The General Health Questionnaire (GHQ) is a self-report screening instrument which detects the presence of psychological symptoms . It has demonstrated adequate reliability and validity in both the 12- and 28-item forms, on which a client rates each statement on a four-point scale [1922, 1923]. The GHQ is easy to administer and score and can be used by a range of health professionals; however, this instrument must be purchased. Generally, a score of 10 or more on the GHQ is considered indicative of significant psychological distress and the presence of an underlying psychological disorder. However, it has been suggested that approximately 75% of people who use drugs could be expected to obtain scores of 10 or more upon entering treatment; therefore, clients need to be reassessed after entering treatment . If the client continues to score 10 or more, a more in-depth psychological assessment should be conducted. The GHQ has demonstrated good validity among people attending treatment for AOD use .
The Symptom Checklist-90-Revised (SCL-90-R) is a 90-item self-report questionnaire measuring symptoms of somatisation, obsessive compulsive, interpersonal sensitivity, depression, anxiety, hostility, phobic anxiety, paranoid thoughts, and psychoticism . It has been used among people with AOD-related conditions and has been found to perform better than other general measures of psychological functioning . It has also demonstrated good reliability and validity in clinical and non-clinical populations [1927, 1928]. The scale provides scores for severity, intensity and extensiveness of symptoms and has been shown to have superior sensitivity to competing scales .
Shorter forms of the SCL-90-R have been developed, including the Brief Symptom Inventory with 53 items and the Symptom Assessment, each of which show adequate reliability and validity . However, the long and short forms of the SCL-90-R are copyrighted and must be purchased by registered psychologists . There are both a pen and paper and computerised versions of the SCL-90-R. The former takes 12-15 minutes to complete, is designed for adolescents over the age of 13 years and for adults. A Year 8 reading age is required.
The Brief Psychiatric Rating Scale is an 18-item clinician-administered scale measuring a broad range of psychiatric symptoms. It has been shown to be effective in various populations of people who use AOD [1931, 1932]. However, the reliability and validity of the scale is dependent upon clinical expertise and specific training . It was initially devised as an instrument to assess the symptoms of schizophrenia on five sub-scales of thought disorder, withdrawal, anxiety/depression, hostility and activity [1933, 1934].
The Psychiatric Diagnostic Screening Questionnaire consists of 132-items designed to screen for over 13 different DSM-IV-TR  Axis I disorders, including AOD use disorders . Reports have found the questionnaire to have good validity and reliability along with strong sensitivity and high negative predictive value indicating most cases are detected and most non-cases are indeed non-cases [1935–1937]. These psychometric properties are fundamentally important in a screening instrument and suggest the measure might have broad applicability in numerous health care settings including AOD .
The Beck Depression Inventory (BDI or BDI-II) is a 21-item self-report instrument intended to assess the existence and severity of symptoms of depression [1939, 1940]. Each item is ranked on a four-point scale. The BDI-II has been shown to be a reliable and valid measure of depression particularly in substance misusing populations [1941, 1942]. The Beck Hopelessness Scale is a 20-item scale designed to detect negative feelings about the future and has been found to be a good predictor of suicide attempts . It has been shown to have high internal consistency and test-retest reliability. It also shows good discriminant validity when distinguishing between low and high suicide risk among people with mental health disorders . Instruments such as this can be helpful in ongoing treatment where particular thoughts can continue to be monitored through this and other suicidal thoughts instruments. The Beck Scale for Suicidal Ideation is a 21-item scale assessing suicidal ideation . It has been found to be a valid predictor of admission to hospital for suicidal intention and has high internal consistency and test-retest reliability . This scale has been found to have similar psychometric properties to other reliable and valid measures of suicide risk assessment . The Beck Anxiety Inventory  consists of 21 items, each describing a common symptom of anxiety. The respondent is asked to rate how much they have been bothered by each symptom over the past week on a four-point scale. The items are summed to obtain a total score that can range from 0 to 63. The Beck Anxiety Inventory has similarly shown good reliability and validity for the measurement of anxiety symptoms [1947–1950]. The Beck scales are quite simple to administer but scoring and interpretation must be supervised by a registered psychologist and the cost is high.
The General Anxiety Disorder Screener (GAD-7) also measures anxiety, and was developed as an anxiety-specific version of the Patient Health Questionnaire . This self-report measure consists of seven symptoms of anxiety that correspond to those for GAD in the DSM-IV , and clients rate the frequency with which they have experienced these symptoms in the last fortnight on a four-point scale. These items are summed to obtain a total score, and an additional item assesses the extent to which anxiety symptoms have affected overall functioning. The GAD-7 demonstrates good reliability and validity among people with both single mental and AOD use disorders [1952–1955], as well as the general population . A brief two-item version demonstrates similar diagnostic accuracy to the seven-item version . This measure can be downloaded from: www.phqscreeners.com/select-screener.
The Montreal Cognitive Assessment (MoCA) is a 30-item clinician-administered questionnaire which assesses for cognitive impairment and takes around 10 minutes to complete . This screening tool assesses several cognitive domains including memory, orientation, and attention. Before being able to administer and score the MoCA, clinicians must first complete official MoCA training and be certified. The MoCA should be interpreted in the wider context of a person’s presentation and history , particularly among people with co-occurring conditions due to the complex presentation of this population. As the MoCA is a screening rather than a diagnostic instrument, a low score would indicate the need for referral to a neurocognitive specialist for assessment and/or treatment . The MoCA has been shown to be valid and accurate among people with single mental and AOD use disorders [1960–1963]. One study which evaluated screening tools for cognitive impairment additionally concluded that the MoCA demonstrates the most consistent adequate diagnostic accuracy among adults with AOD use disorders . This measure, and the related training and certification, are available from: www.mocatest.org.
The Patient Health Questionnaire (PHQ-9) is a nine-item self-report questionnaire which assesses the presence and frequency of depression symptoms corresponding to those for major depressive disorder in the DSM-IV [29, 1965, 1966]. Clients rate the frequency with which they have experienced these symptoms in the last fortnight on a four-point scale. These items are summed to obtain a total score, and an additional item assesses the extent to which these symptoms have affected overall functioning. The PHQ-9 demonstrates good reliability and validity among people with both single mental and AOD
use disorders [1952, 1967–1969]. Among people with AOD use disorders, the PHQ-9 similarly predicts an increased risk of suicidal behaviour , and an evaluation of different measures for screening depression concluded the PHQ-9 has the highest diagnostic accuracy . As the PHQ was originally developed to screen for five disorders, there have been several versions of the PHQ developed, including a 15-item scale for somatic symptoms, a seven-item scale for generalised anxiety (the GAD-7; described above), and brief two-item versions of both the depression and anxiety scales . Although the evidence described in this section refers to the nine-item version, the two-item version demonstrates similar diagnostic accuracy . The PHQ-9 is available to download from: www.phqscreeners.com/select-screener.