*
t Veterans Administration Hospital and University of California, San Diego, School of Medicine, San Diego, CA 92161 and ’ University of Iowa College of Medicine, Iowa City, IA 52242 (U.S.A.)
SUMMARY Two hundred and 25 unipolar depressives hospitalized during the 1930’s were classified on the basis of documented communication of suicidal intent. A long term follow-up revealed 15 of the former patients had died by suicide. Communicated suicidal intent was documented in the index hospitel record of all 15. The presence of communicated intent may distinguish a group of unipolar depressives at risk for suicide from those not at risk.
INTRODUCTION
Depression remains the most frequently diagnosed psychiatric condition in cases of suicide (Barraclough et al. 1974). While psychiatric treatment has been successful in lowering the risk of suicide in depressive illness (Huston and Lecher 1948; Ziskind et al. 1945; Avery and Winokur 1976), there are depressives who suicide in spite of treatment (Barraclough et al. 1974) or never receive treatment. Suicide in the former group deserves particular scrutiny from the health professions because of the possibility of more successful therapeutic intervention. A necessary step for successful intervention is the accurate assessment of suicide risk. Psychiatrists have used various guidelines for identifying the suicidal depressive. Robins et al. (1959) have shown that it is the older male depressive who is a particular risk in America. In a British study Barraclough et aI.
Reprint CA 92131,
requests U.S.A.
to Dr. Fowler,
Veterans
Administration
Hospital
(116),
San Diego,
220
(1974) confirmed that the older depressive was a high risk but did not find a sex differential. The Barraclough et al. (1974) study also found a disproportionately high number of single and widowed individuals in depressives who had completed suicide. Unfortunately, the above variables are of limited help in assessing the suicide potential of the individual depressive because suicide occurs in all age and marital groups, as well as in both sexes. Factors that are closely associated with the act of suicide may be more helpful in assessing suicide potential in the individual depressive. The communication of suicidal intent, either by a direct statement or by indirect reference to death or suicide, is such a factor. The frequencies of such communication in the Robins et al. (1959) and Barraclough et al. (1974) studies are 68% and 58%, respectively. A prospective inquiry of those suicidal depressives seeking treatment, may yield an even higher rate of communicated intent. Thus, the communication or non-communication of intent may provide the psychiatrist with the means to determine whether an individual depressive is at risk for suicide. The present report tests this hypothesis on a population of hospitalized unipolar depressives. Two hundred and 25 unipolar depressives were divided into two groups according to the presence or absence or suicidal ideas and/or attempts. Forty year follow-up data provided the frequency of suicide in each group. METHODS
Previous reports have described the clinical, follow-up, and family data of 525 functional psychotics discharged from Iowa Psychopathic Hospital 40 years ago (Morrison et al. 1972, 1973; Winokur et al. 1972). These patients were selected according to the Washington University research criteria for psychiatric illness (Feighner et al. 1972) and included 225 unipolar depressives, the subjects of this report. The notation of suicidal ideas and/or attempts was previously determined. The basis for this determination was information from the record of the index hospitalization (Morrison et al. 1972). All patients who had no evidence of suicidal ideas during the index illness or made no suicide attempts at any time were placed in one group (NSIA) and all remaining depressives were placed in the other (SIA). This latter group included 64 patients with a history of one or more suicide attempts and 99 with suicidal ideas alone. The follow-up procedure, mortality rate (through December 31, 1974), and contribution of suicides and accidents to this mortality rate have been previously reported (Tsuang and Woolson 1977, 1978). A successful long term follow-up was accomplished on 221 (98%) of the depressives. Of these, 159 (74%) were deceased. The cause of death for each of the deceased was determined on the basis of information from death certificates and family members. Unnatural deaths with evidence of suicidal intent were classified as suicides. This was done without knowledge of the NSIA-SIA classification.
221
Statistical comparisons),
analysis of the catagorical unless otherwise noted.
data used the chi-square
test (2 X 2
RESULTS
There were 62 depressives who had not communicated suicidal intent and were therefore placed in the NSIA group. The remaining 163 depressives had communicated intent and thus comprised the SIA group. The demographic profile of these two groups (Table 1) indicates no differences regarding age, sex, education, marital status, and employment status. Similarly, a wide range of depressive and psychiatric symptoms did not differentiate the two groups. These included the following depressive symptoms: dysphoria, anorexia, weight loss, insomnia, loss of energy, agitation, psychomotor retardation, loss of interest, decreased libido, feelings of selfreproach or guilt, difficulty thinking, and diurnal variation. Psychotic symptoms included delusions, hallucinations, thought disorders, and catatonia. Identifiable precipitants and family history variables also failed to differentiate the two groups. The two groups were divergent, however, regarding the short term course. Information had been recorded in the medical record about the course subsequent as well as prior to the index hospitalization. This is summarized in Table 2. The NSIA patients were more likely to have had a psychiatric hospitalization prior to the index hospitalization, though there was only a trend toward more prior depressive episodes in this group. Data about the subsequent course indicates the NSIA group was less likely to have a subsequent depressive episode, though the initial recovery rates from the index episode were similar. There were no differences between the groups regarding chronicity or subsequent psychiatric hospitalization. Because of the intergroup difference regarding prior psychiatric hospitalization, the data analysis of subsequent course was limited to depressives whose index hospitalization occurred during the first depressive episode. The designation ‘first depressive episode’ was not synonymous with ‘first psy-
TABLE
1
DEMOGRAPHIC
PROFILE
OF UNIPOLAR
DEPRESSIVES NSIA N = 62 (%)
Age at onset of illness (X f SD) Age at index hospitalization (X * SD) Female Completed high school Married Employed
37 45 34 28 38 46
+ 14.19 f 12.95 (55) (45) (61) (75)
SIA N = 163 (%) 38 44 90 80 129 134
f 12.50 f 11.49 (55) (49) (76) (82)
P
NS NS NS NS NS NS
222 TABLE
2
COURSE OF UNIPOLAR DEPRESSION HOSPITALIZATION (BASED ON REVIEW
Prior depressive episode hospitalization Subsequent recovery without relapse recovered before subsequent no recovery outcome uncertain hospitalization
episode
PRIOR AND SUBSEQUENT OF HOSPITAL RECORD)
TO
INDEX
NSIA N = 62 (%)
SIA N = 163 (%)
P
31 (50) 16 (26)
66 (40) 21(13)
NS GO.02
25 (40)
50 39 34 40 29
NS GO.02 NS NS NS
6 (lo) 19 (31) 12 (19) 9 (15)
(31) (24) (21) (25) (18)
_
chiatric hospitalization’ as 6 (19%) of the 31 NSIA depressives and 12 (12%) of the 97 SIA depressives hospitalized during their first depressive episode had prior psychiatric hospitalizations (this intergroup difference is not significant). Table 3 summarizes the data about subsequent course for this subgroup of depressives. It indicates that the great majority of patients in both the NSIA and SIA groups initially recovered from the depressive episode; however, the SIA group continued to have a higher rate of subsequent relapse. The mortality data at the 40 year follow-up is summarized in Table 4. Over two-thirds of both groups were deceased at the time of follow-up. Of these, 15 patients were judged to have died by suicide. All 15 of the suicides were in the SIA group, a significant difference. Eleven of the suicides were in the SIA subgroup admitted during their first episode. When the analysis is limited to the depressives admitted during their first episode, the difference remains significant (Fishers exact test = 0.041, one-tailed).
TABLE
3
SUBSEQUENT SODE (BASED
COURSE FOR DEPRESSIVES HOSPITALIZED ON REVIEW OF HOSPITAL RECORD)
Recovery without relapse Recovered before subsequent No recovery Outcome uncertain Subsequent hospitalization
episode
DURING
FIRST
EPI-
NSIA N = 31 (%)
SIA N = 98 (%)
P
25 (81)
60 (62) 24 (25)
GO.05 GO.05 NS NS NS
2 4 6 7
(06) (13) (69) (23)
9 (09) 4 (94) 28 (29)
223 TABLE
4
MORTALITY
AT 40-YEAR
FOLLOW-UP
FOR
NSIA
SIA
Alive Suicide Non-suicide death No follow-up
13 (21%) O( 0%) 49 (79%) O( 0%)
45 15 99 4
Total
62
a Fisher Exact
Test, P = 0.0132,
UNIPOLAR
DEPRESSIVES
(28%) ( 9%)a (61%) ( 2%)
163 two-tailed
DISCUSSION
A comparison based on the presence or absence of communicated suicidal intent indicates similarities on demographic, symptom, and family illness variables for this population of unipolar depressives. The only observed differences concern the course of depressive illness both prior and subsequent to the index hospitalization. The excess of prior psychiatric hospitalization in the group defined by no communication of suicidal intent is paradoxical because suicidal ideas or attempts are a major reason for hospitalization of the depressive. There are, however, at least two possible explanations for this finding. The NSIA group could have more illness, either episodic or chronic, prior to the index hospitalization. We cannot fully assess this possibility because there was no recorded measure of chronicity for the period prior to the index hospitalization. However, the longer duration since the initial onset of illness (8 years vs 6 years in the SIA group) and the trend toward more episodes in this group provides some support for this explanation. Another possibility is that the difference in prior hospitalization is an artifact of the patients’ understanding of their illness. Although a patient’s perception could increase as well as decrease the likelihood of hospitalization, perceptions that decrease the likelihood are of particular concern because they can preclude necessary treatment. As an example there were patients in the SIA group who were hospitalized only after a serious suicide attempt prompted medical and psychiatric intervention. If these patients did not understand they were ill and in need of psychiatric care, they may have differed from patients in the NSIA group in their willingness to accept prior psychiatric treatment and hospitalization. Unfortunately, we did not have data available to assess such a possibility. The greater frequency of subsequent depressive episodes in the SIA group suggests that the risk of suicide increased with the number of depressive episodes. However, suicide and subsequent depressive episodes were not independently assessed in the original data collection. Consequently, depres-
224
sives who committed suicide during the short-term follow-up (the only interval in which subsequent depressive episodes were recorded) may have been coded as having a subsequent depressive episode even though the only known evidence of an episode was suicide. Therefore, it cannot be excluded from the present data that the risk of suicide increases with further depressive episodes. Nonetheless, the possible association of subsequent episodes and suicide provides hope for suicide prevention. In the Barraclough study (1972) of completed suicides, 69% of the cases with primary affective disorder had more than one episode and 33% met rigorous criteria for lithium prophylaxis. Consequently, minimizing the risk of further depressive episodes through lithium carbonate or other prophylactic therapies may have a major impact on the high suicide rate associated with depressive illness (Guze and Robins 1970). The absence of suicides in the NSIA group, is not comparable with other studies of completed suicide (Robins et al. 1959; Barraclough et al. 1974) because the latter are retrospective regarding the communication of suicidal intent. Therefore their finding that a minority of depressives do not communicate intent prior to suicide may reflect a methodological limitation of such studies. Only further prospective studies can assess the risk of suicide for depressives who do not communicate suicidal intent. There is an important need for such studies. Present treatment approaches may often proceed from the assumption that all unipolar depressives are at risk for suicide. This risk is one justification for the use of treatment modalities, especially antidepressant medication and electroconvulsive therapy, that in themselves carry risks. Although the risk of suicide is not the only indication for such therapies, psychiatrists use of such treatment modalities may be modified if it is established that some unipolar depressives are not at risk for suicide. The present study suggests that depressives who do not communicate suicidal intent are not at risk. Further investigation of this finding is warranted, however, before concluding that lack of communicated intent defines a group of depressives not at risk for suicide. REFERENCES Avery, D. and Winokur, G., Mortality in depressed patients treated with electroconvulsive therapy and antidepressants, Arch. Gen. Psychiat., 33 (1976) 1029-1037. Barraclough, B., Suicide prevention, recurrent affective disorder and lithium, Brit. J. Psychiat., 121 (1972) 391-392. Barraclough, B., Bunch, J., Nelson, B. and Sainsbury, P., A hundred cases of suicide Clinical aspects, Brit. J. Psychiat., 125 (1974) 355-373. Feighner, J.P., Robins, E., Guze, S.B., Woodruff, R.A., Winokur, H. and Munoz, R., Diagnostic criteria for use in psychiatric research, Arch. Gen. Psychiat., 26 (1972) 57-63. Guze, S.B. and Robins, E., Suicide and primary affective disorders, Brit. J. Psychiat., 117 (1970) 437-438. Huston, P.E. and Lecher, L.M., Manic-depressive psychosis - Course when treated and untreated with electric shock, Arch. Neurol. Psychiat., 60 (1948) 37-48. Morrison, J., Clancy, J., Crowe, R. and Winokur, G., The Iowa 500, Part 1 (Diagnostic
225 and schizophrenia), Arch. Gen. Psychiat., 27 (1972) validity in mania, depression, 457-461. Morrison, J., Winokur, G., Crowe, R. and Clancy, J., The Iowa 500 -The first follow-up, Arch. Gen. Psychiat., 29 (1973) 678-682. Robins, E., Murphy, G.E., Wilkerson, R.H., Gassner, S. and Kayes, J., Some clinical considerations in the prevention of suicide based on a study of 134 successful suicides, Amer. J. Publ. Health, 49 (1959) 888-898. Tsuang, M.T. and Woolson, R.F., Mortality in schizophrenia, mania, depression and surgical controls - A comparison with general population mortality, Brit. J. Psychiat., 130 (1977) 162-166. Tsuang, M.T. and Woolson, R.F., Excess mortality in schizophrenia and affective disorders - Do suicides and accidental deaths solely account for this excess? Arch. Gen. Psychiat., 35 (1978) 1181-1185. Winokur, G., Morrison, Clancy J. and Crowe, R., The Iowa 500, Part 2 (A blind family history comparison of mania, depression, and schizophrenia), Arch. Gen. Psychiat., 27 (1972) 462-464. Ziskind, E., Somerfeld-Ziskind, E. and Ziskind, L., Metrazol and electroconvulsive theraapy of the affective psychoses, Arch. Neurol. Psychiat., 53 (1945) 212-217.