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 [1169, 1170]. 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 drug users 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 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 with substance abuse populations 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 . 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, as does the SCL-90-R. It has been shown to be effective in various substance use populations [1175, 1176]. However, the reliability and validity of the scale is dependent upon clinical expertise and specific training and therefore may be less appropriate in the AOD sector . 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 [1177, 1178].
The Psychiatric Diagnostic Screening Questionnaire consists of 132-items designed to screen for over 13 different DSM-IV-TR  Axis I disorders, including alcohol/drug related 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 [1179, 1180]. 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 [1181, 1182]. 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 [1183, 1874]. 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. 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 intention to commit suicide . 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 . The Beck Anxiety Inventory  consists of 21 items, each describing a common symptom of anxiety. The respondent is asked to rate how much he or she has 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, though discriminant validity has been questioned [1187-1189]. 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 Spielberger State Trait Anxiety Inventory also measures anxiety  and requires a registered psychologist for scoring, interpretation and the purchasing . The reliability and validity are adequate in general populations, but are unknown within the AOD sector [320, 1190]. The scale consists of 40-items, rated on a four-point scale and takes approximately 10 minutes to complete.
The Traumatic Life Events Questionnaire (TLEQ) is a 23-item self-report measure of 22 types of potentially traumatic events including natural disasters, exposure to warfare, robbery involving a weapon, physical abuse and being stalked . For each event, respondents are asked to provide the number of times it occurred (ranging from ‘never’ to ‘more than 5 times’) and whether fear, helplessness or horror was present (‘yes/no’). The TLEQ has been used successfully within substance-abusing populations. Recent studies have suggested that the psychometric properties of this measure are adequate .
The Trauma History Questionnaire (THQ) developed by Green  is a 24-item self-report measure that examines experiences with potentially traumatic events such as crime, general disaster, and sexual and physical assault using a ‘yes/no’ format. For each event endorsed, respondents are asked to provide the frequency of the event as well as their age at the time of the event. The THQ has demonstrated adequate test-retest reliability.
The PTSD Symptom Scale Self-Report is a screening tool for PTSD which has been used successfully in AOD populations [1194, 1195]. The modified version of the scale only takes 10-15 minutes to administer and measures both frequency and severity of symptoms . The scale consists of 17 items corresponding to 17 DSM-IV-TR  criteria which are rated on a four-point scale of symptom presence.
The PTSD Checklist  is a self-report scale where respondents rate the extent to which they experience each of the DSM-5 PTSD key symptoms. It consists of 20 items corresponding to DSM-5 criteria, which are rated on a five-point severity scale. Whilst no studies have currently examined the psychometric properties of the PCL for DSM-5 in AOD use disorder samples, the previous version of the checklist for DSM-IV-TR has been shown to have good reliability and validity within AOD populations [1197,1198]. However, it is important to note that scores on the DSM-5 version of the PCL cannot be directly compared with scores on the DSM-IV-TR version, due to a change in the rating scale (from 1-5 to 0-4) and an increase in the number of items (from 17 to 20). The checklist is freely available online (http://www.ptsd.va.gov/professional/assessment/adult-sr/ptsd-checklist.asp) but access is restricted to trained clinicians.
The McLean Screening Instrument for Borderline Personality Disorder is a 10-item measure which requires dichotomous (yes or no) answers to questions which correspond to DSM-IV criteria for BPD . The measure has been shown to have good test-retest reliability and internal consistency , as well as good convergent and concurrent validity . Reliability and validity are also good when the measure is used to assess BPD in young people . However, whilst the measure appears to be a feasible way of screening for the presence of BPD symptoms, the authors recommend that the instrument should not be used as a standalone instrument for diagnosing BPD. Instead, it should be used in conjunction with other forms of clinical assessment .