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 Table of Contents  
Year : 2016  |  Volume : 32  |  Issue : 4  |  Page : 325-331

Self-medication hypothesis in substance-abusing psychotic patients: Can it help some subjects?

1 Department of Psychiatry, Postgraduate Institute of Medical Education and Research, Chandigarh, India
2 Department of Drug De-Addiction and Treatment Centre, Postgraduate Institute of Medical Education and Research, Chandigarh, India

Date of Web Publication9-Nov-2016

Correspondence Address:
Dr. Susanta Kumar Padhy
Department of Psychiatry, Postgraduate Institute of Medical Education and Research, Chandigarh - 160 012
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-9962.193652

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Background and Objectives: The evidence for gself.medication hypothesish (SMH) in patients with dual diagnosis psychosis has been conflicting, though largely not supported, recently. But, still can SMH be a beneficial one in some patients with dual diagnosis remains a question. Methods: The study was conducted at Drug De.addiction and Treatment Centre, Department of Psychiatry, Post Graduate Institute of Medical Education and Research, Chandigarh, a Tertiary Care Hospital in India. This cross.sectional comparative study had psychotic patients with substance use disorder as cases and those without substance use disorder as controls. Demographic details, clinical information, and Brief Psychiatric Rating Scale (BPRS) scores were ascertained for cases and controls. Cases were additionally administered modified Stated Reasons Scale and modified Perceived Effects Scale. Results: Case and controls were comparable on demographic details and duration of psychotic illness, but cases had significantly lower scores on BPRS. The reasons reported for substance abuse in cases were more often nonhedonistic than hedonistic. Perceived effects of major substances of abuse (alcohol, cannabis, and opioids) were different. Alcohol use was associated with perceived decrease in loneliness and cannabis was associated with perceived increase in suspiciousness and delusions. Considerable match was found between reasons for taking the substances and the effects perceived. Interpretation and Conclusions: Incorporating reasons for taking substance and their perceived effects in the treatment regimen would certainly help a subset of such difficult.to.treat patients. India being a low.resource country with a scarcity of experts and specialized dual diagnosis clinics, these findings may have an important implication in the clinical practice.

Keywords: Comorbidity, dual diagnosis, psychosis, substance use

How to cite this article:
Padhy SK, Sarkar S, Basu D, Kulhara P. Self-medication hypothesis in substance-abusing psychotic patients: Can it help some subjects?. Indian J Soc Psychiatry 2016;32:325-31

How to cite this URL:
Padhy SK, Sarkar S, Basu D, Kulhara P. Self-medication hypothesis in substance-abusing psychotic patients: Can it help some subjects?. Indian J Soc Psychiatry [serial online] 2016 [cited 2022 Oct 3];32:325-31. Available from: https://www.indjsp.org/text.asp?2016/32/4/325/193652

  Introduction Top

Community and clinical studies have shown a high prevalence of substance use disorder in patients with schizophrenia and other related psychoses.[1],[2],[3],[4],[5] Lifetime rates of around 60% of the substance use disorder have been reported which are considerably higher than rates of the general population. Moreover, patients with psychosis and substance use disorder have a poorer prognosis in terms of increased rates of relapses and re-hospitalization, greater medical comorbidity, and increased chances of suicide and violence.[6],[7],[8]

The increased occurrence of substance use disorder in patients with psychotic illness raises the question, why various mechanisms have been put forth to explain the association?[9] The self-medication hypothesis (SMH) of Khantzian[10] presents a model to understand the relationship of higher rates of substance use disorders in psychiatric patients. The hypothesis proposes that substance use is a consequence of individuals’ attempts to alleviate or “self-medicate” underlying distressing emotional states or abnormal experiences. The patients find short-term effects of their drug of choice, useful in coping with overwhelming and distressing circumstances.

Studies looking at the reported causes of substance abuse in patients with psychosis and substance use disorders include relief of psychotic symptoms, improvement of mood, and inducement of relaxation with the substance.[11],[12] Many studies have found the relevance and applicability of SMH in patients with substance use disorder and psychosis.[13],[14],[15] However, not all studies support the view that substances are consumed by this set of patients purely for self-medication of psychotic symptoms and emotional distress.[16],[17],[18] It is inconclusive whether and to what extent SMH is applicable in patients with psychosis and substance use disorders and requires further attention.

SMH provides an alternate viewpoint to explain high rates of comorbid substance abuse in patients with psychosis and has implications in the management of the patient. However, empirical studies looking explicitly at SMH in dual diagnosis psychotic patients in a hypothesis-driven manner are few.[14] Hence, this study was specifically planned to understand the applicability of SMH in dual diagnosis psychotic patients.

This study attempted to answer many questions pertinent to SMH. It aimed to find out: (a) whether dual diagnosis patients with psychosis are less symptomatic than psychosis patients without substance use; (b) whether reasons of substance use in dual diagnosis psychotic patients are those apart from exclusively hedonistic (i.e. obtaining pleasure or getting and enjoying “high”); (c) whether different reasons are ascribed for use of different kinds of substances; (d) whether perceived effects of different substances on various symptoms are different; and (e) whether there is some degree of a “match” between reasons for taking substances and their perceived effects. Answers in the affirmative to these five clinical questions were hypothesized to be conceptually compatible with the SMH of substance abuse in dual diagnosis patients with psychotic disorders.[14]

  Methods Top

Study setting

The study was conducted at the general outpatient and inpatient services of the Department of Psychiatry and the Drug De-addiction and Treatment Centre (DDTC) of a Tertiary Care Center in North India. The center is a general medical hospital encompassing psychiatric and substance use treatment services with facility for outdoor and indoor care of patients with psychiatric and substance use disorders. The indoor patients are usually admitted for short stay, and liaison with medical and surgical disciplines is carried out whenever necessary. A range of psychiatric disorders are encountered, and comprehensive management is instituted in the form of pharmacotherapy, psychotherapy, and rehabilitation services. The dual diagnosis patients are catered at both the DDTC as well as the general psychiatry services.

Conduct of the study

The present study was a case–control study with a cross-sectional design. The cases comprised 50 dual diagnosis patients with substance use disorder and psychosis. The psychotic illnesses included schizophrenia, schizoaffective disorder, psychosis unspecified, persistent delusional disorder, or other nonorganic psychosis as per diagnostic criteria of International Classification of Diseases 10 (ICD 10).[19] Only those cases were included who had a diagnosis of dependence or harmful use of any substance according to ICD 10 criteria in the preceding 1 month.[19] Patients with dependence or harmful use of more than one substance (except tobacco) were not included in the study. Potential substance-induced psychotic disorders were excluded, and only those cases were taken who had psychotic illness prior to harmful use of the substance or psychotic illness was present for at least 2 weeks in the substance-free period. The controls comprised 50 patients with psychotic illness who never met ICD 10 criteria for a diagnosis of harmful use or dependence for any substance. Grossly, uncooperative patients for a meaningful complete intake interview (e.g., mental retardation, severe formal thought disorder preventing meaningful communication, mute, acute intoxication, or withdrawal state) were excluded from both the groups. Substance-induced psychotic disorder, schizotypal disorders, documented neurological, or organic brain syndrome were also excluded from both groups.

The study was conducted after the approval of the Institute Research and Ethics Committee. The participants were recruited after obtaining informed consent from the patients or their parents. Demographic and clinical details were obtained from both the cases and controls who were also administered the Brief Psychiatric Rating Scale (BPRS). The cases were additionally administered questionnaire for ascertaining age at onset of dependence (QAAO), modified Stated Reasons Scale (SRS), and modified Perceived Effects Scale (PES). All the assessments were done in a single setting by one of the authors (SP) which minimized inter-observer variation.


Brief Psychiatric Rating Scale[20]

This is an 18-item scale that has been used extensively for measuring psychopathology in psychotic patients. The scale is interviewer administered and requires approximately 10–15 min to complete. This scale has shown acceptable validity and reliability as has often been used in efficacy studies to measure the change in psychopathology with time.

Questionnaire for ascertaining age at onset of dependence[21]

It is a 21-item questionnaire which is used in determining the age of onset of substance dependence. It has been found to have good inter-rater reliability and validity, and ascertains the age of onset of dependence in a structured manner.

Modified Stated Reasons Scale

The original scale[1] looked at the reported reasons of substance use and contained 15 items with dichotomous (yes/no) responses to various reasons. The scale was modified and expanded to tap as many psychotic symptoms as possible by adding many items, and the scoring was changed to 5 point Likert type. The modified scale has 52 items. The face validity and ease of applicability of this expanded questionnaire were tested in patients with psychosis and substance use disorder, and the scale was found to be representative and useful.[22]

Modified Perceived Effects Scale

This scale has 20 items regarding the subjects’ perceived effects of the substances on their mood, thought, and behavior and is scored as increased, same, or decreased. Items such as irritability, anger, confidence, speech output, work output, socialization, abnormal behavior, loneliness, and fearfulness were added to the original 9-item scale[1] to better understand the SMH. This modified questionnaire was tested in a pilot study and was found to be relevant to the experiences of patients with psychosis and substance use disorder.[22]

Statistical analysis

The data on socio-demographic, clinical, and psychometric variables were compared between cases and controls by applying Student’s unpaired t-test for continuous data and χ2 test for categorical data. For the number of reasons of substance use, the mean number of reasons stated in each domain and the mean weighted scores (weights given from 0 to 3 based on Likert responses) were calculated. ANOVA was used to compare the mean scores across the different groups of major substances. For perceived effects of substance use, the effects were computed as either increased, same, or decreased symptoms/attributes due to substance use. The reasons were then matched with the perceived effects of substance use for each of the perceived effect.

  Results Top

The demographic and clinical characteristics of cases and controls are shown in [Table 1]. The cases and the controls did not differ significantly with respect to age, marital status, education, occupation, religion, family type, duration of psychotic illness, type of onset, treatment, and family history of psychiatric illness and substance use. However, the significant differences were observed with respect to the locality of the patients and the diagnosis, with more cases coming from urban background (χ2 = 7.644, P = 0.006) and having more frequent diagnosis of schizophrenia than other nonaffective psychoses (χ2 = 5.844, P = 0.016).
Table 1: Demographic and clinical variables across cases and controls

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Among the cases with substance use and psychosis, the primary substances of abuse in cases were alcohol (27 patients), cannabis (11), opioids (8), and others (4). The mean age of onset of substance use was 28.2 years (±7.5 years). The last consumption of substance was 6.4 (±12.2) days prior to recruitment in the study. The BPRS score of the cases was significantly lower than that of controls (t = 8.370, P < 0.001).

The stated reasons of substance use are depicted in [Table 2]. The reasons had been grouped under various domains and the table shows the number of reasons endorsed and the weighted scores. The general group comprises the hedonistic reasons. The other domains of the reasons were coalesced into the nonhedonistic groups. The table shows that substances were being taken not only for hedonistic purposes but for others such as improving mood and improving biological functions such as sleep.
Table 2: Reasons of substance use

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The perceived effects of the three major substances are depicted in [Table 3]. The table shows whether a particular symptom or attribute (such as anger and irritability) was increased, decreased, or remained same with a particular substance. The table also depicts the match between the stated reason of substance use and the perceived effect in the parenthesis. From the table, it seems that alcohol was perceived to reduce loneliness significantly as compared to opioids and cannabis (χ2 = 10.204, P = 0.037). Furthermore, it was seen that cannabis significantly increased suspiciousness and delusions as compared to alcohol and opioids (χ2 = 10.108, P 0.039 and χ2 = 11.428, P = 0.022, respectively)
Table 3: Matching of perceived effects with reasons

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It was seen that the match between “stated reason” and “perceived effects” for most of the items was at least 50%. The match was overall poorer in the domains of anxiety across the three substances, where the match was up to 50%. This suggested that patients stated reasons of decreased anxiety for substance use, but a lesser proportion perceived actual decrement in anxiety. Among individual substances, alcohol users had lower match (<50%) with only anxiety. Cannabis had lower match with anxiety, irritability, anger, suspiciousness, and delusions; whereas opioids had a lower match with anxiety, depression, loneliness, and confidence.

  Discussion Top

This study attempted to find the applicability and validity of SMH in a set of patients with dual diagnosis of psychotic illness and substance use disorder in a clinic-based population.

Psychotic dual diagnosis patients were less symptomatic than psychotic patients without substance use as suggested by lower scores on BPRS in the dual diagnosis group. The two groups had quite similar socio-demographic characteristics, duration of illness, and family history; yet BPRS scores were lower for substance use with psychosis, suggesting lesser degree psychopathology, in congruence to what would be expected as the effect of “self-medication.” A recent meta-analysis[23] showed similar findings about negative symptoms in patients with schizophrenia. Other studies have found similar findings of reduction of mood symptoms and positive symptoms by alcohol and opioids,[13],[24] but a reverse effect with cannabis on positive symptoms.[25] This lesser degree of psychopathology among those with substance use or psychosis could be due to the effect of substance, but the possibility of selection bias does remain.

Whether reasons of substance use more than being exclusively hedonistic was addressed by the study. It was found that substance users reported a wide array of reasons apart from purposes of pleasure as a motivating factor for their substance use. These reasons included improving negative mood, alleviating negative symptoms, improving delusions, and hallucinations. That means such patients not only take substances for enjoyment, but also for “medicating” their illnesses. Other researchers have also reported evidence on similar lines as in the present study.[1],[26] However, caution needs to be exercised while generalizing the findings as some workers have reported that patients with schizophrenia had lower likelihood of reporting emotional and mental issues as reasons of starting alcohol use.[27] Whether different reasons of use are ascribed to different substances could not be addressed from the present study. Similar difficulty in establishing psychopharmacological specificity of drugs of abuse was encountered by Aharonovich et al.[28]

The perceived effects of different substances on various symptoms were found to be distinct in this study. It was seen that alcohol was perceived to reduce loneliness significantly as compared to opioids and cannabis. Loneliness has been reviewed to have a complex interplay with alcohol abuse and seems to be a mediating factor for the development of alcohol dependence.[29] Cannabis was seen to significantly increase suspiciousness and delusions as compared to alcohol and opioids. Other studies have also found cannabis to be associated with an increase in positive symptoms of psychosis.[11],[25]

Finally, exploration of the “matching” between reasons of substance use and perceived effects revealed that most of the items matched. However, lower degree of matching was seen regarding anxiety implying that patients expected a relief in anxiety with substances, but did not experience so. The maximum degree of match was found about enjoyment, calmness, and hallucinations. Cannabis was associated with a lower degree of match across some of the perceived effects, suggesting that effects of using the substance were quite different from the reasons why substances were used.

Taken together, the findings of this study reflect a reasonably consistent but modest support for the SMH of substance abuse in psychotic illness including schizophrenia. The strengths of the study include testing SMH in a broad way by expanding the way information was gathered about self-reported reasons and perceived effects of substances on various domains of psychotic illness. We had enrolled patients who were not grossly symptomatic or incarcerated (thus avoiding bias for already failed self-medication) and had a fairly comparable control group to test the SMH. This study improves upon a previous study[14] in terms of having a greater sample size, recruiting patients from a broader range of psychotic disorders (and not exclusively schizophrenia), and eliciting a broader range of reasons and perceived effects. The modifications in the SRS and the PES which have been tested in a pilot study have extended the number of reasons and effects that were studied.

The limitations of the present study included a restricted sample size. This study being clinic-based, generalization to the community setting should be done with caution. The diagnoses of substance use disorders were made by self–reports and laboratory detection of drugs in body fluids was not conducted. The reporting on the instruments may be influenced by recall bias. Though multiple reasons were recorded, the modified SRS had numerically more nonhedonistic reasons, which may thus translate into greater reporting of nonhedonistic reasons.

  Conclusion Top

This study suggests that SMH is useful in explaining some facets of substance abuse in patients with psychotic illness. Understanding the “self-medicating” reasons of substance use in these patients and the perceptible effects of these substances would have implications in management.

Because favorable outcome of such co-morbid patients demands intensive multimodal treatment (and any small amount of improvement by any means of intervention is the need of the hour for family, patient, and clinician), incorporating this information of reasons for taking substance and the effects perceived thereby and modifying the treatment regimen accordingly (adding medications or rationalizing antipsychotic doses to curtail symptoms; generating alternatives to reasons and perceived effects in the given case while addressing substance use through psychotherapy), would certainly help a subset of such difficult-to-treat patients. India being a low-resource country with a scarcity of experts and specialized dual diagnosis clinics, these findings may have important implication in the clinical practice.


The authors are thankful to the patients and their family for their participation

Financial support and sponsorship


Conflicts of interests

The authors declare no conflicts of interest.

  References Top

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  [Table 1], [Table 2], [Table 3]

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