A comparison of self-reported risk and protective factors and the death implicit association test in the prediction of future suicide attempts in adolescent emergency department patients.

BACKGROUND: Concerns have been raised about the utility of self-report assessments in predicting future suicide attempts. Clinicians in pediatric emergency departments (EDs) often are required to assess suicidal risk. The Death Implicit Association Test (IAT) is an alternative to self-report assessment of suicidal risk that may have utility in ED settings. METHODS: A total of 1679 adolescents recruited from 13 pediatric emergency rooms in the Pediatric Emergency Care Applied Research Network were assessed using a self-report survey of risk and protective factors for a suicide attempt, and the IAT, and then followed up 3 months later to determine if an attempt had occurred. The accuracy of prediction was compared between self-reports and the IAT using the area under the curve (AUC) with respect to receiver operator characteristics. RESULTS: A few self-report variables, namely, current and past suicide ideation, past suicidal behavior, total negative life events, and school or social connectedness, predicted an attempt at 3 months with an AUC of 0.87 [95% confidence interval (CI), 0.84-0.90] in the entire sample, and AUC = 0.91, (95% CI 0.85-0.95) for those who presented without reported suicidal ideation. The IAT did not add significantly to the predictive power of selected self-report variables. The IAT alone was modestly predictive of 3-month attempts in the overall sample ((AUC = 0.59, 95% CI 0.52-0.65) and was a better predictor in patients who were non-suicidal at baseline (AUC = 0.67, 95% CI 0.55-0.79). CONCLUSIONS: In pediatric EDs, a small set of self-reported items predicted suicide attempts within 3 months more accurately than did the IAT.

Prevention of Depression in At-Risk Adolescents: Moderators of Long-term Response.

In a randomized controlled trial, we found that a cognitive behavioral program (CBP) was significantly more effective than usual care (UC) in preventing the onset of depressive episodes, although not everyone benefitted from the CBP intervention. The present paper explored this heterogeneity of response. Participants were 316 adolescents (M age = 14.8, SD = 1.4) at risk for depression due to having had a prior depressive episode or having current subsyndromal depressive symptoms and having a parent with a history of depression. Using a recursive partitioning approach to baseline characteristics, we (Weersing et al. 2016) previously had identified distinct risk clusters within conditions that predicted depressive episodes through the end of the continuation phase (month 9). The present study used the same risk clusters that had been derived in the CBP group through month 9 to reclassify the UC group and then to examine group differences in depression through month 33. We found that in this overall very high-risk sample, the CBP program was superior to UC among youth in the low-risk cluster (n = 33), characterized by higher functioning, lower anxiety, and parents not depressed at baseline, but not in the middle (n = 95) and high-risk (n = 25) clusters. Across conditions, significantly more depression-free days were found for youth in the low-risk cluster (M = 951.9, SD = 138.8) as compared to youth in the high-risk cluster (M = 800.5, SD = 226.7). Identification of moderators, based on purely prognostic indices, allows for more efficient use of resources and suggests possible prevention targets so as to increase the power of the intervention.

Psychological autopsy study comparing suicide decedents, suicide ideators, and propensity score matched controls: results from the study to assess risk and resilience in service members (Army STARRS).

BACKGROUND: The suicide rate has increased significantly among US Army soldiers over the past decade. Here we report the first results from a large psychological autopsy study using two control groups designed to reveal risk factors for suicide death among soldiers beyond known sociodemographic factors and the presence of suicide ideation. METHODS: Informants were next-of-kin and Army supervisors for: 135 suicide cases, 137 control soldiers propensity-score-matched on known sociodemographic risk factors for suicide and Army history variables, and 118 control soldiers who reported suicide ideation in the past year. RESULTS: Results revealed that most (79.3%) soldiers who died by suicide have a prior mental disorder; mental disorders in the prior 30-days were especially strong risk factors for suicide death. Approximately half of suicide decedents tell someone that they are considering suicide. Virtually all of the risk factors identified in this study differed between suicide cases and propensity-score-matched controls, but did not significantly differ between suicide cases and suicide ideators. The most striking difference between suicides and ideators was the presence in the former of an internalizing disorder (especially depression) and multi-morbidity (i.e. 3+ disorders) in the past 30 days. CONCLUSIONS: Most soldiers who die by suicide have identifiable mental disorders shortly before their death and tell others about their suicidal thinking, suggesting that there are opportunities for prevention and intervention. However, few risk factors distinguish between suicide ideators and decedents, pointing to an important direction for future research.

Neuropsychological deficits in past suicide attempters with varying levels of depression severity.

BACKGROUND: Our previous work identified deficits in interference processing and learning/memory in past suicide attempters who were currently depressed and medication-free. In this study, we extend this work to an independent sample studied at various stages of illness and treatment (mild symptoms, on average) to determine if these deficits in past suicide attempters are evident during a less severe clinical state. METHOD: A total of 80 individuals with a past history of major depression and suicide attempt were compared with 81 individuals with a history of major depression and no lifetime suicide attempts on a battery of neurocognitive measures assessing attention, memory, abstract/contingent learning, working memory, language fluency and impulse control. RESULTS: Past attempters performed more poorly in attention, memory and working memory domains, but also in an estimate of pre-morbid intelligence. After correction for this estimate, tests that had previously distinguished past attempters - a computerized Stroop task and the Buschke Selective Reminding Test - remained significantly worse in attempters. In a secondary analysis, similar differences were found among those with the lowest levels of depression (Hamilton Depression Rating Scale score <10), suggesting that these deficits may be trait markers independent of current symptomatology. CONCLUSIONS: Deficits in interference processing and learning/memory constitute an enduring defect in information processing that may contribute to poor adaptation, other higher-order cognitive impairments and risk for suicidal behavior.

Differential patterns of activity and functional connectivity in emotion processing neural circuitry to angry and happy faces in adolescents with and without suicide attempt.

BACKGROUND: Neural substrates of emotion dysregulation in adolescent suicide attempters remain unexamined. METHOD: We used functional magnetic resonance imaging to measure neural activity to neutral, mild or intense (i.e., 0%, 50% or 100% intensity) emotion face morphs in two separate emotion-processing runs (angry and happy) in three adolescent groups: (1) history of suicide attempt and depression (ATT, n=14) ; (2) history of depression alone (NAT, n=15) ; and (3) healthy controls (HC, n=15). Post-hoc analyses were conducted on interactions from 3 group x 3 condition (intensities) whole-brain analyses (p<0.05, corrected) for each emotion run. RESULTS: To 50% intensity angry faces, ATT showed significantly greater activity than NAT in anterior cingulate gyral­dorsolateral prefrontal cortical attentional control circuitry, primary sensory and temporal cortices; and significantly greater activity than HC in the primary sensory cortex, while NAT had significantly lower activity than HC in the anterior cingulate gyrus and ventromedial prefrontal cortex. To neutral faces during the angry emotion processing run, ATT had significantly lower activity than NAT in the fusiform gyrus. ATT also showed significantly lower activity than HC to 100% intensity happy faces in the primary sensory cortex, and to neutral faces in the happy run in the anterior cingulate and left medial frontal gyri (all p<0.006,corrected). Psychophysiological interaction analyses revealed significantly reduced anterior cingulate gyral­insula functional connectivity to 50% intensity angry faces in ATT v. NAT or HC. CONCLUSIONS: Elevated activity in attention control circuitry, and reduced anterior cingulate gyral­insula functional connectivity, to 50% intensity angry faces in ATT than other groups suggest that ATT may show inefficient recruitment of attentional control neural circuitry when regulating attention to mild intensity angry faces, which may represent a potential biological marker for suicide risk.

Factors Associated With Reasons for Living Among Suicidal Adolescents.

OBJECTIVE: The objective of this study was to identify baseline demographic and clinical factors associated with higher scores on the Reasons for Living Inventory for Adolescents (RFL-A) at baseline and over follow-up. METHOD: Using data from a pilot clinical trial of a brief intervention for suicidal youth transitioning from inpatient to outpatient, we identified univariate associations of baseline characteristics with RFL-A and used regression to identify the most parsimonious subset of these variables. Finally, we examined to what extent changes in these characteristics over time were related to changes in RFL-A. RESULTS: Univariate analyses found that better external functional emotion regulation and social support were associated with higher RFL-A scores; more self-reported depression, internal dysfunctional emotion regulation, sleep disturbance, anxiety, and distress tolerance were associated with lower RFL-A scores. Multiple linear regression identified internal dysfunctional emotion regulation and external functional emotion regulation as the most parsimonious set of characteristics associated with RFL-A. Improvement in internal emotion regulation, sleep, and depression were related to improvements in RFL-A over time. CONCLUSION: Our findings indicate that emotion regulation-specifically maladaptive internal strategies and use of external resources-is strongly associated with RFL-A. Improvements in internal emotion regulation (r = 0.57), sleep (r = -0.45), and depression (r = -0.34) were related to increases in RFL-A.HIGHLIGHTSIn the literature, greater reasons for living are associated with lower risk for future suicidal ideation and suicide attempts.The most salient correlate of concurrent and future lower RFL-A was dysfunctional internal emotion regulation. Improved sleep and decreases in depression were correlated with increases in RFL-A.

Chemical identification of a tumor-derived angiogenic factor.

Neoplasms produce substances that induce blood vessel formation (angiogenesis). Fractions from ethanol extracts of the Walker 256 carcinoma were isolated by silica column chromatography and C18 reversed-phase high-performance liquid chromatography. Two of the isolated fractions induced neovascularization when tested in the rabbit corneal micropocket assay. One of the fractions was identified as nicotinamide by desorption-electron impact mass spectrometry, nuclear magnetic resonance spectroscopy, and gas chromatography-mass spectrometry. The second active fraction contained nicotinamide as part of a more complex, as yet unidentified, molecular arrangement. Microgram quantities of commercial nicotinamide induced neovascularization in the corneal micropocket assay and in the chick chorioallantoic membrane assay.

Morphine in cow and human milk: could dietary morphine constitute a ligand for specific morphine (mu) receptors?

Morphine has been found in cow and human milk at concentrations of 200 to 500 nanograms per liter. Multistep purification yields a material that has immunological, biological, pharmacological, and chemical properties identical to those of morphine. Similar morphine-like material, which has been tentatively identified in some common plant sources, may be a ubiquitous dietary constituent and a possible source for the material in milk. Since morphine (mu) receptors have a low affinity for enkephalins, and since morphine-like materials have been described in brain and intestine, it is possible that morphine in food may be the source of this material and a normal ligand specific for mu receptors.

Suicidal behavior runs in families. A controlled family study of adolescent suicide victims.

BACKGROUND: While previous studies have shown an increased rate of suicidal behavior in the relatives of suicide victims, it is unclear if this is attributable merely to increased familial rates of psychiatric disorders. Therefore, we conducted a family study of adolescent suicide victims (suicide probands) and community control probands (controls) to determine if the rates of suicidal behavior were higher in the relatives of adolescent suicide probands even after adjusting for differences in the familial rates of psychiatric disorders. METHOD: The relatives of 58 adolescent suicide probands and 55 demographically similar controls underwent assessment for Axis I and II psychiatric disorders, lifetime history of aggression, and history of suicidal behavior (attempts and completions) using a combination of family study and family history approaches. RESULTS: The rate of suicide attempts was increased in the first-degree relatives of suicide probands compared with the relatives of controls, even after adjusting for differences in rates of proband and familial Axis I and II disorders (odds ratio, 4.3; 95% confidence intervals, 1.1-16.6). On the other hand, the excess rate of suicidal ideation found in the relatives of suicide probands was explained by increased familial rates of psychiatric disorders. Among suicide probands, higher ratings of aggression were associated with higher familial loading for suicide attempts. CONCLUSIONS: Liability to suicidal behavior might be familially transmitted as a trait independent of Axis I and II disorders. The transmitted spectrum of suicidal behavior includes attempts and completions, but not ideation, and the transmission of suicidal behavior and aggression are related.

Clinical outcome after short-term psychotherapy for adolescents with major depressive disorder.

BACKGROUND: Cognitive behavioral therapy has been shown to be more efficacious than alternative psychosocial interventions for the acute treatment of adolescents with major depressive disorder. However, the long-term impact of brief psychosocial interventions on the course of adolescent depression is not well established. METHODS: One hundred seven adolescents with major depressive disorder randomly assigned to 12 to 16 weeks of cognitive behavioral therapy, systemic behavioral family therapy, or nondirective supportive therapy were evaluated for 2 years after the psychotherapy trial to document the subsequent course and predictors of major depressive disorder. RESULTS: There were no long-term differential effects of the 3 psychotherapies. Most participants (80%) recovered (median time, 8.2 months from baseline), and 30% had a recurrence (median time, 4.2 months from recovery). Twenty-one percent were depressed during at least 80% of the follow-up period. Severity of depression (at baseline) and presence of self-reported parent-child conflict (at baseline and during the follow-up period) predicted lack of recovery, chronicity, and recurrence. Despite the similarity to clinically referred patients at baseline, patients recruited via advertisement were less likely to experience a recurrence. CONCLUSIONS: There were no significant differences in long-term outcome among cognitive behavioral therapy, systematic behavioral family therapy, and nondirective supportive therapy. While most participants in this study eventually recovered, those with severe depression and self-perceived parent-child conflict are at greater risk for chronic depression and recurrences.

A clinical psychotherapy trial for adolescent depression comparing cognitive, family, and supportive therapy.

BACKGROUND: Previous studies in nonclinical samples have shown psychosocial treatments to be efficacious in the treatment of adolescent depression, but few psychotherapy treatment studies have been conducted in clinically referred, depressed adolescents. METHODS: One hundred seven adolescent patients with DSM-III-R major depressive disorder (MDD) were randomly assigned to 1 of 3 treatments: individual cognitive behavior therapy, systemic behavior family therapy (SBFT), or individual nondirective supportive therapy (NST). Treatments were 12 to 16 sessions provided in as many weeks. Intent-to-treat analyses were conducted using all follow-up data. RESULTS: Of the 107 patients enrolled in the study, 78 (72.9%) completed the study, 4 (3.7%) never initiated treatment, 10 (9.3%) had exclusionary criteria that were undetected at entry, 8 (7.5%) dropped out, and 7 (6.5%) were removed for clinical reasons. Cognitive behavior therapy showed a lower rate of MDD at the end of treatment compared with NST (17.1% vs 42.4%; P = .02), and resulted in a higher rate of remission (64.7%, defined as absence of MDD and at least 3 consecutive Beck Depression Inventory scores < 9) than SBFT (37.9%; P = .03) or NST (39.4%; p = .04). Cognitive behavior therapy resulted in more rapid relief in interviewer-rated (vs both treatments, P = .03) and self-reported depression (vs SBFT, P = .02). All 3 treatments showed significant and similar reductions in suicidality and functional impairment. Parents' views of the credibility of cognitive behavior therapy improved compared with parents' views of both SBFT (P = .01) and NST (P = .05). CONCLUSIONS: Cognitive behavior therapy is more efficacious than SBFT or NST for adolescent MDD in clinical settings, resulting in more rapid and complete treatment response.

Risk factors for adolescent suicide. A comparison of adolescent suicide victims with suicidal inpatients.

The characteristics of adolescent suicide victims (n = 27) were compared with those of a group at high risk for suicide, suicidal psychiatric inpatients (n = 56) who had either seriously considered (n = 18) or actually attempted (n = 38) suicide. The suicide victims and suicidal inpatients showed similarly high rates of affective disorder and family histories of affective disorder, antisocial disorder, and suicide, suggesting that among adolescents there is a continuum of suicidality from ideation to completion. However, four putative risk factors were more prevalent among the suicide victims: (1) diagnosis of bipolar disorder; (2) affective disorder with comorbidity; (3) lack of previous mental health treatment; and (4) availability of firearms in the homes, which taken together accurately classified 81.9% of cases. In addition, suicide completers showed higher suicidal intent than did suicide attempters. These findings suggest a profile of psychiatric patients at high risk for suicide, and the proper identification and treatment of such patients may prevent suicide in high-risk clinical populations.

Neuroendocrine response to 5-hydroxy-L-tryptophan in prepubertal children at high risk of major depressive disorder.

BACKGROUND: Altered serotonergic function has been observed in prepubertal children and adults with an acute episode of major depressive disorder (MDD). However, it is not known whether these alterations are present prior to the onset of MDD. METHODS: A serotonergic precursor, 5-hydroxy-L-tryptophan (L-5HTP) (oxitriptan) (0.8 mg/kg), was administered through an indwelling catheter to 36 children at high risk of MDD (with high family loading for MDD), 31 children with MDD, and 23 low-risk normal controls (with low family loading for mood disorders and no history of psychopathology). Blood samples for cortisol, prolactin (PRL), and growth hormone were obtained every 15 minutes for 180 minutes, beginning 30 minutes before L-5HTP infusion. RESULTS: Children at high risk of MDD and children with MDD had similar hormonal responses following L-5HTP infusion. After controlling for baseline values, both groups secreted significantly less cortisol and more PRL than did the low-risk normal controls, with the PRL finding being limited to girls. There were no between-group differences in baseline cortisol, PRL, or growth hormone secretion measures. CONCLUSIONS: Before the onset of affective illness, high-risk children had the same pattern of neuroendocrine response to the L-5HTP challenge as did children with MDD. These results extend earlier findings of altered serotonergic regulation in association with early-onset depression and indicate that these alterations may represent a trait marker for depression in children.

Growth hormone secretion in children and adolescents at high risk for major depressive disorder.

BACKGROUND: Decreased growth hormone (GH) response to pharmacologic stimulation has been found in children and adolescents during an episode of major depressive disorder and after recovery. In this study, we sought to determine whether GH secretion is similarly altered in children and adolescents who had never experienced depression but were at high risk of developing depression. METHODS: Subjects were 8 through 16 years of age and selected for high- and low-risk status according to familial loading for mood disorders. Sixty-four high-risk and 55 low-risk healthy subjects participated in the study, which assessed the following GH measures: (1) GH before growth hormone-releasing hormone (GHRH) infusion, every 15 minutes for 30 minutes; (2) GH response after intravenous infusion of GHRH (0.1 microg/kg), every 15 minutes for 90 minutes; and (3) nocturnal GH every 20 minutes from 9 PM until morning awakening. RESULTS: After stimulation with GHRH, the high-risk subjects secreted significantly less GH compared with the low-risk healthy controls (effect sizes for mean and peak GH, 0.52 [P =.007] and 0.40 [P =.04], respectively). In contrast, there were no between-group differences in the pre-GHRH and nocturnal GH secretion levels. Exposure to recent stressors was not associated with GH secretion. CONCLUSIONS: Taken together with previous evidence of decreased GH after GHRH infusion in acutely depressed and recovered children, these results indicate that the decreased GH response found in high-risk subjects may represent a trait marker for depression in children and adolescents.

Bipolar I and II versus unipolar depression: clinical differences and impulsivity/aggression traits.

OBJECTIVE: To investigate distinguishing features between bipolar I, II and unipolar depression, and impulsivity/aggression traits in particular. METHODS: Six hundred and eighty-five (n=685) patients in a major depressive episode with lifetime Unipolar (UP) depression (n=455), Bipolar I (BP-I) disorder (n=151), and Bipolar II (BP-II) (n=79) disorder were compared in terms of their socio-demographic and clinical characteristics. RESULTS: Compared to unipolar patients, BP-I and BP-II depressed patients were significantly younger at onset of their first depressive episode, and were more likely to experience their first depressive episode before/at age of 15. They also had more previous affective episodes, more first- and second-degree relatives with history of mania, more current psychotic and subsyndromal manic symptoms, and received psychopharmacological and psychotherapy treatment at an earlier age. Furthermore, BP-I and BP-II depressed patients had higher lifetime impulsivity, aggression, and hostility scores. With regard to bipolar subtypes, BP-I patients had more trait-impulsivity and lifetime aggression than BP-II patients whereas the latter had more hostility than BP-I patients. As for co-morbid disorders, Cluster A and B Personality Disorders, alcohol and substance abuse/dependence and anxiety disorders were more prevalent in BP-I and BP-II than in unipolar patients. Whereas the three groups did not differ on other socio-demographic variables, BP-I patients were significantly more often unemployed that UP patients. CONCLUSION: Our findings comport with major previous findings on differences between bipolar and unipolar depression. As for trait characteristics, bipolar I and II depressed patients had more life-time impulsivity and aggression/hostility than unipolar patients. In addition, bipolar I and II patients also differed on these trait characteristics.

Low growth hormone response to growth hormone-releasing hormone in child depression.

BACKGROUND: This study examined growth hormone (GH) response to growth hormone-releasing hormone (GHRH) in a large sample of depressed children compared with normal control children. Within-subject comparisons were also performed in control subjects to examine test-retest reliability and in depressed children comparing episode versus clinical recovery. METHODS: The sample included depressed children (n = 82) and normal control children (n = 55) group-matched for age, gender, and pubertal status; the mean ages were 11.2 +/- 1.7 and 11.2 +/- 1.8 years, respectively. We gave GHRH (0.1 mcg/Kg) at 9 AM, and serum GH levels were determined every 15 min from -30 min through +90 min of the GHRH infusion. A subgroup of normal control subjects (n = 11) repeated the protocol for test-retest reliability within a 2-month interval. A subgroup of depressed children (n = 20) were restudied off all medications following full clinical remission from depression. RESULTS: The mean GH response to GHRH was significantly lower in the depressed group (8.7 ng/mL +/- SEM 0.9) compared with normal control children [12.2 ng/mL +/- SEM 1.3; t(135) = 2.59, p =.01 effect size 0.44]. The test-retest reliability of GH response to GHRH was stable (intraclass correlation =.93 for mean post-GH). The GH response to GHRH remained low in subjects restudied during clinical remission from depression. CONCLUSIONS: Depressed children show low GH response to GHRH. The measure appears to be reliable, and the low GH response continues following clinical remission. Further studies are needed to explore the mechanism and relative specificity of this finding.

Comorbidity of substance abuse and other psychiatric disorders in adolescents.

Psychopathology coexisting with substance abuse in adolescents is often encountered in a variety of clinical settings. Research findings suggest a major role for substance use in the etiology and prognosis of psychiatric disorders such as affective disorders, conduct disorder and antisocial personality disorder, attention-deficit hyperactivity disorder, and anxiety disorders. Psychiatric disorders also appear to have an important role in the etiology of and vulnerability to substance use problems in adolescents. Although the comorbidity of substance abuse and other psychiatric disorders in adolescents is recognized as an important factor in the treatment of adolescents, further research is needed to establish its prevalence, genetics, and clinical implications.

Influence of traumatic grief on suicidal ideation among young adults.

OBJECTIVE: The purpose of this study was to examine the influence of traumatic grief on suicidal ideation. METHOD: The Beck-Kovacs Scale for Suicidal Ideation was administered to 76 young adult friends of suicide victims. RESULTS: Traumatic grief was associated with a 5.08 times greater likelihood of suicidal ideation, after control for depression. Comorbid traumatic grief and depression were not associated with a greater likelihood of suicidal ideation. CONCLUSIONS: Syndromal traumatic grief heightens vulnerability to suicidal ideation.

The neurobiology and genetics of suicide and attempted suicide: a focus on the serotonergic system.

Numerous abnormalities have been found in the serotonergic system in suicide attempters and completers. There is considerable evidence that the serotonergic system is partly under genetic control and that as yet unknown genetic factors mediate the risk for suicidal behavior independently of the genetic factors responsible for the heritability of major psychiatric conditions associated with suicide. An argument is made that there is a relationship of genetic variants to intermediate phenotypes, such as impulsivity, psychomotor change, pathological aggression and biological abnormalities including specific gene products. A variety of biological indices have been generated by new approaches using postmortem tissue and in vivo imaging that will provide a rich substrate for further genetic studies.

A simplified high-pressure liquid chromatography method for determining lipophilicity for structure-activity relationships.

A highly deactivated octadecyl-bonded silica column and a mobile phase consisting of an water-methanol mixture in the range of blood pH and ionic strength are used to correlate log kappa' with biological activity for a series of sulfonamides and barbiturates. The results were compared to literature methods by using retention volume (VR) and retention indexes (I). For the nine sulfonamides tested, log VR and log kappa' were used with and without correction for ionization. For each biological end point (protein binding and minimum inhibitor concentration against Eschericia coli from two sources) and each independent variable (log kappa' and log VR) the residual standard derivation for the regression was determined. the standard derivations were compared in an F test for each of 12 relevant regressions. Log kappa' was statistically superior in for cases, while log VR was superior in one case. Overall, the methods were statistically indistinguishable. Log kappa' values and I values for 15 barbiturates were regressed against three biological end points [hypnotic activity (the minimum effective dose in rabbits), inhibition of Arbacia egg cell division, and inhibition of rat brain respiration]. Standard deviations were compared by an F test, and the two methods were indistinguishable as far as the goodness of biological correlations are concerned. Procedures for controlling the column's activity are presented. Choices for an appropriate mobile phase are discussed, and a method of calculating pH and ionic strength in a methanol-aqueous mobile phase is presented.